Development and Abortion of Flowers in Capsicum annuum Exposed to High Temperatures

Abstract

<jats:p>Reduction of floral number in <jats:italic>Capsicum annuum</jats:italic> has been observed during growth at high temperature. To determine whether decreased flower production or increased flower abscission is a direct response to high temperatures or a response to water stress induced by high temperatures, we compared flowers and fruit produced and flowers aborted to leaf growth rate, osmotic potential, stomatal conductance, and chlorophyll fluorescence of two cultivars. To determine the stage(s) of floral development that are most sensitive to high temperatures, flower buds were wax-embedded and examined at each stage of development during heat treatment. Rate of floral development also was examined. At first visible floral bud initiation, plants were transferred to each of three controlled environment growth chambers with set temperatures and vapor pressure deficits (VPD) of 25°C, 1.1 kPa; 33°C, 1.1 kPa; and 33°C, 2.1 kPa. Flower bud production and leaf growth rate were not significantly affected by high temperatures. Pepper fruit set, however, was inhibited at 33°C at either VPD. Preliminary water relations data suggested that water potentials were more negative under high temperature conditions. Differences in leaf fluorescence were statistically significant for temperature treatments, but not for VPD. Temperature is the primary factor in the decrease of fruit production in pepper. Decreased production is due to flower abortion and not to decreased flower initiation or plant growth.</jats:p>

Yield and storability of green fruits from hot pepper cultivars (Capsicum spp.)

“…They reported that, as the mean daily temperature increase the number of fruits per plant also increased. Erickson and Markhart (1997) noted that, temperature is the primarily factor in the decrease of fruit production as reduced fruit set was due to flower abortion and not due to decreased flower Awole et al 12665 initiation or plant growth. Cocharn (1964) showed that, the poor fruit set at high temperature to be due to excessive transpiration by the plant which could partly be the cause for the differences observed in this study.…”