断根与外源细胞分裂素诱导去叶黑麦草耐牧性的研究

为了研究牧草的持续再生性机制，通过盆栽试验，从黑麦草多次去叶后根系对叶片生长的影响方面，设4个处理：（1）不断根未喷施细胞分裂素，（2）断根未喷施细胞分裂素，（3）不断根喷施细胞分裂素，（4）断根喷施细胞分裂素。结果表明：断根和多次去叶均能降低新生叶片和根系的生物量。多次去叶能引起叶中的赤霉素和脱落酸含量的升高，生长素含量以及玉米素核苷(ZR)含量的降低。多次去叶条件下，喷施外源细胞分裂素能促进叶片中ZR含量及其生物量的增加。相关性分析表明，多次去叶条件下叶中ZR含量与其生物量呈显著性的正相关关系。总之，多次去叶条件下新生叶片中的细胞分裂素含量是影响去叶黑麦草持续再生性的关键因素。

The Influence of Root-breaking and Exogenous Cytokinin Spraying on the Grazing Tolerance of Ryegrass

The aim was to study the mechanism of continuous regeneration of ryegrass.By pot culture,the study investigated the improving continuous regeneration of ryegrass in terms of the influence of roots on leaves under frequent defoliation.The study consisted of four treatments：（1） no root breaking without spraying cytokinin,（2） root breaking without spraying cytokinin,（3） no root breaking with spraying cytokinin,and（4） root breaking with spraying cytokinin.The results showed that root breaking or frequent defoliation resulted in low biomass of the newly grown leaves and roots.Frequent defoliation increased gibberellic acid（GA） and abscisic acid（ABA） content,decreased indole-3-acetic acid（IAA） content and decreased the ZR content in newly grown leaves.Spraying with exogenous cytokinin promoted the increase in ZR content and newly grown leaf biomass under frequent defoliation.There were a significant positive correlation between ZR content and biomass in newly grown leaves under frequent defoliation.In general,under frequent defoliation cytokinin plays an important in improving continuous regeneration of ryegrass.