山核桃异砧嫁接苗生长特性观察

为进一步了解砧木对山核桃Carya cathayensis接穗生长的影响,明确不同砧木嫁接苗生长差异的原因。本实验以山核桃本砧嫁接苗为对照,以美国山核桃C. illinoensis和湖南山核桃C. hunanensis为砧木的嫁接苗作为主要研究材料,分析比较其存活率、接穗生长量、叶片叶绿素荧光特性及愈合部输导能力等方面差异,探讨异砧嫁接促进山核桃接穗生长的可能原因。研究发现:(1)以美国山核桃和湖南山核桃为砧木时,嫁接成活率为90.45%和92.66%,而本砧嫁接的成活率仅为76.34%,且后期出现大量死亡现象;(2)以湖南山核桃为砧木的嫁接苗,新梢生长量、节间长度和复叶数,显著优于其余二者,其中本砧嫁接苗生长最差,单叶长和宽也最小,说明异砧嫁接有促进山核桃接穗生长的作用;(3)以湖南山核桃为砧木的嫁接苗叶绿素含量显著高于其余二者,在一定程度上表明其光合作用更强;(4)利用划走式切片仪将砧穗连接处切片观察,从切片情况可知,以湖南山核桃为砧木的嫁接苗再生组织中单位面积的导管数最多,且愈合较好;本砧嫁接苗导管数最少,且愈合较差。通过研究笔者推测山核桃异砧嫁接砧穗连接处愈合较好、再生组织间导管数多是其成活率高的原因,且异砧嫁接对山核桃接穗的生长有促进作用。

Observation on Growth of Carya cathayensis Grafted on Different Rootstocks

On April 2, 2017, scions of 1-year Carya cathayensis branch were collected in Lin’an, Zhejiang province, and were grafted on rootstocks of 2-year C. illinoensis and C. hunanensis seedlings. The results showed that survival rate of seedlings grafted on C. illinoensis and C. hunanensis topped 90.45% and 92.66%, while that on C. cathayensis had only 76.34%. Shoot growth, internode length and compound leaves of seedlings grafted on C. hunanensis had the best result, respectively 70.40 cm, 6.78 cm and 10.60 blades, and that grafted on C. cathayensis had the last effect. Chlorophyll a and b content and carotenoid content in fresh leaves of seedlings grafted on C. hunanensis topped 1.406 mg·g-1, 3.951 mg/g and 1.143 mg·g-1. Microexamination on sections from grafting part demonstrated that unit area vessel numbers in callus tissue of seedling grafted on C. hunanensis had 124.8, that on C. illinoensis had 94.8 and that on C. cathayensis had only 62.