The increased surface air temperature is a critical observed climatic variations continuing to cause severe disruption to agriculture, vegetation, and even economies and societies throughout the world. In China, the country-averaged annual mean surface air temperature has increased by 1.1°C over the past 50 years, which could have had profound implications for the plant phenology, distribution of plant species, and crop yield etc.. Enhancement of accumulated temperature play a predominantly role on various vegetation processes (e.g., nutrient content and allocation), when focusing on the ontogenetic process of a plant, thereinto fertility is one of the most sensitive trait. Chinese cabbage lines supplied in the experiments would change their fertility significantly due to the change of temperature. So the paper was a case study on "how" the male sterility operate with temperature, and whether there is a female sterility and is it an explanation to "why" the systems behave as poor seed set and "what" technique might improve it.
Results/Conclusions
The experiments given under two conditions of natural and controlled temperature revealed that higher temperature above 24°C caused severe disruption to male fertility and altered floral morphology of smaller corolla, shorter stamen with anthers degenerated into silk-like forms. Within 16-24°C, chimeric male sterile ecotype was appeared to be some anthers degenerated in various degrees, surviving pollen grains had a devoid viability with staining rate of 5.1-30.2% by TTC. Temperature lower then 16°C resulted in the male fertility restoration.Manifestations of pollen viability shows a similar trend. Microsporogenesis and megasporogenesis under higher temperature were cytologically observed. Abortion of the developing pollen grains took place at various stages, namely, sporogenous cell growth, microsporocyte formation, and uninuclear state, the mature pollen was irregular in shape and empty. No trace of embryo sac was present in ovules because of the arrested development of megaspores or small embryo sac with heterogeneous abnormal megaspores nonpolarly deposited. CaCl2 0.1mol L-1, CoCl21000mg L-1 and GA325mg L-1 from multi-dose treatment significantly enhanced seed set by offsetting nonviable pollen and female sterility. Though Spm with 0.5 mmol L-1 promoted pollen viability failed to promote seed production because of the failure of female fertility.
