Abstract:

To investigate the regulatory effects of environmental temperature and humidity on Amomum villosum pollen germination and pollen tube growth. Aniline blue staining combined with fluorescence microscopy was employed to systematically observe pollen germination and pollen tube growth dynamics on pistils of Amomum villosum florets under varying temperature and humidity conditions. Results indicated that pollen could germinate within a temperature range of 15-40℃ and humidity conditions of 40%-100%. Under conditions of 25-30℃, pollen completed germination within 2 hours. Pollen tube growth exhibited extreme sensitivity to environmental changes. At 15℃ low temperature and under varying humidity (40%-100%), pollen tube growth was completely inhibited. At 20℃, pollen tube growth was influenced by humidity changes. Optimal pollen tube growth occurred at 25℃ and 30℃ under varying humidity (40%-100%) conditions. Pollen tubes extend to the base of the style within 8-12 hours post-pollination and enter the ovary within 12-24 hours. At 35℃, pollen tube growth rate decreased with increasing humidity. At 40°C under varying humidity levels (40%-100%), pollen tube growth was nearly completely inhibited. Short-term low-temperature (15℃) or high-temperature (40℃) stress also inhibited pollen tube growth, particularly under high-temperature (40℃) and high-humidity (≥80%) conditions, which completely suppress pollen tube development. Amomum villosum pollen exhibited strong environmental tolerance during germination, but pollen tube growth was sensitive to temperature and humidity fluctuations. Extreme temperatures (especially high temperatures and high humidity) should be avoided. These findings provide theoretical support for optimizing Amomum villosum cultivation management techniques, including quantitative temperature and humidity management in the field, high-temperature and high-humidity early warning systems, and the breeding of new pollen tube stress-resistant varieties.

Key words: Amomum villosum, pollen germination, pollen tube elongation, optimal temperature and humidity, temperature and humidity stress