From the floret to the canopy: High temperature tolerance during flowering

Area of Science:

• Agricultural Science
• Plant Physiology
• Climate Change Biology

Background:

• Climate warming is increasing the frequency and intensity of heat waves globally.
• Heat waves often coincide with critical crop developmental stages, particularly flowering, threatening global food security.
• Understanding high temperature (HT) sensitivity in crop reproductive organs is crucial for improving seed set and crop resilience.

Purpose of the Study:

• To systematically review and integrate knowledge on HT sensitivity of reproductive organs in rice, wheat, and maize.
• To define critical HT thresholds for seed set in these three staple crops.
• To assess crop-specific responses and protective mechanisms against HT stress during flowering.

Main Methods:

• Literature review synthesizing existing research on HT effects on crop reproduction.
• Analysis of HT impacts on flowering dynamics, floret development, pollination, and fertilization.
• Identification of critical temperature thresholds for seed set in rice, wheat, and maize.

Main Results:

• Defined critical HT thresholds: rice (37.2°C), wheat (27.3°C), and maize (37.9°C).
• Identified varied HT impacts: catastrophic in maize (spikelet closure, pollen tube arrest), beneficial in rice (cleistogamy, bottom anther dehiscence), and advantageous in wheat (cleistogamy, secondary opening).
• Highlighted crop self-protection mechanisms: lower canopy temperatures in rice and husk leaf insulation in maize.

Conclusions:

• Rice, wheat, and maize exhibit distinct reproductive responses and protective strategies to HT stress.
• Findings inform crop modeling, management, and breeding for enhanced resilience to climate change.
• Targeted strategies are needed to mitigate HT impacts on global food production.