不同收获期的扭黄茅种子和植株抗旱性分析

Analyses on the Drought Resistances of the Seeds Harvested at Different Period and Plants of Heteropogon contortus

温室控水条件下,以鸭茅、高羊茅为对照,采用4个不同收获时期的扭黄茅种子进行盆栽试验,分别测定了牧草出苗率、株高、株鲜重、叶绿素含量、光合作用指标等指标,并进行了统计分析。结果表明:不同采收期扭黄茅种子的含水量、种子干重存在差异,从而对种子萌发、植株生长以及植株抗旱性方面产生影响,这一现象和扭黄茅的开花习性有关。推测扭黄茅的净光合速率降低原因为干热胁迫初期气孔限制因素起主导作用,胁迫中后期非气孔限制因素起主导作用。对扭黄茅、鸭茅、高羊茅3种牧草进行抗旱性综合评价,3种牧草的抗旱性强弱从高到低,存在扭黄茅>高羊茅>鸭茅的趋势。

The seed of Heteropogon contortus that harvested respectively at 4 different periods was cultured in greenhouse,Dactylis glomerata and Festuca arundinacea were chosen as comparative materials.The rate of emergence,plant tall,fresh weight and chlorophyll content photosynthesis indices were determined and statistically analyzed.The results showed that there was difference of the seed moisture and seed dry weight among different harvest stages,which had effect on seed emergence,plant growth and drought resistance.The difference was related with the character of blooming of H.contortus.It was estimated that the photosynthesis rate of H.contortus was related with stomatal limitation and non-stomatal limitation,the stomatal limitation factor was the leading role in the initial stress period,the non-stomatal limitation factor was the leading role in the middle-late stress period.The drought resistance of the three sorts of pasturages was comprehensively evaluated by the method of the subordinate function,and their drought resistances were shown to decrease in the order of H.contortus,D.glomerata and F.arundinacea.