GROWTH, ANATOMY AND CHLOROPHYLL FLUORESCENCE OF CORIANDER PLANTS (CORIANDRUM SATIVUM L.) TREATED WITH PROHEXADIONE-CALCIUM AND DAMINOZIDE

摘要

This study evaluates the effects Of the two gibberellin inhibitors (daminozide, prohexactione-calcium) oil certain growth and anatomical characteristics of coriander (Coriandrum sativum L.). Both growth retardants were found effective in reducing stem elongation: that response varied with the concentration used. Prohexadione-Ca at 200 mg l(-1) reduced height by 38%. Coriander fruits were heavier after the application of proliexadione-Ca, but this did not translate to increased fruit yield or fruit essential oil yield. Prohexdione-Ca induced precocious anthesis (3-5 days earlier). Both prohexadione-Ca and daminozide apparently affected leaf and stern anatomy. Generally, retardant-treated plants possessed thicker leaves, wider stems with more collenchyma tissue, and more vessels in the vascular bundles. Chlorophyll fluorescence measurements disclosed a decrease in the photochemical efficiency of PSII in retardant-treated plants as compared to the controls. The chlorophyll fluorescence parameters F-v/F-m and F-v/F-o can provide a tool for early diagnosis of life use of growth retardant even before any signs of growth retardation are visible in the plants.