Influence of ethephon on net assimilation rate, relative growth rate and leaf area index of sugarloaf pineapple (Ananas comosus (L.) Merr.)

Abstract

A field experiment was conducted to study the effects of ethephon on net assimilation rate (NAR), relative growth rate (RGR) and leaf area index (LAI) of pineapple cv. Sugarloaf. The results demonstrated that ethephon decreased RGR, NAR and LAI and that the decrease was proportional to the concentration of the growth regulator. The reduced RGR and LAI are attributed to the decrease in leaf number and size, and consequently total leaf area, by ethephon. Reduced total leaf area, increased mutual shading of leaves and a probable adverse effect of the growth regulator on the photosynthetic mechanism are used to explain the reduction of NAR.