Iron sources in relation to leaf senescence in french bean (phaseolus vUlgarisl.)

Abstract

Pot and field experiment were conducted to study the effects of three iron sources, viz., Fe-EDTA, Fe-EDDHA and FeSO4 on the yield of french bean (Phaseolus vulgaris L.). The natural available iron in the soil was 2–4 ppm. All the iron sources in general, induced a significant increase in chlorophyll ‘a and b’, and indole-3-acetic acid components of french bean when used at a concentration of 5 to 10 mg kg−1 soil. Remarkably, these favourable acquisitions were more prominent in the cases of Fe-EDDHA (@ 5 mg kg−1 soil) and Fe-EDTA (@ 5 mg kg−1 soil) treatments, while a double dose of FeSO4 (@ 10 mg kg−1 soil) was required to induce a parallel change in the characteristics noted above. A critical individual assessment of the effects of the first two iron sources obviate the fact that Fe-EDDHA is superior most in inducing a delayed senescence and the related characteristics of applied importance. These effects were significantly better over those induced by the corresponding concentrations of Fe-EDTA, possibly due to known higher stability constant of Fe-EDDHA as well as its better mobility in plants. While in the control (iron-untreated) plants chlorophyll destruction (quite simultaneously a decline in the IAA content) is more rapid at the post-flowering stage, leading to an early senescence, reduced photosynthetic duration and low yield, the iron-treated plants exhibited a delayed senescence exhibited a delayed senescence of leaves coupled with a significantly enhanced photosynthetic duration and yield. Apparently, therefore, soil iron enrichment is of considerable importance in the regulation of physiological factors leading to an increase in the yield of french bean plants. © 1988, Taylor & Francis Group, LLC. All rights reserved.