内源CTK和IAA平衡对水稻分蘖芽休眠与萌发的影响

Effects of Endogenous Hormone Balance on Dormancy and Germination of Tiller Bud

研究水稻抽穗期分蘖休眠与萌发转换过程中CTK和IAA含量及CTK/IAA值的变化,探讨内源激素平衡对水稻分蘖的调控作用。采用外施6-BA打破分蘖芽休眠和去穗后外施IAA抑制分蘖芽萌发两种处理,创建分蘖芽休眠与萌发转换的材料,测定伸长节和伸长节分蘖芽中CTK和IAA的含量。6-BA处理打破了分蘖芽的休眠,显著提高了倒二节和倒二芽中CTK含量,降低了倒二节中IAA含量,对倒二芽中IAA含量影响不大,显著提高了节、芽中CTK/IAA值。去穗后外施IAA逆转了去穗对节、芽CTK含量提高效果,CTK含量维持在较低值,显著提高了倒二节中IAA含量,对倒二芽中IAA含量无显著影响,显著降低了节、芽中CTK/IAA值。CTK和IAA共同调控分蘖发生,较高的CTK/IAA值利于分蘖芽萌发,较低的CTK/IAA值使其休眠,节中CTK/IAA值在2.6-2.8,芽中CTK/IAA值在4.8-5.0,可作为分蘖芽休眠与萌发转换的临界指标。

The objection of this experiment was to study the changes of contents of CTK, IAA and the ratio of CTK/IAA during heading stage, and to investigate the regulation of endogenous hormones in rice tiller. Exogenous 6-BA and IAA were used to regulate the development of tiller buds, establish the transfer between dormancy and germination, and measure the contents of CTK and IAA in elongated nodes and tiller buds located at the elongated nodes. The exogenous 6-BA increased the CTK contents in nodes and tiller buds, decreased the IAA content in nodes had little effect in the content of IAA in tiller buds, significantly in-creased ratios of CTK/IAA in both nodes and tiller buds, and promoted the transfer from dormancy to germination. External IAA after removing panicle decreased CTK contents in nodes and tiller buds, which were maintained at a low level, increased the IAA content in buds, and significantly decreased the ratio of CTK/IAA in nodes and tiller buds, causing the transfer from germination to dormancy. Tiller development is determined by the balance between CTK and IAA, higher CTK/IAA ratio is benefit to the transfer from dormancy to germination, while lower CTK/IAA ratio inhibits the transfer. The ratios of CTK/IAA at 2.6-2.8 in nodes, 4.8-5.0 in tiller buds can be considered as the critical exponent of the transfer between dormancy and germination.