核桃砧穗生理状态对微枝嫁接成活的影响

Studies on Some Scion rootstock Physiological Indexes Related to Micrografting Survival of Walnut

核桃微枝嫁接是以子苗为砧木，以无根试管苗为接穗进行无性繁殖的一项新技术。子苗及试管苗生理状态对嫁接成活影响很大。真叶展开之前子苗内源细胞分裂素、生长素、含水量、葡萄糖、果糖均处于较高水平，嫁接易于成活（成活率为９０％）；真叶展开后，上述生理指标急剧下降，随之嫁接成活率也降低（成活率由８２．５％降至２５％）。上述生理指标较高、生理活性较强的试管苗有较高成活率（９１．４％），而干瘦细长、老态、叶卷曲的试管苗上述生理指标低，嫁接难以成活（成活率３７．１％）。

Walnut microshoot grafting is a new technique using juvenile seedlings as rootstocks and shoots in vitro as scions to propagate walnut cultivars.Some tests were carried out to focus on the relation between scion rootstock physiological states and grafting survival.Results were that during the first main leaf expanding,there was a significant change of the physiological metabolism in rootstock seedings,which was closely related to the grafting survival.Before the leaf was fully expanded,the level of cytokinin,auxin,water content,glucose and levulose in rootstock was higher,the grafting uniting can easily be achieved and the survival rate was more than 80.8%.After the leaf expansion,the physiological indexes went down and the grafting uniting became more and more difficult.The physiological state on shoots in vitro and their grafting also demonstrated that the tender,fast growing and strong shoots showed higher levels of the physiological indexes,and their grafting survival rate was higher,whereas the old,thin and longer shoots with twisted leaves showed lower levels of the indexes,and their grafting was difficult.