Flower developmental stage and organ sensitivity of bell pepper (Capsicum annuum L.) to elevated temperature

Abstract

High temperatures adversely affect crop productivity of several plant species including bell pepper ( Capsicum annuum L. var. annuum ). The objectives of this study were: (1) to determine whether flower ontogeny is adversely affected by high temperature during different phases of development, including pre-and post-pollination events; (2) to determine the duration of high temperature exposure necessary to cause reduction in fruit set; and (3) to determine whether injury to the pistil or stamen during development is responsible for reduced fruit set during high temperature. We determined that flower buds at <2·5 mm in length, corresponding to microspore mother cell meiosis to tetrad dissolution, and flowers that reached anthesis during the high temperature exposure had reduced fruit set when exposed to 33 °°°° C for 48 or 120 h. Flower buds at <2·5 mm in length also had reduced pollen viability when exposed to 33 °°°° C for 120 h. Morphological examination demonstrated that meiocytes initiated tetrad formation, but after dissolution the microspores remained small and clumped without a thick exine. High temperature exposure at a latedevelopment, pre-anthesis stage did not affect pistil or stamen viability, but high post-pollination temperatures inhibited fruit set, suggesting that fertilization is sensitive to high temperature stress.

Effect of two environments and fertilization recommendations on the development and production of bell pepper (cv. Nathalie)

“…Similarly, fruit reduction by high temperatures has been associated with the reduction in the concentrations of reducing sugars in flower buds, flowering and to an increase on ethylene production (Erickson & Markhart, 2002).…”

“…In order to observe the temperature effect, Erickson & Markhart (2002), evaluated two cultivars, under greenhouse conditions and under a temperature of 33 °C with three intensities (6, 48 and 120 hours, respectively) in different flowering stages. As a result, when flowering in their early stages were exposed for 48 and 120 hours, a reduction in yields was found; this stage corresponded to microspore mother cell meiosis, which, when not completed, resulted in unfertilized flowers.…”

Survival Analysis of Flower and Fruit Abortion in Sweet Pepper

“…The temperature was increasing slightly during the season, but did not reach extreme high or extreme low values (average daily temperatures ranged from 19.1 to 27.0°C). However, it is known that low temperatures (Pressman et al, 1998) as well as high temperatures (Erickson and Markhart, 2002) increase abortion, due to malformation of pollen and consequently reduced pollination and fruit set. To get a good quantification of the effect of temperature on abortion, an experiment in which plants are grown at different temperatures should be conducted.…”

Identification of metabolites involved in heat stress response in different tomato genotypes

“…Pollen germination was altered in tomato under heat stress (Sato et al 2000) and led to a delay in fruit development and parthenocarpy (Sato et al 2001, Abdelmageed andGruda 2009). Plants that can be potentially parthenocarpic become visible when no viable pollen are present; this has been observed in tomato, bell pepper (Aloni et al 2001, Erickson andMarkhart 2002) and in rapeseed (Young et al 2004). …”

“…In peanuts, the most sensitive stages were during the development of microspores (four days before anthesis) and at anthesis (Prasad et al 2001). In bell pepper, heat stress at microspore mother cell meiosis led to reduction of pollen viability, fruit set and seed number, whereas heat stress at later developmental stages did not affect the pollen viability (Erickson and Markhart 2002). The developmental sensitivity to heat stress in pollen seems to be species-specific, with meiosis a common sensitive stage, for most crops.…”