Saira Banu V K
Anatomical and Biochemical Bases of Resistanance in Banana to Yellow Sigatoka Leaf Spot Disease - Vellanikkara Department of Plant Pathology, College of Horticulture 2001
Banana is an important fruit crop of Kerala, which is commonly
infected by yellow sigatoka leaf spot disease caused by Mycosphaerella musicola
Leach.
Investigations on anatomical and biochemical bases of resistance in .
banana to yellow sigatoka leaf spot disease were carried out in the Dept of Plant
Pathology and Biochemistry Laboratory of the College of Horticulture,
Vellanikkara during 2000-2001.
Severity of sigatoka disease was observed maximum 10 the peak
monsoon month of July (cool moist period) followed by October (warm moist
period) and April (warm dry period) and minimum in January (cool dry period).
Maximum growth of M musicola was obtained in the medium potato
glucose yeast extract agar (PGYEA) and poor sporulation in the medium banana
dextrose agar (BnDA). Red pigmentation was observed in all media tried.
The study revealed that the four different groups of banana differed
significantly in the various anatomical and biochemical parameters.
The resistant variety, Manoranjitham (AAA) was characterised by
thickest cuticle and epidermis with inter mediate sized epidermal cells on the
adaxial surface and denser pattern of epicuticular wax deposition on the abaxial
surface of leaves. Thinner spongy and palisade tissues, maximum number of large
and closely placed vascular bundles, thickest lower epidermis and decrease 10
number of stomata/unit area on the adaxial and abaxial surfaces of leaves.
The highly susceptible variety, Grand Naine (AAA) showed thinner
cuticle, thickened and large sized epidermal cells on the adaxial surface and faint
pattern of epicuticular wax deposition on the abaxial surface of leaves. Less
number of small and distantly placed vascular bundles, thicker spongy and palisade
tissues and maximum number of stomata lunit area on the adaxial and abaxial
surfaces of leaves.
After pathogen infection the resistant variety Manoranjitham (AAA)
showed partial disintegration of spongy mesophyll tissues and the highly
susceptible variety Grand Naine (AAA) showed complete disintegration of
chloroplast and mesophyll with necrotic vascular bundles.
Stomata was found opened during day time and closed during night
hours in both healthy and diseased leaves.
In the biochemical parameters studied, the resistant variety,
Manoranjitham (AAA) possessed higher quantities of total phenol, OD phenol, non
reducing and total sugars, protein and peroxidase activity and intermediate values
for proline and activity of polyphenol oxidase and lower quantity of reducing
sugar.
The highly susceptible variety, Grand Naine (AAA) was characterised
by higher quantities of reducing sugar and intermediate values for total phenol, non
reducing and total sugars and lower quantity of proline, protein, OD phenol and
peroxidase and polyphenol oxidase enzyme activities.
After pathogen infection, higher quantity of OD phenol, reducing sugar
and activity of polyphenol oxidase enzyme was observed in the variety
Manoranjitham (AAA) where the content of total phenol, non reducing and total
sugars, proline, protein and activity of peroxidase enzyme decreased. The highly
susceptible variety, Grand Naine (AAA) exhibited higher quantities of total
phenol, reducing sugar, proline and higher activities of peroxidase and polyphenol
oxidase enzymes and lower quantities of OD phenol, non reducing and total sugars
and protein.
The concentrated culture extracts of M musicola In seven different
media gave different Rf values.
632.3 / SAI/AN
Anatomical and Biochemical Bases of Resistanance in Banana to Yellow Sigatoka Leaf Spot Disease - Vellanikkara Department of Plant Pathology, College of Horticulture 2001
Banana is an important fruit crop of Kerala, which is commonly
infected by yellow sigatoka leaf spot disease caused by Mycosphaerella musicola
Leach.
Investigations on anatomical and biochemical bases of resistance in .
banana to yellow sigatoka leaf spot disease were carried out in the Dept of Plant
Pathology and Biochemistry Laboratory of the College of Horticulture,
Vellanikkara during 2000-2001.
Severity of sigatoka disease was observed maximum 10 the peak
monsoon month of July (cool moist period) followed by October (warm moist
period) and April (warm dry period) and minimum in January (cool dry period).
Maximum growth of M musicola was obtained in the medium potato
glucose yeast extract agar (PGYEA) and poor sporulation in the medium banana
dextrose agar (BnDA). Red pigmentation was observed in all media tried.
The study revealed that the four different groups of banana differed
significantly in the various anatomical and biochemical parameters.
The resistant variety, Manoranjitham (AAA) was characterised by
thickest cuticle and epidermis with inter mediate sized epidermal cells on the
adaxial surface and denser pattern of epicuticular wax deposition on the abaxial
surface of leaves. Thinner spongy and palisade tissues, maximum number of large
and closely placed vascular bundles, thickest lower epidermis and decrease 10
number of stomata/unit area on the adaxial and abaxial surfaces of leaves.
The highly susceptible variety, Grand Naine (AAA) showed thinner
cuticle, thickened and large sized epidermal cells on the adaxial surface and faint
pattern of epicuticular wax deposition on the abaxial surface of leaves. Less
number of small and distantly placed vascular bundles, thicker spongy and palisade
tissues and maximum number of stomata lunit area on the adaxial and abaxial
surfaces of leaves.
After pathogen infection the resistant variety Manoranjitham (AAA)
showed partial disintegration of spongy mesophyll tissues and the highly
susceptible variety Grand Naine (AAA) showed complete disintegration of
chloroplast and mesophyll with necrotic vascular bundles.
Stomata was found opened during day time and closed during night
hours in both healthy and diseased leaves.
In the biochemical parameters studied, the resistant variety,
Manoranjitham (AAA) possessed higher quantities of total phenol, OD phenol, non
reducing and total sugars, protein and peroxidase activity and intermediate values
for proline and activity of polyphenol oxidase and lower quantity of reducing
sugar.
The highly susceptible variety, Grand Naine (AAA) was characterised
by higher quantities of reducing sugar and intermediate values for total phenol, non
reducing and total sugars and lower quantity of proline, protein, OD phenol and
peroxidase and polyphenol oxidase enzyme activities.
After pathogen infection, higher quantity of OD phenol, reducing sugar
and activity of polyphenol oxidase enzyme was observed in the variety
Manoranjitham (AAA) where the content of total phenol, non reducing and total
sugars, proline, protein and activity of peroxidase enzyme decreased. The highly
susceptible variety, Grand Naine (AAA) exhibited higher quantities of total
phenol, reducing sugar, proline and higher activities of peroxidase and polyphenol
oxidase enzymes and lower quantities of OD phenol, non reducing and total sugars
and protein.
The concentrated culture extracts of M musicola In seven different
media gave different Rf values.
632.3 / SAI/AN