High Night Temperatures During the Floral Bud Stage Increase the Abscission of Reproductive Structures in Cotton

Abstract

Cotton‐producing regions throughout the world often experience high night temperatures (HNTs), affecting flowering and yield in cotton (Gossypium hirsutum). The objective of this study was to quantify the effects of high nighttime temperatures on the physiological and biochemical characteristics of cotton during the floral bud and flowering stages. Growth chamber experiments were conducted in 2011–2012 and treatments included a control (day/night temperature of 32/24 °C) and two HNT treatments (32/29 °C from 8:00 pm to 12:00 am) for 3 weeks from the beginning of each phenological stage, i.e., first floral bud (B1) and first flower (F1). The results indicated that increased night temperatures (NTs) during the floral bud and flowering stages increased the rate of flower production per plant. However, no increase was observed in the final number of reproductive structures because the rate of floral abortion also increased for both treatments compared to the control. Additionally, the increase in night temperature during the floral bud stage reduced the sucrose content in the flower, resulting in decreased pollen viability and premature abortion of reproductive structures while the onset of flowering period was also delayed and lower accumulation of reproductive dry matter was observed. HNTs during the flowering stage reduced the number of seeds per locule and the number of seeds per boll. In general, higher than optimum NTs affected sucrose metabolism of the cotton flower and consequently its pollen viability. As a result the flowering period was delayed and a reduction in reproductive dry matter accumulation was observed due to premature abortion of reproductive structures. Finally, cotton is more sensitive to HNT at floral bud stage and this finding may be important to adjust cotton planting date, management and breeding.

Pollen, ovules, and pollination in pea: Success, failure, and resilience in heat

“…Heat stress appeared to accelerate the growth of pea ovules in both cultivars tested following heat exposure for 4 days, because ovule size of heat‐exposed plants was greater compared with ovules from control plants. Although we are not aware of any previous reports in pea demonstrating acceleration of ovule growth shortly after fertilization in response to heat stress, high night temperature during flowering increased the rate of flower production per plant in cotton (Echer et al, ). Similarly, a shorter life cycle caused by faster development has been observed in nonperennial crops under heat stress (Bruckner & Frohberg, ; Hatfield & Prueger, ).…”

Genetic mechanisms of abiotic stress tolerance that translate to crop yield stability

“…This includes the production and fertility of male gametes, pollen-pistil interactions and female fertility 5 . Following fertilization, high night temperatures reduce seed maturation, thereby affecting seed quality in many crops such as rice 5,124,125 . Important acclimation mechanisms that maintain the key functions of respiration and photosynthesis include rapid alterations in gene expression, increases in heat shock protein (HSP) levels, modification of membranes, alterations in the cytoskeleton and management of oxidative stress.…”

Reproductive development response to high daytime temperature in field pea

“…Similarly, an increase in abortion frequency of pea floral buds and flowers due to heat stress has been documented (Guilioni et al., ). High night temperatures during flowering increased the rate of flower production per plant in cotton, whereas no increase was seen in the final number of reproductive organs because abortion of flowers was high compared to the control regime (Echer, Oosterhuis, Loka, & Rosolem, ). However, we did not observe an increase in flower abortion when pea plants were exposed to high temperature when flowers were already fully open at Node 2.…”