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Subject: Plant Physiology × Author: Sah, Chitra × End date: 2004 × Start date: 2004 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Biogenesis of chloroplast and photosynthetic efficiency in mango (Mangifera indica L.) leaves
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2004-08) Sah, Chitra; Singh, M.
    Mango (Magnifera indica L.) is an important fruit crop of India. The fruit yield depends upon flowering and proper fruit set, which is largely influenced by the environmental variables. Vegetative growth in mango is periodic with major number of flushes occurring in the months of April-June when temperature is high coupled with strong irradiance and low humidity. The proposed study was undertaken to correlate the effect of environmental variables with biogenesis of chloroplast and acquisition of photosynthetic ability in expanding immature leaves. These leaf flushes were analysed morphologically, anatomically and bio-chemically. The growth stages classified as S1, S2 and S3 were studied for plastid/chloroplast development through transmission electron microscopy. The chlorophyll fluorescence variable yield (Fv/Fmax) was monitored to study the acquisition of photosynthetic efficiency. Immature and mature leaves differentially acquired photosynthetic ability. The young leaves were found susceptible towards mid-day depression of their Fv/Fmax compared to the mature leaves. The mature leaves were less affected under high temperature. Investigations related to PS II performance showed ca. 50 % less photosynthetic efficiency in young leaves as compared to the mature leaves. Thus, our findings suggest that acquisition of photosynthetic machinery in the form chloroplast biogenesis seems to be coupled with photosynthetic efficiency of the leaves.