PG Thesis

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Subject: search.filters.subject.Plant physiology

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    Physiological effect of seed priming and foliar application of growth regulators in cowpea (Vigna unguiculata L.)
    (Department of Plant Physiology, College of Agriculture, Padannakkad, 2022-05-24) Swathy, P.; Sudarsana Rao, G V
    An investigation entitled “Physiological effect of seed priming and foliar application of growth regulators in cowpea (Vigna unguiculata L.)” was carried out in two experiments during the period 2020-2021. The objective of the study was elucidation of influence of seed priming and foliar application of growth regulators on morpho-physiological changes, yield and quality in cowpea (Vigna unguiculata L.). Experiment-1 on seed germination and early seedling growth was conducted at College of Agriculture, Padannakkad. It was carried out in complete randomized design with eight treatments and three replications. Treatments included seeds primed with growth regulators viz., thiourea @ 500 ppm (T2); salicylic acid @ 50 ppm (T3); salicylic acid @ 100 ppm (T4); salicylic acid @ 150 ppm (T5); brassinolide @ 0.1 ppm (T6); brassinolide @ 0.3 ppm (T7); brassinolide @ 0.5 ppm (T8) and control (T1) without growth regulators. Minimum number of days taken for 50 per cent seed germination in T4, T6 and T7. 100 per cent seed sprouting and seed germination were recorded in T4 and T7. Maximum seedling survival was recorded in T4 and T7 which was on par with T5 and T6. Whole seedling dry weight and seedling vigour index were significantly enhanced in T7 followed by T4. Based on statistical analysis T4 and T7 were considered as best treatment for further field studies. Experiment-2 was conducted as field study at Instructional Farm II, Karuvacheri, College of Agriculture, Padannakkad. The best seed priming results obtained from Experiment -1 were further studied under field condition in Experiment- 2. It included 14 treatments viz., Standard POP recommendation without thiourea (KAU, 2016) (T1); standard POP with thiourea foliar spray @ 500 ppm (T2); T₁ + salicylic acid foliar spray @ 50 ppm (T3); seed priming with 100 ppm salicylic acid + salicylic acid foliar spray @ 50 ppm (T₄); T₁ + salicylic acid foliar spray @ 100 ppm (T₅); seed priming with 100 ppm salicylic acid + salicylic acid foliar spray @ 100 ppm (T₆); T₁ + salicylic acid foliar spray @ 150 ppm (T₇); seed priming with 100 ppm salicylic acid + salicylic acid foliar spray @ 150 ppm (T₈); T₁ + brassinolide foliar spray @ 0.1 ppm (T9); seed priming with 0.3 ppm brassinolide + brassinolide foliar spray @ 0.1 ppm (T₁₀); T₁ + brassinolide foliar spray @ 0.3 ppm (T₁₁); seed priming with 0.3 ppm brassinolide + brassinolide foliar spray @ 0.3 ppm (T₁₂); T₁ + brassinolide foliar spray @ 0.5 ppm (T₁₃) and seed priming with 0.3 ppm brassinolide + brassinolide foliar spray @ 0.5 ppm (T₁₄). The foliar sprays were given at 20 and 40 DAS. Regarding morphological observations, T6 and T14 significantly superior in plant height, leaf area per plant and number of compound leaves per plant at 25, 45 and 60 DAS. Minimum number of days taken for 50 per cent flowering in T₁₄ which was on par with T6. Minimum number of days for first harvest were recorded in T6 and T₁₄. Duration of crop and greater number of productive flower setting were significantly superior in T14 and T6 which was on par with T12. Efficient translocation of assimilates increased pod length and pod diameter in T6 which was on par with T14. Leaf area index and SPAD chlorophyll meter readings were maximum in T6 and T14 at 25, 45 and 60 DAS. The increase in net photosynthetic area and assimilate translocation, enhanced the total dry matter production, relative growth rate and crop growth rate in T14 followed by T6 during vegetative stage and reproductive stage as well. Maximum relative leaf water content was observed in T6 which was on par with T5, T8, T12 and T14 at 25 DAS and T5, T8, T12, T13 and T14 at 60 DAS. The ratio of variable fluorescence to maximum fluorescence (Fv/Fm) was recorded maximum in T14 which was on par with T6 and T12 at 25 DAS. The maximum effective quantum yield of PS II (Y (II)) were recorded maximum in T6 and T14 which were on par with T10 and T12 at 25 DAS. At 45 DAS, T14 was on par with T6, T8, T10 and T12. At 60 DAS, T14 was on par with T4, T6, T8, T9, T10, T11, T12 and T13. Electron transport rate (ETR) were observed maximum in T6 and T14 which were on par with T8, T10 and T12 at 25 DAS. At 45 DAS, T14 was on par with T6, T8, T10 and T12. At 60 DAS, T14 was on par with T2, T4, T6, T8, T10, T11, T12, and T13. A perusal of biochemical data showed that T6 and T14 had maximum leaf chlorophyll content at 25 DAS. At 45 DAS, T6 had the highest chlorophyll content which was on par with T8, T12 and T14. At 60 DAS, maximum chlorophyll content was recorded in T6 which was on par with T14. Maximum proline content was recorded in T1 at 25, 45 and 60 DAS. Regarding yield parameters average number of pods per plant and average number of seeds per plant were recorded maximum in T6 and T14, Seed yield was found to be increased by 43 per cent in T6 when salicylic acid @ 100 ppm seed priming and foliar application were given and 42.11 per cent increase in seed yield was noticed in T14 when seed priming was given with brassinolide @ 0.3 ppm and foliar spray at 0.5 ppm. Among only foliar spray of growth regulators without considering seed priming, brassinolide @ 0.5 ppm (33.74 per cent) and salicylic acid @ 100 ppm (33.29 per cent) were recorded maximum increase in seed yield. Foliar spray of thiourea was increased the yield by 26.32 per cent over control. Maximum net returns were obtained from treatment of seed priming and foliar spray with salicylic acid 100 ppm (T6) followed by T8 and T5. Even though, the gross returns were maximum from brassinolide treated plants, the net return was less due to higher cost of brassinolide. The highest BC ratio was from salicylic acid treated plants T6 (2.86) followed by T8 (2.73) and T4 (2.67). Among foliar sprayed treatments T5 recorded maximum BC ratio (2.66) and thiourea treatment recorded BC ratio 2.52. Results of the study revealed that seed priming and foliar spray of salicylic acid 100 ppm was significantly superior to all other treatments with respect to yield and net return. It can be concluded that among the treatments seed priming and foliar application of salicylic acid 100 ppm and seed priming with brassinolide @ 0.3 ppm and 0.5 ppm foliar spray showed the best results. Among foliar spray without seed priming salicylic acid 100 ppm and brassinolide 0.5 ppm superior in all parameters. Maximum economic returns were recorded from salicylic acid treated plants, even though highest seed yield and gross returns observed from brassinolide treatment because of high cost of chemical, net returns were minimised. Therefore, seed priming and foliar application of salicylic acid (100 ppm) significantly enhanced seed yield and net returns in cowpea.
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    Physiological aspects of ex vitro establishment of tissue cultured orchid plantlets
    (Department Of Plant physiology, College Of Agriculture, Vellayani, 2000) Samasya, K S; Viji, M M
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    Physiological, anatomical and molecular analysis of coconut palms (Cocos nucifera L.) affected with yellowing.
    (Department of Plant Physiology,College of Agriculture, Vellayani, 2011) Deepa, S; Manju, R V
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    Effect of abiotic stress factors on growth and secondary plant metabolism in Withania somnifera (L) Dunal
    (Department of Plant Physiology, College of Agriculture, Vellayani, 2006) Lini Jacob; Manju, R V
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    Physiology and secondary metabolite production in genetically transformed brahmi (Bacopa monnieri L. wettst.) with cytokinin synthesizing isopentenyl transferase (ipt) gene
    (Department of Plant Physiology, College of Agriculture, Vellayani, 2007) Vighnesha; Roy Stephen
    An experiment was conducted in the Department of Plant Physiology, College of Agriculture, Vellayani, to overexpress cytokinin synthesizing ipt gene in Bacopa monnieri through Agrobacterium tumefaciens mediated transformation and to regenerate the transformed plants through tissue culture for analyzing the influence of overexpression of ipt gene on growth, physiology and secondary metabolite production. The transformation and molecular works were done in Rajiv Gandhi Center for Biotechnology, Trivandrum. Escherichia coli strain JM 109 was transformed independently with pBI B33 ipt and pBI SAG12 ipt. Triparental mating was done using Agrobacterium tumefaciens strain EHA 105, pRK 2013 and recombinant E.coli. Plasmids were isolated from recombinant E.coli and recombinant Agrobacterium cells to confirm the successful transformation of constructs. Both have showed the insertion release when double digested with restriction enzymes EcoRI and HindIII. Pre incubated leaf explants of Bacopa monnieri were co-cultivated with the recombinant Agrobacterium for two days and transferred to regeneration medium containing MS supplemented with 2mgl-1 BA, 15mgl-1 kanamycin and 300mgl-1 cefotaxime. Putative transformants were regenerated from co-cultivated explants when placed on the selection medium containing 15mg/l kanamycin and 300mg/l cefotaxime. Uninfected explants failed to regenerate in presence of kanamycin. Rooting was not found in the MS medium devoid of growth regulators. Sub culturing of shootlets was done in MS medium supplemented with 1ppm GA and 1ppm IAA. Hardening was done to the fully rooted plants and were kept in five replications for further analysis. DNA was isolated from both wild type and transformants. PCR amplification for nptII and ipt gene specific primers showed presence of gene in transformants but not in the wild type. From the selected transformants, RNA was isolated and RT-PCR was done. RT-PCR analysis confirmed the expression of ipt and nptII gene in all the transformants, while there was no expression in the wild type. Expression of constitutively expressed plant gene –actin was used as loading control. Southern hybridization of PCR amplified products gave the evidence for the presence of ipt gene only in transformants but not in wild type. Physiological and biometric observations were performed on both transformants and wild type which served as control over the transformants. Plant height was more in transformants compared to the wild. Both root length and relative water content was more in wild compared to the transformants. Other parameters like number of branches and number of leaves were higher in the transformants than in the wild. Total chlorophyll, chlorophyll a and chlorophyll b were found to increase for first five weeks in all treatments, after that there was a decrease in the total chlorophyll, chlorophyll a and b in wild type but transformants were able to retain higher contents throughout the period of study. Total soluble protein content was higher in the transformants than the wild type. Stomatal frequency showed a significant difference between the treatments. Higher number of stomata was observed in the transgenics compared to the wild type. The distribution of stomata also differed significantly. In wild type the distribution was equal in both upper and lower surface of leaf but in transformants a higher number of stomata were observed at the lower surface than the upper surface. Cytokinin content was estimated using ELISA. There was a significant variation in cytokinin, iPA concentration between wild type and transformants. Transformants had higher cytokinin content than the wild type. The transformant with B33 promoter had more cytokinin content than transformant with SAG promoter. Bacoside, the major secondary metabolite of the plant was estimated by HPLC and its content between the wild type and transformants were found to be on par. In this experiment, the overexpression of ipt gene in bacopa resulted a higher amount of cytokinin in transgenics and hence had higher growth rate, protein and pigment content. Overexpression of ipt may not increase the bacoside content in the bacopa.
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    Effect of abiotic stress on the physiology and andrographolide content in andrographis paniculata nees.
    (Department of Plant Physiology, College of Agriculture, Vellayani, 2004) Parthasarathy, V; Roy Stephen
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    Provenance evaluation in the seedling characters of neem (Azadirachta Indica A. Juss)
    (Department of tree physiology and breeding, College of Forestry, Vellanikkara., 1997) Vinod, S; Vijayakumar, N K
    A study was conducted at College of Forestry, Vellanikkara, Trichur on provenance evaluation in the seedling characters of neem (Azadirachta indica A. Juss) for a period of one year from 1995 to 1996. The experiment was laid out in a completely randomised design. A total of eight provenances were used in this study they are Dindigul, Nagarcoil, Coimbatore, Trichur, Srivelliputhur, Palghat, Ghatti Subramanya and Molakalmur. In respect of various seed characters studied Nagarcoil was the best performer in characters like 100 seed weight, seed breadth and germination percentage. Trichur was the best performer in seed length and seed length breadth ratio and Srivelliputhur was the best performer in thickness of pericarp. In terms of various seedling characters studied Coimbatore was the best performer in height, leaf number, leaf area, stem dry weight, leaf dry weight, and shoot dry weight. Palghat provenance was superior with respect to root dry weight, and root shoot ratio; Nagarcoil was the best in terms of collar girth and Dindigul in total dry weight. Nevertheless, Coimbatore provenance was found to be the best performer in most of the seedling character studied. Isozyme banding pattern for peroxidase showed two bands PRX-1 and PRX-3 in common. Eight provenances were grouped in to two based on the presence or absence of PRX-2. No significant variation was observed in terms of chlorophyll - A, Band total chlorophyll content between provenances. Number of stomata per square centimetre was maximum in Coimbatore provenance. For the genetic characters studied 100 seed weight and germination percentage recorded maximum GCV and PCV for seed characters and shoot weight and shoot root ratio for seedling characters. Maximum heritability and genetic gain were recorded in germination percentage and height and collar girth in seedling characters. Application of Mahalanobis' D2 statistics and Tocher's method of clustering resolved eight provenances in to four distinct clusters. Cluster I comprising of three provenances (Dindigul, Palakkadu and Ghatti Subramanya). Cluster II comprising of only one cluster (Coimbatore), cluster III comprising of again only one cluster (Molakalmur) and cluster IV comprising of three provenances (Nagarcoil, Trichur and Srivelliputhur). Incidence of pests was not noticed during the entire period of investigation. All provenances were found affected by sooty mold caused by Capnodium sp. during the rainy seasons with out affecting the growth of the seedlings.