Перегляд вихідного коду сторінки Quite Interesting Actions All UNC2881 Fanatic Ought To Try Out

e. freezing and chilling temperatures even for a short period (Zinn et al. 2010; Parish et al. 2012). In the present study four critically sensitive periods of flower development in F.�� ananassa were identified (Fig.?5) by subjecting flower buds at different stages [http://en.wikipedia.org/wiki/Diglyceride diglyceride] to chilling. Figure?5. Low-temperature critical periods (grey bands) in days before anthesis of strawberry flower development, detected after subjecting flowers buds at different developmental stages to chilling (24 h at 2 ��C). Periods were identified when strawberry ... The earliest stage showing susceptibility to low temperatures is male gametophyte development at stage 8 or before (20�C17 days before anthesis). This was revealed as a significant decrease (up to 82 %) in the number of pollen grains, and by a 4-fold increase of the percentage of non-viable pollen (Fig.?5). These results demonstrate that temperature [http://www.selleckchem.com/products/GDC-0941.html find more] cultivated [http://www.selleckchem.com/products/AZD0530.html www.selleckchem.com/products/AZD0530.html] strawberry is also sensitive to low temperature. This is in agreement with recent studies reporting signs of cytomixis of PMCs at prophase I, contributing to the death of PMCs, as a consequence of chilling (Barton et al. 2014). A third chilling sensitive stage occurs 10�C7 days before anthesis (stages 10b and 11a). Dame here decreased the number of pollen grains by 73 %, indicating that microspore development and tapetum degeneration are affected (Parish et al. 2012). Pollen sterility induced by cold might be due to a disruption of sugar metabolism in the tapetum, ultimately abolishing starch accumulation (i.e. energy reserves) and exine secretion by the pollen grains (Oliver et al. 2005). Finally, chilling 5�C3 days before anthesis (stage 11b) decreased the percentage of germinated pollen grains by 49 % and increased percentage of non-viable pollen by 1.7-fold. This indicates that microspore mitotic processes are being disrupted (Satake and Hayase 1970), an effect probably associated with microtubules disassembly during mitosis. Microtubules are known to be highly thermosensitive (Hepler and Hush 1996). On the other hand, chilling decreased the number of pollen grains by 60 %. This may be a result of physical disruption of pollen grains and of cell death induced by deleterious effect of low temperatures (Zinn et al. 2010).