In: Phyton 55, Fasc. 2 (2015): S. 251-270 DOI: 10.12905/0380.phyton55(2)2015-0251

Photosynthetic Responses of Field Bean toBotrytis fabae and Phenolics

Key words: Chloroplast ultrastructure, chocolate spot disease, fungicides, salicylic acid, shikimic acid, Botrytis fabae, Vicia faba.

Aldesuquy H. S. 2015. Photosynthetic responses of field bean to Botrytis fabae and phenolics. – Phyton (Horn, Austria) 55 (2): 251–270, with 11 figures.

Summary
This study investigated the effect of shikimic and salicylic acids at the concen­trations of 0.4 and 0.7 mM, respectively, or their combination as phenolic com­pounds and Ridomil MZ at the concentration of 250g/100 L as a fungicide on leaf area, pigment content, photosynthetic activity, chloroplasts number and chloroplast ultrastructure of Vicia faba leaves infected by Botrytis fabae. Adverse changes in the previous parameters (15 days after the inoculation) were observed. The infection of Vicia faba by B. fabae caused a massive depletion in leaf area, pigment content, Hill reaction, soluble and insoluble photosynthates as well as chloroplasts number while application of phenolic compounds caused an obvious increase in these pa­rameters. The ultra-structural change of chloroplasts was obvious on the disorgani­zation of membrane system, thickening of envelope and absence of starch grains. When the healthy plants were treated with shikimic acid alone, mesophyll cells showed normal (i.e. the usual or standard or typical) chloroplasts with many starch grains; meanwhile the same plants showed mesophyll cells packed with chloro­plasts when treated with salicylic acid alone. Treated healthy plants with shikimic and salicylic acids together showed many divided chloroplasts. When infected plants were treated with shikimic acid, salicylic acid or both together, unaffected normal chloroplasts were detected. The dose of fungicide used in this investigation appeared to be safe on the chloroplasts except slight changes. The recovery of chlo­roplasts in infected host by using these chemical inducers may encourage the use of them as protective control means. The results of the present study showed also that the application of chemical inducers such as shikimic and salicylic acids or their interaction increased the resistance of Vicia faba against the chocolate spot disease caused by Botrytis fabae.