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1. Differential responses of iron, magnesium, and zinc deficiency on pigment composition, nutrient content, and photosynthetic activity in tropical fruit crops

Creator:
Balakrishnan, K., Rajendran, C., and Kulandaivelu, G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Achras, chlorophyll fluorescence, Citrus, Eugenia, Jamun, Mangifera, mango, nutrient deficiency, sapota, and sweet orange
Language:
Multiple languages
Description:
Fe, Mn, and Zn affected the chlorophyll (Chl) content whereas Fe deficiency caused larger reduction of total chlorophyll content than Mg and Zn deficiencies. Mg deficient mango had a higher Chl a/b ratio than the respective healthy plants. The foliar contents of Fe, Zn, and Mg in the deficient leaves were lower than the critical level. Nutrient deficiency significantly affected the Fv/Fm ratios as observed from the Chl fluorescence induction curves. Fe deficiency resulted in larger reduction of variable fluorescence than Mg and Zn deficiency. and K, Balakrishnan, C. Rajendran, G. Kulandaivelu.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Species specific diurnal changes in chlorophyll fluorescence in tropical deciduous and evergreen plants growing in the field during summer

Creator:
Joshi, S.C.
Format:
print
Type:
model:internalpart and TEXT
Subject:
Acer, Aesculus, Bauhinia, Boehmeria, Celtis, Dalbergia, Eugenia, Ficus, Grewia, and Sapium
Language:
Multiple languages
Description:
Diumal changes in chlorophyll (Chl) a fluorescence characteristics of sun-exposed and shade leaves of some tropical and temperate tree species growing under fíeld conditions on sunny and cloudy days during summer were recorded. Significant reduction in photochemical efficiency of photosystem (PS) 2 measured as ratio during periods of maximum irradiance was observed in sun-exposed leaves of some plants. The extent of this reduction was probably a function of the plant species. Among the tropical species tested, Boehmeria rugulosa, Celíis ausíralis, Dalbergia sissoo, Eugenia jambolana and Grewia optiva showed maximum reduction (15-22 %), whereas species like Ficus racemosa and Sapium sebiferum showed least dechne (< 7 %) in the F^/F^ ratio. On the other hand, no significant reduction in this ratio was observed in Bauhinia purpurea. Temperate species, v/z. Acer oblongum and Aesculus indica, were most susceptible to high irradiances. Prolonged exposure of these plants to high irradiances resulted in lesion development in their leaves characterized by reduction in pigment contents and Fy/F^, ratio. Plant species with considerable midday dechne in Fy/Fn, ratio showed (7) slight but significant rise in initial fluorescence (Fq), (2) pronounced decrease in F^ value, and (3) significant reduction in area over the curve between Fq and Fj„ indicating the pool size of electron acceptors on the reducing side of PS2. The depression in Fy/F^ ratio though reversible could not be alleviated even after watering the plants at hourly intervals. No reduction in Fy/F^, was observed in shade leaves of the same plants and/or when measurements were taken on cloudy days. Hence high solar radiation and high atmospheric evaporative demand existing during summer period could probably be the major contributoiy factors for this reduction.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public