On the cover: Cold spells during flowering cause pollen sterility and major yield losses in most temperate climate rice growing areas of the world. The cold-tolerant upland rice variety R31 (Lijiangheigu; picture on cover by C. Davies, CSIRO Plant Industry) from the Yunnan province in Southern China is able to maintain pollen fertility and produce grains following prolonged exposure to cold temperatures.
In this issue Oliver et al. (pp. 1319-1330) show that in contrast to cold-sensitive rice, R31 is able to maintain sugar transport to the tapetum and young microspores under cold conditions. This is correlated with lower levels of the hormone ABA under both unstressed and stressed conditions. The difference in ABA homeostasis between cold-sensitive and cold-tolerant rice is due to both lower ABA biosynthesis and a faster rate of ABA catabolism. The cold-tolerant rice variety R31 may hold the key to the identification of the genetic basis of the control of ABA metabolism and provide opportunities for development of cold-tolerant rice varieties.
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