Effect of Prior Heat Stress on the Early Growth of Carica papaya

Abstract

The experiment was carried out to determine the effects of heat stress on some growth parameters like shoot height, leaf area, fresh weight, dry weight as well as the accumulation of chlorophylls in Carica papaya. Seedlings of C. papaya were exposed to prior heat stress at 40 °C. A group of plants was placed in a Gallenkamp oven for four hours; another group of plants was placed in the oven for eight hours while the third group of plants was placed in a dark cupboard for the period of eight hours. Sampling was carried out at weekly intervals starting from seven days after treatment. Plants were randomly picked from each of the three treatments. Three replicates were used for each parameter. The results obtained from the study showed that there was an increment in the shoot height, leaf area, fresh weight and dry weight from the beginning to the end of the experimental period. However, the accumulation of chlorophylls did not follow a particular pattern. The analysis of variance carried out on the data obtained showed that heat stress had a significant effect on the petiole length, shoot height, leaf length, leaf width, leaf area, fresh weight and dry weight. Heat stress, however, did not produce a significant effect on the accumulation of chlorophylls a and b and total chlorophyll.