High-Temperature-Induced Male Sterility in Crop Plants
Sakata, T., Oshino, T., Miura, S., Tomabechi, M., Tsunaga, Y., Higashitani, N., Miyazawa, Y., Takahashi, H., Watanabe, M. and Higashitani, A. 2010. Auxins reverse plant male sterility caused by high temperatures. Proceedings of the National Academy of Sciences USA 107: 8569-8574.
To further explore the subject and see what might be done to ameliorate the potential problem, Sakata et al. grew barley and Arabidopsis plants in growth cabinets maintained at normal day/night air temperatures for an initial period of time, after which HT treatments were begun and pertinent consequences observed. Then, at the conclusion of that stage of the study, they assessed the effects of exogenously applied auxin -- a phytohormone that orchestrates many physiological and development processes -- on HT injury of anthers during early development.
The ten scientists report that expression of certain auxin biosynthesis genes "was repressed by increasing temperatures," and that "under high temperature conditions, endogenous auxin levels specifically decreased in the developing anthers of barley and Arabidopsis." However, they also learned that "application of auxin completely reversed male sterility in both plant species."
Sakata et al. say their results "clearly suggest that a reduction in male tissue-specific auxin is the primary cause of HT injury," and that "the resulting abortion of pollen development and male sterility can be reversed by the application of exogenous auxin." Noting that "auxins have been used widely as potent and selective herbicides," they thus go on to say their results "show that auxin is useful for the promotion of plant fertility and maintenance of crop yields under global warming conditions." Thus, it is nice to know that if portions of the earth ever do warm to where high temperatures begin to significantly reduce crop yields via induction of male sterility, there is a substance that can function as both a herbicide and a fertility restorer that has already been successfully used for the former purpose and that can now provide dual benefits.