冬小麦(Triticum aestivum)分蘖冗余生态学意义以及减少冗余对水分利用效率的影响

通过盆栽试验,以旱作冬小麦(Triticum aestivum)为材料,分别在拔节和抽穗期对分蘖进行人工干扰,来模拟不可预测的自然干扰,对冬小麦分蘖冗余的生态学意义以及减少这些冗余对水分利用效率影响进行研究.设置3个处理:从拔节期开始剪去所有小的分蘖,仅保留主茎和一个大的分蘖(A);在拔节期剪去主茎和两个大的分蘖,保留所有小的分蘖(B);在孕穗期剪去主茎和有效分蘖,保留无效分蘖(C).没有被干扰的植物作为对照(CK).通过花期测定叶片的叶绿素含量、叶绿素荧光参数、气孔导度和蒸腾速率等生理指标来评价植物的生理与生化活性.结果显示,在拔节期和抽穗期去除主茎和大蘖后,无效分蘖的生理活性被激活,开始执行有效分蘖的功能.到花期时,这些无效分蘖已经在生理活性上满足了补充和替代有效茎的要求.虽然株高和穗的整齐度、穗数和产量显著下降,但并没有防碍小麦的繁衍子代,因此,正是这些由早期"无效分蘖"补充而来的有效茎,避免了小麦绝种的风险.而在拔节期去除无效分蘖后,对小麦产量没有显著影响,但提高了水分利用效率,和对照相比水分利用效率提高了10%.因此,可以认为小麦在分蘖上存在着对水分利用不利的生长冗余,减少这些冗余有望节约用水、提高作物的水分利用效率.

Ecological significance of redundancy in tillers of winter wheat(Triticum aestivum)and effect of reducing redundancy on water use efficiency

A pot experiment was conducted to study the ecological significance of redundancy in tillers of winter wheat and effect of reducing redundancy on water use efficiency by clipping some tillers of winter wheat and simulating environmental disturbance at two growing stages(jointing stage and heading stage).Plants were subjected to three treatments:(A) the main stem and the biggest tiller were retained,clipping all other tillers at jointing stage;(B)all small tillers were retained,clipping main stem and two bigger tillers at jointing stage;(C)all barren tillers were retained,clipping main stem and fertile tillers at heading stage.The undisturbed plants were considered the controls(CK).At flowering stage,the chlorophyll content,chlorophyll fluorescence parameters,stomatal conductance and transpiration rates were measured to evaluate the physiological and biochemical activity of winter wheat.The results showed physiological and biochemical activity of barren tillers could restore to the level of fertile shoots after clipping the main stem and big tillers.It is clear that barren tillers can afford to supplement and substitute for fertile shoot in physiological and biochemical activity at flowering stage.At maturity,although the uniform degree of plant height and spike weight,spike number and grain yield decreased significantly,which had no influence on propagation of the next generation.Therefore,tillers redundancy ensured that the disturbed plant can propagate and decrease the risk of plant extinction.After clipping barren tillers,the yield was unaffected,but water use efficiency for grain yield increased by about 10% compared to the control.It is shown that tiller redundancy is unfavorable to water use efficiency while reducing redundancy by taken some suitable agricultural measures is helpful to improve water use efficiency of crop.