Browsing by Author "Beena, R"

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Assesment of multiple abiotic stress tolerance mechanisms in rice (Oryza sativa L.)
(Department of Plant Biotechnology, College of Agriculture,Vellayani, 2019) Alif Ali, B S; Beena, R
The study entitled “Assessment of multiple abiotic stress tolerance mechanisms in rice (Oryza sativa L.)” undertaken at the Department of Plant Physiology, College of Agriculture, Vellayani during 2018-19. The objective was to study the multiple abiotic viz. drought, salinity and high temperature stress tolerance mechanisms in rice and to validate the identified QTLs for stress tolerance in rice. The investigation comprises four experiments, In experiment I initial screening of 20 rice genotypes for single abiotic stress tolerance was studied. Stresses were induced using different concentrations of PEG6000, NaCl and temperature controlled incubator for providing drought, salinity and temperature stresses respectively. Germination study was carried out using paper towel method. In the first experiment drought stress were given at concentrations -1bar, -3bar, 5bar and -7bar water potentials of PEG6000, salinity stress was given at 100mM, 150mM, 200mM, 250mM NaCl and temperature stress were given at 350C, 400C, 450C and 500C for all 20 rice varieties with two replications. The physio-morphological and biochemical parameters were studied on 14th day of germination. The highest level drought, salinity and temperature stresses at which germination occurred was selected as Dh (-5 bar), Sh (250mM NaCl) and temperature (Th) (350C) respectively. Among 20 rice varieties, PTB-7, PTB-60 and PTB-35 showed maximum seedling vigour at highest level of drought stress (Dh) stress condition Vyttila-9, MO-18 and Vyttila-3 recorded maximum seedling vigour index at highest tolerated level of salinity (Sh) stress condition and N-22, NL-44 and Vyttila -6 showed maximum seedling vigour index at highest tolerated level of temperature stress (Th) stress condition. These nine genotypes were selected for the evaluation of combination stress treatment In the second experiment, The combination stress treatments given were Dh x Sh, Dh x Th, Th x Sh and Dh x Sh x Th. Rice varieties did not germinated at Dh x Sh and Dh x Th. The maximum seedling vigour index at Dh x Sh and combination stress treatment was observed in PTB-7, Vyttila-9, PTB-35 and at Th x Sh was observed in NL-44, MO-18 and N-22 respectively. These rice varieties were selected as tolerant varieties. In experiment III six rice varieties selected from combination stress treatment were evaluated for yield parameters in pot culture experiment. The design of the experiment was CRD with two replications and one control. Drought and salt stress were imposed during reproductive stage for 5 days by applying -5bar PEG6000 and 250mM NaCl solutions respectively into the pots containing rice varieties, Temperature stress was induced using a temperature controlled polyhouse from panicle initiation to maturity stage. Physio-morphological, biochemical and yield parameters were studied under the combination stress treatments. Highest yield under the combination stress treatment of Dh x Sh was observed in PTB-7 and highest yield under the combination stress treatment Th x Sh was observed in N-22. Based on morpho-physiological and yield parameters PTB-7 was selected as the tolerant variety under drought and saline condition and N-22 was selected as the tolerant variety under temperature and salinity condition. In experiment IV all the 20 genotypes were analyzed for the identification of reported markers linked to stress tolerance such as drought salinity and temperature. Reported microsatellite markers linked to drought, salinity and temperature were used to screen 20 rice varieties. Among the markers distinct polymorphism for temperature tolerance between temperature tolerant (N-22 and NL-44) and susceptible varieties was shown by RM 6100. RM 7076 showed distinct polymorphism in tolerant varieties PTB-7 and NL-44 . RM 1287 showed distinct polymorphism for salinity tolerance in PTB-7 and N-22. Drought tolerance between drought tolerant (PTB-7) and susceptible varieties was Shown by RM 490.
Effect of growth regulators on the growth and flowering of anthurium (Anthurium andreanum Linden)
(Department of Plant Physiology, College of Agriculture, Vellayani, 2000) Beena, R; Mercy, S T
An investigation on the effect of growth regulators on growth and flowering of Anthurium andreanum Linden was conducted in the Department of Plant Physiology, College of Agriculture, Vellayani during 1998-2000. Mature plants of three varieties of Anthurium andreanum Linden formed the material. The varieties used were Liver Red (L.R.), Ceylon Red (C.R.) and Kalympong Orange (K.O.). Three growth regulators namely Gibberellic Acid (GA), Tri Iodo Benzoic Acid (TIBA) and Kinetin (K) were used at 100 ppm, 300 ppm and 500 ppm concentrations. Two controls i.e., distilled water spray and no spray were also included. Each concentration of the growth regulator was sprayed three times at one month intervals. Observations were taken three months after the first spray and then at three months intervals, twice more. The effect of treatments on morphological floral, physiological and bio-chemical aspects was studied. Results of the experiments revealed that growth regulators had significant effect on most of the characters under study. They are listed below. ;.. Maximum plant height was obtained nine months after the first spray for K.O. treated with GA at 500 ppm (69.82 cm). ;.. Minimum plant spread (EW) - nine months afte~ the first spray was obtained for K.O. treated with TIBA at 100 ppm (28.44 cm) and minimum plant spread (NS) was recorded by K.O. - no spray (28.02 cm) in the ninth month of observation. 8J ~ Maximum number of leaves/spadices per year (9.0) was recorded by C.R. treated with GA at 300 and 500 ppm. ~ Minimum number of days (40.8) taken for successive leaf production was obtained for C.R. treated with GA at 300 and 500 ppm. ~ Highest" number of suckers/plant (4.6) was produced by K.O. treated with GA at 500 ppm, obtained nine months after the first spray. ~ The highest length of spadix (43.52 cm) was showed six months after the first spray by L.R. treated with GA at 500 ppm. ~ Largest spathe (95.4 cm2) was recorded three months after the first spray by K.O. treated with GA at 500 ppm. ~ Highest longevity of spadix (103 days) was obtained for L.R. treated with kinetin at 500 ppm. ~ Smallest candle size was obtained nine months after the first spray by the variety C.R. treated with TIBA at 500 ppm (4.1 cm). ~ Highest chlorophyll content (2.16 mg/g tissue) was recorded rune months after the first spray by K.O. treated with GA at 500 ppm. ~ Highest carotenoid content (10.41 mg/lOO g sample) was obtained six months after the first spray by L.R. treated with GA at 300 ppm. ~ Highest anthocyanin content (388.2 mg/l OOg sample) was recorded six months after the first spray by L.R. (control 1) distilled water spray. ~ Highest protein content (109 mg/ g tissue) was obtained six months after the first spray by K.O. treated with kinetin at 500 ppm. ~ Highest phenol content (121.2 mg/g tissue) was recorded three months after the first spray by K.O. treated with kinetin at 500 ppm. Based on the economics of growth regulator application, G.A. 500 ppm was the best treatment with positive profit increase in all the three varieties. This treatment achieved an enhanced profit of Rs. 133.70 per plant per year in the variety L.R., Rs. 86.30 enhanced profit in K.O. and Rs. 70.10 in the variety C.R.
Effect of high temperature on physiological, biochemical and yield parameters in tomato(Solanum lycopersicum L.)
(Department Of Plant physiology, College Of Agriculture, Vellayani, 2020) Amrutha, Vijayakumar; Beena, R
Effect of high temperature stress on seed fillings and nutritional quality of rice (Oryza sativa L.)
(Department of Seed Science and Technology, College of Agriculture, Vellayani, 2020) Kandanulu, Pravallika; Beena, R
Elucidating the role of growth promoting endophytic fungus Piriformospora indica for water stress tolerance in rice (Oryza sativa L.)
(Department of Plant Physiology, College of Agriculture ,Vellayani, 2022-03-10) Lekshmi, Mohan S; Beena, R
The research work titled “Elucidating the role of growth promoting endophytic fungus Piriformospora indica for water stress tolerance in rice (Oryza sativa L.)” carried out at Department of Plant Physiology, College of Agriculture, Vellayani during 2020-2021 with the objective to elucidate the changes in morphological, physiological, biochemical and molecular mechanisms associated with water stress tolerance in Piriformospora indica-colonised rice. The roots of Ptb 23, Ptb 24, Ptb 29 and Ptb 30 varieties’ seedlings were appraised microscopically for root colonisation after germinating in trays containing P. indica-infused composted coir pith- cow dung (1:1) mixture maintained in temperature and humidity-controlled conditions. Isolated or chains of double walled pear shaped chlamydospores were observed in the root sections of seedlings in trays with P. indica after seven days of cocultivation. On treatment with Poly Ethylene Glycol (PEG) 6000 at concentrations of 0, 5,10, 15, and 20 per cent, the varieties on root colonisation with P. indica showed higher water stress tolerance while the water stress tolerant varieties Ptb 29 and Ptb 30 showed tolerance to water stress even in the absence of P. indica. Shoot length, shoot and root dry weight, number of root branches, SVI 1 and SVI 2 increased in P. indica-colonised plants than non-colonised plants under water stressed condition, while the root length decreased. Based on the observations on different parameters, Ptb 29 was considered as the best water stress tolerant variety and as Ptb 23 performed better than Ptb 24 under water stress condition, the former was selected as the best water-stress susceptible variety. The P. indica-colonised and non-colonised rice seedlings of Ptb 23 and Ptb 29 were the evaluated for water stress tolerance during the different growth stages by studying the morphological, physiological, biochemical, yield parameters and molecular aspects. P. indica-colonised plants under water stress exhibited higher shoot and root length, shoot and root dry weight, root-shoot ratio and root volume, however, it was more conspicuous in the water stress susceptible variety. The enhanced plant shoot-root growth and biomass production as well as other changes in plant morphology after P. indica-colonisation can be related to the plant response to increase auxin level in roots either produced by the fungus or by the plant due to stimulation by the endophyte. Relative water content was found to be higher in water stressed P. indica-colonised plants in both Ptb 23 and Ptb 29, although the effect of colonisation was more visible in Ptb 23. There was significant increase in the specific leaf area in P. indica-colonised plants of both varieties than non-colonised plants. In the current study, rice plants of Ptb 29 under water stressed condition had higher cell membrane stability index than Ptb 23. Plants in the presence of P. indica showed significantly reduced MDA content which indicates that P. indica lowers the adverse consequences of drought. Ptb 29 had lower MDA content than Ptb 23, which further established that Ptb 29 is more tolerant to water stress. Gas exchange parameters like stomatal conductance, transpiration rate and photosynthetic rate showed increase in P. indica-colonised plants than in non-colonsed plants. Retention of chlorophyll was significantly higher in water stressed plants of Ptb 29 than Ptb 23. The increased activity of antioxidant enzymes such as superoxide dismutase and catalase in P. indica-colonised plants during stressed condition reduced ROS levels in cells and thereby minimizing or preventing damage to cellular components. P. indica-colonised plants showed a reduced invertase activity than non-colonised plants. P. indica-colonisation improved the number of tillers, productive tillers as well the panicle length in plants under water stressed condition. The spikelet sterility was higher in non-colonised and water stressed plants. P. indica-colonisation contributed to a considerable increase in grain weight in Ptb 23. All these factors contributed to the final yield of the plant and unsurprisingly, P. indica-colonised plant sets produced more yield than non-colonised plant sets under water stressed conditions. Even though Ptb 29 produced more yield., P. indica-colonisation was more noticeable and effective in the water stress susceptible variety- Ptb 23. Keeping in view of our results, it can be emphasised that P. indica can mitigate the ill effects of water stress. The findings obtained from this study can be used as a foundation for future lines of research related to rational improvement of rice plants against water stress using endophytes.
Identification of microsatellite markers associated with root traits for drought tolerance in rice (Oryza sativa L.)
(Department of Plant Technology, College of Agriculture, Vellayani, 2017) Rejeth, R; Beena, R
Identification of molecular markers and quantitative trait loci(QTLs)associated with drought tolerant and plant production traits in rice(Oryza sativa L.)using association genetic analysis
(Department Of Plant physiology, College Of Agriculture, Vellayani, 2020) Nithya, N; Beena, R
Identification of simple sequence repeat (SSR) markers linked to high temperature tolerance in rice (Oryza sativa L.) by bulked segregant analysis
(Department of Molecular Biology and Biotechnology, College of Agriculture, Vellayani, 2023-08-24) Aparna, K.; Beena, R
The study entitled “Identification of Simple Sequence Repeat (SSR) markers linked to high temperature tolerance in rice (Oryza sativa L.) by bulked segregant analysis” was conducted at the Department of Molecular Biology and Biotechnology and the Department of Plant Physiology, College of Agriculture, Vellayani, Thiruvananthapuram during 2022-23. The objective of the study was to evaluate the F3 population of Uma X NERICA-L-44 for identifying SSR markers linked to high temperature tolerance in rice by bulked segregant analysis and to establish the role of the genes associated with them in heat tolerance. Seeds collected from 46 F2 segregants (23 tolerant and 23 susceptible) of Uma X NL-44 along with their parents were raised and transplanted to pots after 18 days of sowing in the Kharif season of 2022. These 48 lines were kept under normal conditions up to the maximum tillering stage and then transfered to polyhouse conditions where it was subjected to a high temperature of 38-40 ⁰C. Phenotypic evaluation was done for plant height, tiller number, productive tiller number, days to flowering, time of anthesis, Pollen viability, Spikelet fertility, and 100 seed weight. Based on spikelet fertility percentage, 10 extremely tolerant and 10 extremely susceptible lines were selected. DNA was extracted from the selected 10 heat tolerant and 10 susceptible lines along with the parents by the modified Cetyltrimethylammoniumbromide (CTAB) method of DNA extraction. The quality and quantity of extracted DNA were checked by using agarose gel electrophoresis and spectrophotometric analysis. The DNA samples were screened by using 55 SSR primers distributed across the rice genome. Out of 55 SSR primers, 18 of them showed polymorphism between the parents. Then equal quantity of DNA was pooled to make heat tolerant and susceptible bulks. The bulked DNA samples were screened using the 18 SSR primers that have shown polymorphism between parents. The polymorphic markers between the tolerant and susceptible bulks were used to study the segregation of the alleles in the individual lines constituting the tolerant and susceptible bulks. Through bulked segregant analysis (BSA), 10 SSR markers were found polymorphic between tolerant and susceptible bulks and their individual lines. It revealed the possible presence of genetic loci for heat tolerance in those locations. Out of the 10 SSR markers identified in the BSA (RM337, RM10793, RM242, RM5749, RM6100, RM490, RM3475, RM470, RM473, and RM556), nine of the markers have been previously reported for heat tolerance traits. RM337 is newly identified in the present study. The genes in the 200 kb vicinity of the RM markers were retrieved from the Rice Annotation Project database. To get a deeper insight into how these genes participate in heat tolerance, gene annotation, gene ontology (GO) enrichment analysis, and trait ontology (TO) were performed for all the significant markers. Upon screening of the loci in the proposed region, genes LOP1 (LOC_Os08g01330) and LOP2 (LOC_Os08g0112) were found to be associated with RM337. LOP1 is a NAC transcription factor that is reported to be involved in the regulation of cellulose synthesis, secondary wall biosynthesis (Os08t0103900-01), and inflorescence development. LOP2 is also known as OsMOT1, which is a molybdate transporter involved in the uptake and translocation of molybdate (Os08t0101500-01). Hence their expression was analyzed in the two rice varieties under both control and high temperature conditions. LOP1 was found to be significantly upregulated in the NL-44 variety under high temperature condition compared to the normal temperature conditions and susceptible variety, Uma. On the other hand, the gene LOP2 was found to be upregulated in both varieties under the higher temperature condition compared to their respective controls. However, the relative expression in Uma was higher than in NL-44. In the present study, the phenotypic evaluation and bulked segregant analysis using 55 SSR primers in F3 generation of Uma X NL-44 revealed that 10 SSR markers (RM222, RM242, RM337, RM470, RM473, RM490, RM556, RM5749, RM6100, RM10793) are linked to high temperature tolerance in rice. The newly identified SSR marker RM337 and associated gene LOP1 is also linked to high temperature tolerance in rice. The results demonstrate that BSA using SSR markers and gene annotation and enrichment analysis is useful in identifying genomic regions and genes that contribute to thermotolerance respectively. Also, these F3 lines can be used for the development of high temperature tolerant rice varieties and these markers can be used for marker assisted selection (MAS) in rice.
Impact of foliar application of plant growth regulators and nutrients on high temperature stress mitigation in rice (oryza stavia L)
(Department of Plant Physiology, College of Agriculture, Vellayani, 2019) Raghunath, M P; Beena, R
The study entitled “Impact of foliar application of plant growth regulators and nutrients on high temperature stress mitigation in rice (Oryza sativa L.)” was conducted in the Department of Plant Physiology, College of Agriculture, Vellayani during August to December of 2018 with the objectives to study the effect of foliar application of plant growth regulators and nutrients on high temperature mitigation and to advance the flowering time by using methyl jasmonate (MeJA) in rice. The investigation comprised two experiments. The extent of variation for various physiological, biochemical, morphological and yield parameters were assessed as an indicator of high temperature stress mitigation by using plant growth regulators and nutrients. The rice variety (Uma) utilized in the experiment was collected from IFSRS, Karamana. Plants were maintained under high temperature condition in a temperature controlled polyhouse from seedling to maturity stage with three replications. Maximum and minimum temperatures were measured daily using a thermo-hygrometer. The first experiment was laid out in CRD with 10 treatments [Brassinosteroid (BR)-50 ppm, Boron (B)-100 ppm, Calcium chloride (CaCl2)-0.6 per cent, Salicylic acid (SA)-50 ppm, Glycine betaine (GB)-20 ppm, Pink- Pigmented Facultative Methylotrophs (PPFM)-1 per cent, 1-methyl cyclopropane (1-MCP)-50 ppm, Gibberllic acid (GA3)-50 ppm, water spray and control (no spray)] were sprayed at panicle initiation, heading and flowering stage. Physiological observations and yield parameters were recorded at 50 per cent flowering and harvesting stage respectively. The study revealed that physiological and biochemical parameters such as cell membrane stability index (%), photosynthetic rate (μmol CO2 m-2 s-1), stomatal conductance (mmol H2O m-2 s-1) and Fv/Fm ratio were found to increase significantly in most of the treatments under high temperature stress condition, whereas leaf temperature(°C) and transpiration rate (mmol H2O m-2 s-1) decreased. Among the treatments, BR spray significantly increased in the cell membrane stability index (141.57%), photosynthetic rate (17.50 μmol CO2 m-2 s-1), stomatal conductance (583.70 mmol H2O m-2 s-1), Fv/Fm ratio (0.74), chlorophyll stability index (109.32%), chlorophyll a/b ratio (1.28) and superoxide dismutase activity (0.33 activity g-1 min-1). Treatments had significant effect on morphological and yield parameters over control plants. Among the treatments, GA3 spray resulted in significant increase in plant height (142.75 cm) and panicle length (21.33 cm). BR spray significantly increased the productive tillers per plant (10.25), pollen viability (80.23%), spikelet fertility percentage (75.4%) and grain yield per plant (15.87 g). The second experiment was laid out in CRD with 10 treatments. Foliar spray of MeJA in varying concentrations was given on spikelet at different time [2mM L-1 MeJA at 7 am, 2mM L-1 MeJA at 8 am, 2mM L-1 MeJA at 9 am, 4mM L-1 MeJA at 7 am, 4mM L-1 MeJA at 8 am, 4mM L-1 MeJA at 9 am, water spray at 7 am, water spray at 8 am, water spray at 9 am and control (no spray)]. Physiological observations were taken at 50% flowering stage and yield parameters were taken at harvesting stage. The study revealed that among the treatments, 4mM L-1 MeJA at 7 am treatment showed early anthesis (08:11 am) and also significant increase in pollen viability (61.93%), spikelet fertility (56.07%), yield per plant (8.55 g) and 1000 grain weight (21.33 g). In the first experiment there was significant variation for physiological, biochemical, morphological and yield components among treatments. BR treatment recorded high pollen viability, spikelet fertility and grain yield per plant by improving the physiological and biochemical traits such as cell membrane stability index, photosynthetic rate, stomatal conductance, Fv/Fm ratio, chlorophyll stability index, chlorophyll a/b ratio and superoxide dismutase activity. Hence, BR treatment can mitigate the ill effects of high temperature stress in rice. In the second experiment there was significant variation for physiological and yield components among treatments. 4mM L-1 MeJA at 7 am showed better performance for all the parameters such as anthesis time, pollen viability, spikelet fertility, yield per plant and 1000 grain weight. Hence, MeJA can advance anthesis time thereby enabling plants to escape from the severe temperature experienced at normal flowering time.
Impact of seed exposure to simulated microgravity on growth and development in tomato (Solanum lycopersicum L.)
(Department of Seed Science and Technology, College of Agriculture, Vellayani, 2025-02-12) Ram Ambiya; Beena, R
The study titled “Impact of seed exposure to simulated microgravity on growth and development in tomato (Solanum lycopersicum L)” was undertaken with the objective to evaluation of morpho-physiological, anatomical and biochemical changes in growth and development in tomato after exposure of seeds to different simulated microgravity. The experiments were conducted using seeds of the tomato variety 'Anagha,' which were exposed to simulated microgravity conditions. Microgravity is characterized by a reduction in gravitational force, which can create stress in organisms and plants, affecting their metabolism, growth, and development. Simulated microgravity was created using a Random Positioning Machine (RPM), which rotates seeds slowly at speeds of (25-40 rpm), reducing the effect of gravity to around 10-3 g. Seeds were exposed to (4hr, 8hr, 12hr, 24hr and control different durations of simulated microgravity. Two experiments were carried out in a completely randomized design (CRD). In both experiments, the seeds were sown, and the seedlings were transplanted into pots 30 days after sowing. They were maintained under standard cultural practices, including irrigation. The study was conducted across two growing seasons: Summer and Kharif. The results revealed that exposure to simulated microgravity significantly influenced tomato growth. The simulated microgravity treatment (T4) enhanced the germination rate, which reached (95%) in the summer and (97%) in the kharif season by the seventh day. Additionally, treatment (T3) exhibited the highest seedling vigor in the summer (13.75), while treatment T4 showed the highest seedling vigor in the kharif season (15.32). Moreover, treatment T4 also displayed the highest germination speed in both seasons. In the summer, the earliest flowering occurred in treatment T4 (23.5 DAT), while in the kharif season, treatment T3 exhibited early flowering (24.75 DAT). The pollen viability in treatment T4 was enhanced, exceeding (80%) during the kharif season. Furthermore, the study reported an increase in chlorophyll content under simulated microgravity conditions, with treatment T4 reaching (1.785 mg/g) in the kharif season. Various enzymatic activities, such as peroxidase, superoxide dismutase, and catalase, increased, while malondialdehyde (a marker of lipid peroxidation) also increased. These responses suggest that the plants developed better stress tolerance under microgravity conditions. The study found that simulated microgravity significantly influenced various growth and biochemical parameters in tomato plants. In the summer season, treatment T1 showed the highest ascorbic acid content (12.62 mg g-1), plant height (87.175 cm), fresh weight (378.75 g), and root growth. In the kharif season, treatment T3 exhibited the highest ascorbic acid content (20.37 mg/g-1), anthocyanin (0.448 mg/g), and total sugar content (1.305 mg/g), while treatment T4 had the highest lycopene content (3.143 µg/g), plant height (98.4 cm), and yield (842.25 g). Root length, volume, fresh, and dry weight were significantly enhanced under treatment T3 in the kharif season. Overall, seeds exposed to simulated microgravity showed increased growth, improved biochemical composition, and enhanced fruit yield, highlighting the potential of microgravity as a tool for crop improvement in both terrestrial and extraterrestrial agriculture. In conclusion, this study demonstrates that simulated microgravity has a positive impact on the growth, development, and biochemical characteristics of tomato plants. Improved germination rates, enhanced seedling vigor, increased chlorophyll content, and higher yields were observed, suggesting that microgravity could be a useful tool for crop improvement. Furthermore, increased enzymatic activity and better root growth under stress conditions indicate the potential applications of simulated microgravity in agriculture, both on land. This is the first of its kind of study performed on Anagha seeds and such studies on other species developed within KAU can lead to interesting results and important clues on enhancing crop yield and productivity. Future research should focus on long-term exposure to simulated microgravity and its effects on other crop species. This knowledge can help optimize crop production in space missions and challenging terrestrial environments, contributing to sustainable food security on earth and beyond.
Impact of seed exposure to simulated microgravity on growth and development in tomato (Solanum lycopersicum L.)
(Department of Seed Science and Technology, College of Agriculture, Vellayani, 2025) Ram Ambiya.; Beena, R
The study titled “Impact of seed exposure to simulated microgravity on growth and development in tomato (Solanum lycopersicum L)” was undertaken with the objective to evaluation of morpho-physiological, anatomical and biochemical changes in growth and development in tomato after exposure of seeds to different simulated microgravity. The experiments were conducted using seeds of the tomato variety 'Anagha,' which were exposed to simulated microgravity conditions. Microgravity is characterized by a reduction in gravitational force, which can create stress in organisms and plants, affecting their metabolism, growth, and development. Simulated microgravity was created using a Random Positioning Machine (RPM), which rotates seeds slowly at speeds of (25-40 rpm), reducing the effect of gravity to around 10-3 g. Seeds were exposed to (4hr, 8hr, 12hr, 24hr and control different durations of simulated microgravity. Two experiments were carried out in a completely randomized design (CRD). In both experiments, the seeds were sown, and the seedlings were transplanted into pots 30 days after sowing. They were maintained under standard cultural practices, including irrigation. The study was conducted across two growing seasons: Summer and Kharif. The results revealed that exposure to simulated microgravity significantly influenced tomato growth. The simulated microgravity treatment (T4) enhanced the germination rate, which reached (95%) in the summer and (97%) in the kharif season by the seventh day. Additionally, treatment (T3) exhibited the highest seedling vigor in the summer (13.75), while treatment T4 showed the highest seedling vigor in the kharif season (15.32). Moreover, treatment T4 also displayed the highest germination speed in both seasons. In the summer, the earliest flowering occurred in treatment T4 (23.5 DAT), while in the kharif season, treatment T3 exhibited early flowering (24.75 DAT). The pollen viability in treatment T4 was enhanced, exceeding (80%) during the kharif season. Furthermore, the study reported an increase in chlorophyll content under simulated microgravity conditions, with treatment T4 reaching (1.785 mg/g) in the kharif season. Various enzymatic activities, such as peroxidase, superoxide dismutase, and catalase, increased, while malondialdehyde (a markerof lipid peroxidation) also increased. These responses suggest that the plants developed better stress tolerance under microgravity conditions. The study found that simulated microgravity significantly influenced various growth and biochemical parameters in tomato plants. In the summer season, treatment T1 showed the highest ascorbic acid content (12.62 mg g-1), plant height (87.175 cm), fresh weight (378.75 g), and root growth. In the kharif season, treatment T3 exhibited the highest ascorbic acid content (20.37 mg/g-1), anthocyanin (0.448 mg/g), and total sugar content (1.305 mg/g), while treatment T4 had the highest lycopene content (3.143 μg/g), plant height (98.4 cm), and yield (842.25 g). Root length, volume, fresh, and dry weight were significantly enhanced under treatment T3 in the kharif season. Overall, seeds exposed to simulated microgravity showed increased growth, improved biochemical composition, and enhanced fruit yield, highlighting the potential of microgravity as a tool for crop improvement in both terrestrial and extraterrestrial agriculture. In conclusion, this study demonstrates that simulated microgravity has a positive impact on the growth, development, and biochemical characteristics of tomato plants. Improved germination rates, enhanced seedling vigor, increased chlorophyll content, and higher yields were observed, suggesting that microgravity could be a useful tool for crop improvement. Furthermore, increased enzymatic activity and better root growth under stress conditions indicate the potential applications of simulated microgravity in agriculture, both on land. This is the first of its kind of study performed on Anagha seeds and such studies on other species developed within KAU can lead to interesting results and important clues on enhancing crop yield and productivity. Future research should focus on long-term exposure to simulated microgravity and its effects on other crop species. This knowledge can help optimize crop production in space missions and challenging terrestrial environments, contributing to sustainable food security on earth and beyond.
Impact of seed priming on psychological and biochemical mechanisms under water stress condition in chilli (Capsicum annuum L.)
(Department of Seed Science and Technology, College of Agriculture , Vellayani, 2023-12-16) Madamsetty Phani Kumar; Beena, R
A study entitled “Impact of seed priming on physiological and biochemical mechanisms under water stress condition in chilli (Capsicum annuum L)” was undertaken with the objective assessment of the effect of seed priming on physiological and biochemical mechanisms and yield components under water stress condition in chilli. For both experiments I & II seeds of the chilli variety ‘Vellayani Anugraha’ were primed with 2.5% potassium nitrate (KNO3), 3% silicon dioxide (SiO2), and unprimed were soaked in distilled water for 24 hours and subjected to control and water stress levels at flowering stage. The first experiment was carried out in a factorial completely randomized design (FCRD) with the first factor being stress levels and the second-factor being priming agents using different solutions replicated thrice. The seeds primed with 2.5% KNO3, 3% SiO2, and unprimed seed treatments were sown in protrays. Seedlings were transplanted to pots 35 days after sowing (DAS), irrigation, and other cultural practices were followed according to KAU POP (package of practices). Water stress was induced by withholding irrigation for three days where the relative water content (RWC) of leaves reached 70% during the flower initiation stage. The results of the first experiment revealed that seeds primed with 3% SiO2 resulted in early flowering and first fruiting. Under water stress conditions, seeds primed with 2.5% KNO3 recorded significantly higher values for RWC (69%), cell membrane stability Index (CMSI) (42.16%), malonaldehyde (0.62 μmole ml-1), H2O2 (0.62 μmol g-1), trehalose (0.15 μmol g-1 FW), α-amylase activity (14.68 μmol maltose formed min-1 mL-1), specific leaf area (15.99 cm2 g-1) total chlorophyll content (TCC) (1.92 mg g-1), superoxide dismutase (SOD) (491.3 units mg-1 of protein), total soluble sugars (TSS) (1.53 mg/g) and total soluble protein (TSP) (1.017 mg g-1) however 3% SiO2 primed seeds recorded significantly higher values for total proline content (3.12 μmoles of proline g-1 of tissue). 136 Under control conditions, 2.5% KNO3 primed seeds recorded significantly high values for RWC (92%), trehalose (0.17 μmol g-1 FW), α-amylase activity (16.76 μmol maltose formed min-1 mL-1), specific leaf area (20.88 cm2 g-1) total chlorophyll content (TCC) (4.54 mg g-1), superoxide dismutase (SOD) (491.32 units mg-1 of protein), total soluble sugars (TSS) (3.22 mg g-1) and total soluble protein (TSP) (2.06 mg g-1) however 3% SiO2 primed seeds recorded significantly higher values for total proline content (1.31 μmoles of proline/g of tissue) and CMSI (91.0%). Under water stress conditions, capsaicin content was recorded higher in seeds primed with 2.5% KNO3 (144.6 μg g-1), and ascorbic acid was recorded the highest in seeds primed with 3% SiO2 (3.89 mg g-1). In contrast, in control, both capsaicin content (224.0 μg g-1) and ascorbic acid content (4.81 mg g-1) were recorded higher in seeds primed with 2.5% KNO3. Under water stress conditions, the yield components were higher in seeds primed with 2.5% KNO3. The plant height (60 cm), number of flowers plant-1 (24 number), number of fruits plant-1 (20 number), and fruit yield (44.29 g), were recorded as significantly higher in seeds primed with 2.5% KNO3. however, the seed yield (3.60 g) was recorded as significantly higher in seeds primed with 3% SiO2, and the number of flowers plant-1 (22 number) was found the highest in unprimed seeds. Whereas in control, 2.5% KNO3 primed seeds recorded significantly higher plant height (65.3 cm), fruit yield (90.4 g), number of fruits plant-1 (23.4), and 3% SiO2 primed seeds recorded significantly higher seed yield (4.03g). The second experiment was carried out in a factorial randomized block design (FRBD) with the first factor being stress levels and the second factor being priming using different solutions which were replicated thrice. the seeds primed with 2.5% KNO3, 3% SiO2, and unprimed seeds treatments were sown in protrays. Seedlings were transplanted to the field 35 days after sowing (DAS) and irrigation and other cultural practices were followed according to KAU POP. Water stress was induced by withholding irrigation for seven days where the (RWC) of leaves reached 70% during the flower initiation stage. During this period, physiological parameters were taken from the stress and control plants. The results revealed that seeds primed with 3% SiO2 recorded early flowering whereas seeds primed with 2.5% KNO3 recorded the first fruiting stage. Under water stress conditions, seeds primed with 2.5% KNO3 recorded significantly high values for RWC (68.16%), CMSI (46.66%), malonaldehyde (0.73 μmole ml-1), H2O2 (0.71 μmol g-1), trehalose (0.13 μmol g-1 FW), α-amylase activity (13.93 μmol maltose formed min-1 mL-1), Specific leaf area (13.47 cm2 g-1) TCC (1.93 mg g-1), SOD (520.03 units mg-1 of protein), TSS (1.55 mg g-1) and TSP (1.05 mg g-1) where 3% SiO2 primed seeds recorded significantly higher values for total proline content (3.12 μmoles of proline g-1 of tissue). For control conditions, 2.5% KNO3 primed seeds recorded significantly high values for (RWC) (79 %), trehalose (0.17 μmol g-1 FW), α-amylase activity (14.77 μmol maltose formed min-1 mL-1), Specific leaf area (18.47 cm2g-1) TCC (3.86 mg g-1), SOD (405.60 units mg-1 of protein), TSS (3.16 mg/g) and TSP (2.0 mg/g) however 3% SiO2 primed seeds recorded significantly higher values for total proline content (1.31 μmoles of proline/g of tissue) CMSI (91.16%).Under water stress conditions, capsaicin content was recorded higher in seeds primed with 2.5% KNO3 (90.5 μg g-1), and ascorbic acid was recorded the highest in seeds primed with 3% SiO2 (3.78 mg g-1). In control, capsaicin content (232.0 μg g-1) and ascorbic acid content (4.75 mg g-1) were recorded higher in seeds primed with 2.5% KNO3.Under water stress conditions, the yield components were recorded as higher in seeds primed with 2.5% KNO3 like plant height (55 cm), number of flowers plant-1 (22.8 number), number of fruits plant-1 (19 number), and the fruit yield (45.3 g), were recorded as significantly higher in seeds primed with 2.5% KNO3. The seed yield (3.16g) was recorded as significantly higher in seeds primed with 3% SiO2, under, the control condition, 2.5% KNO3 primed seeds recorded significantly higher plant height (60 cm), fruit yield (84.93 g), number of fruits plant-1 (22.4) and 3% SiO2 primed seeds recorded significantly higher seed yield (3.18 g). According to our results, seed priming with 2.5% KNO3 and 3% SiO2 enhanced the capacity of the plant to absorb water by preserving the least amount of cell damage and shielding the macromolecular structures from membrane damage, Thus, seed priming with 2.5% KNO3 and 3% SiO2 can be recommended.
Impact of water stress on sucrose metabolism in rice (oryza sativa L.)
(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2021) Anie Thomas; Beena, R
The study entitled “Impact of water stress on sucrose metabolism in rice (Oryza sativa L.)” conducted at Department of Plant Biotechnology and Department of Plant Physiology, College of Agriculture, Vellayani during 2020-21. The objective was to study the impact of water stress on sucrose metabolism by analyzing the physiological and biochemical parameters and gene expression in selective drought tolerant and susceptible rice genotypes. In this study, two rice varieties, drought tolerant variety, PTB 7 (Parambuvattan) and drought susceptible, PTB 23 (Cheriya Aryan) were grown in pot culture and after the panicle initiation stage, crops were subjected to water stress by withdrawing irrigation until the plants experienced the symptoms of stress (leaf rolling). Then the various physiological parameters were studied five days after the induction of water stress. Extraction and estimation of sucrose metabolizing enzymes such as invertase, α- and β-amylase were done five days after induction of stress spectrophotometrically. Expression levels of sucrose synthase (SuSy) and sucrose transporter gene (SUC2) were analyzed from both root and leaf seven days after induction of water stress. Under water stress, physiological parameters such as cell membrane stability index, relative water content and yield trait like number of productive tillers were significantly reduced, activity of enzymes such as invertase, α- and β-amylase were increased and gene expression level of sucrose synthase (SuSy) and sucrose transporter (SUC-2), which are associated with the sucrose metabolism were upregulated. Water stress enhanced the sucrose content and reducing sugar content in rice plant. There was significant increase in root traits in PTB 7 but they were reduced in PTB 23. Also, there was a reduction in shoot biomass than the root biomass in tolerant rice variety, which leads to an increase in root to shoot (R/S) ratio. In this study, sucrose metabolism and transport were increased in both drought tolerant and susceptible variety under water stress condition. However, PTB 7 (drought tolerant) showed an improved sucrose metabolism than PTB 23 (drought susceptible) during water stress condition.
Molecular characterization and construction of population structure of selected tomato genotypes (Solanum lycopersicum L.) under high temperature stress condition
(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2020) Shanija Shaji; Beena, R
The study entitled "Molecular characterization and construction of population structure of selected tomato genotypes (Solanum lycopersicum L.) under high-temperature stress conditions” was undertaken during 2019-20 at the Department of Plant Physiology, College of Agriculture, Vellayani. The study was undertaken to evaluate the molecular variation between different tomato genotypes using simple sequence repeat (SSR) markers and the construction of the population structure of tomato genotypes. Tomato (Solanum lycopersicum) is the second most important vegetable crop, cultivated worldwide in both temperate and tropical regions. High-temperature stress is one of the major abiotic stress affecting tomatoes and significantly reducing their fruit yield and quality. Molecular markers linked to high temperature can be used for marker-assisted selection for high-temperature tolerance in tomato genotypes. Hence the present study was focused on the identification of molecular markers linked to high-temperature tolerance in tomato. The study included an experiment, in which twenty two tomato genotypes (KAU released varieties, NBPGR accessions including wild relatives of tomato) were raised in pot trays and the genomic DNA from one-month-old leaf samples was isolated by CTAB method. The quality and quantity of the isolated DNA from the twenty-two genotypes were analyzed. After checking the quality and quantity of DNA samples, they were screened using twenty-five microsatellite primers. PCR reaction was carried out using 25 selected primers of which 3 primers SSR 80, SSR 331, SSR 341 did not show any amplification and hence they were not used for further analysis. Out of the twenty-two; fifteen SSR markers viz., SSR450, SSR 602, SSR20, SSR111, SSR70, SSR 124, SSR 293, SSR 19, SSR115, SSR 304, SSR 276, SSR 47, SSR 75, SSR 134 and SSR 4 amplified monomorphic banding patterns, hence they were not considered for further analysis. Seven markers were thus selected for final analysis. The polymorphic 114 markers for temperature tolerance were SSR 96, SSR 63, SSR 13, SSR 270, SSR 356, SSR 605, and SSR 248. Among the 7 SSR markers, distinct polymorphic bands for temperature tolerance was shown by markers SSR 63 and SSR 96. The value of polymorphic information content (PIC) is commonly used in genetics, which provides an estimate of the discriminatory power of a locus or loci, taking into account not only the number of alleles expressed but also the relative frequencies of those alleles, and is a measure of polymorphism for the locus marker used in linkage analysis. The PIC values for polymorphic markers ranged from 0 to 0.65. The primers which showed the highest PIC values were SSR96 (0.65) followed by SSR63 and SSR 248 (0.612). The population structure of the 22 genotypes was performed using the Bayesian model-based scoring software STRUCTURE v2.3.4. Structure analysis divided the 22 genotypes into four subpopulations, in which tolerant genotypes were grouped into one sub-population, whereas the moderately tolerant, susceptible genotypes, genotypes which showed mixed characteristics were grouped into separate sub-populations. The presence of a band was scored as 1 and absence was scored as 0. In the NTedit program of NTSYSpc (Numerical Taxonomy SYStem) version 2.10 software, binary data generated for all varieties for the polymorphic markers were entered. The phylogenetic tree was constructed using UPGMA (Un-weighted pair group method with arithmetic mean) using NTSYSpc cluster analysis software, resulted in the dendrogram and divided the 22 tomato genotypes into four major clusters. The pattern of grouping genotypes into the clusters was similar to that in the study of the population structure. Phenotypic data of the same genotypes were collected from the Department of Plant Physiology, College of Agriculture, Vellayani was utilized for the interpretation of molecular data, the grouping of genotypes obtained from population structure and cluster analysis. Based on the interpretation of all the data obtained, among the 22 tomato genotypes; Kashi Vishesh, Anagha, Vellayani Vijay 115 were grouped as tolerant varieties. IIHR-2200, Manuprabha, Akshaya were categorized as moderately tolerant varieties. Varieties that showed mixed characteristics were Nandi, Vaibhav, Pusa Ruby, Manulakshmi, Arka Alok, Sakthi, IIHR-26372, Arka Vikas, Arka Abha, IC-45, Arka Samrat and PKM-1. Genotypes that were categorized as susceptible varieties were Arka Saurabh, Pusa Rohini, Palam Pride, and Arka Rakshak. Among the markers, distinct polymorphism for temperature tolerance between temperature tolerant (Kashi Vishesh, Anagha, and Vellayani Vijay) and susceptible varieties (Arka Saurabh, Pusa Rohini, Palam Pride, and Arka Rakshak) was shown by SSR 63 and SSR 96.
Molecular characterization of rice genotypes having Variability in heat tolerance
(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2017) Neethu V Mohan; Beena, R
The study entitled “Molecular characterization of rice genotypes having variability in heat tolerance” was conducted at the Department of Plant Physiology, College of Agriculture, Vellayani, Thiruvananthapuram. Rice (O. sativa) is very sensitive to high temperature especially at the reproductive and grain filling stage which leads to higher spikelet sterility and ultimately yield losses. The present investigation was, therefore, carried out with the objective to study the variation in rice genotypes for heat tolerance using microsatellite markers. In the present study, a set of 50 SSR primers were employed to assess the genetic diversity among the 10 genotypes. Out of 50 markers, 11 markers showed polymorphism, the marker RM6100 was found as a functional marker associated with heat tolerance in rice, and is functional for further crop breeding programmes. A dendrogram was generated with the aim of analyzing the relationships between the 10 genotypes tested. The genetic similarity index ranged from 0.1 to 0.833. The lowest value 0.1was obtained between PTB7 and CR Dhan202 while highest similarity value (0.833) calculated was between the PTB7 and CR Dhan204 genotypes. However, the genetic diversity analysis with SSR markers will contribute to maximize the selection of diverse parents in the future rice breeding program or development of heat tolerant cultivars.
Physiological and anatomical plasticity of root traits under water stress and molecular characterization using root specific genes in rice
(Department of Plant Pathology, College of Agriculture, Vellayani, 2019) Lakshmi Naga Manikanda Chennamsetti; Beena, R
The study entitled “Physiological and anatomical plasticity of root traits under water stress and molecular characterization using root specific genes in rice (Oryza sativa L.)” was conducted in the Department of Plant Physiology, College of Agriculture, Vellayani during October – January, 2017-19 with the objective to quantify the adaptive plasticity in root-shoot morphology, physiology and root anatomical plasticity under water stress in selected rice genotypes and molecular characterization using root specific genes. The extent of variation for various physiological, biochemical and anatomical characters were assessed as an indicator of water stress from six selected genotypes collected from RARS Pattambi and N-22 from IIRR, Hyderabad. Plants were maintained under 100% and 50% field capacity (FC) soil moisture in a rain out shelter. A set of five replications were maintained and observations were made at booting stage on root, physiological, biochemical and anatomical parameters and significant variations for these traits were noticed for tolerant and susceptible genotypes. The study revealed that parameters such as relative water content (RWC) (%), specific leaf area (cm2 g-1), and cell membrane stability index (%) were found to be decreasing but not significant under stress condition whereas root parameters, biochemical and biomass partitioning were found to be increasing among the tolerant and susceptible genotypes. The highest RWC was recorded from N-22 (85.37%) under stress condition whereas least from Ptb 35 (71.96%). N-22 showed the highest reduction in specific leaf area with 219.9 cm2 g-1 whereas Ptb 39 showed an increasing trend in specific leaf area by 1.5% with 183.73 cm2 g-1 under stress. Cell membrane stability index (%) was highest in Ptb 30 (97.10%) under stress whereas least was recorded from Ptb 39 (83.11%). Carbon isotope discrimination (Δ13C)(mil-1) was least for N-22 (21.84) (Δ13C)(mil-1) and highest in Ptb 39 (23.49) (Δ13C)(mil-1) at panicle initiation. Study on root parameters of tolerant and susceptible genotypes at two FC levels exhibited significant variation among root parameters. Root length was highest in Ptb 29 (38.46 cm) and least in Ptb 35 (20.66 cm) under water stress. Among the genotypes Ptb 29 was found to be performing better for other root characters viz., root volume, root dry weight, root/shoot ratio and specific root length whereas least performance was noticed from susceptible genotypes Ptb 35 and Ptb 39. A significant differences in biomass partitioning was noticed among the genotypes, for characters such as leaf weight ratio, stem weight ratio and root weight ratio. Under stress root weight ratio was highest in Ptb 29 (0.21) and lowest in Ptb 35 (0.106). Anatomical studies revealed significant effects at both genotype and treatment levels. Tolerant genotypes were found to be more responsive under water stress for anatomical traits. N-22 and Ptb 29 exhibited an increase in root diameter (1.55mm and 1.796 mm), stele diameter (0.49 and 0.31 mm), late metaxylem number and late metaxylem diameter (5.6, 0.069 mm and 5.6, 0.076 mm respectively. Early metaxylem number found to be increasing in tolerant genotypes N-22 (30.66) whereas susceptible genotypes exhibited declining trend. Sclerenchymatous tissue was found to be highest in N-22 (0.024mm) whereas Ptb 35 a susceptible genotype exhibited lowest value for sclerenchyma with 0.012 mm. Yield attributes were found to vary significantly among genotypes. Spikelet fertility percentage and yield per plant was highest in N-22 with 85.66% and 24.66 g respectively. 1000 grain weight was highest in Ptb 30 (27.23 g) and lowest in Ptb 39 (22.5 g). Genotyping of the selected tolerant and susceptible rice genotypes using available DEEPER ROOTING QTL specific primers and other available drought specific SSR primers was done from seedlings raised in a petri dish. It was found that DRO1 specific microsatellite markers did not exhibited polymorphism among tolerant and susceptible genotypes but another drought related SSR primer RM 518 showed polymorphism for tolerant and susceptible genotypes. Expression studies were done between one tolerant and one susceptible genotypes i.e., Ptb 29 and Ptb 35 with DEEPER ROOTING QTL specific primers and EST- SSR RM 518. Results of expression studies using RM 518 exhibited differential expression under 100% FC and 50% FC condition and also among the genotypes Ptb 29 and Ptb 35. Significant variation was observed for physio-morphological and yield components among rice genotypes under 100% FC and water 50% FC conditions. Genotypes with better root traits such as root length, root shoot ratio and root anatomical plasticity exhibited more tolerance towards drought. The tolerant genotypes i.e., N-22. Ptb 29 and Ptb 30 can be used as donor plants in breeding programs for trait introgression for developing drought tolerant cultivars. Microsatellite marker RM 518 which could distinguish drought tolerant and susceptible genotype can be used for marker assisted selection for drought tolerance in rice. A differential expression of drought related genes was seen in tolerant and susceptible genotypes under water stress condition.
Somatic embryogenesis in musa (AAB) Nendran
(Department of pomology and floriculture, College of horticulture,Vellanikkara, 2002) Beena, R; Aravindakshan, K
Validation of temperature induction response (TIR) technique for inducing drought and heat stress tolerence in rice (Oryza sativa L.)
(Department of Plant Physiology, College of Agriculture, Vellayani, 2018) Reshma Mohan; Beena, R