黑松三种菌根苗根系构型差异及其与生长的关系

Root architecture differences and their relationships with the growth of Pinus thunbergii seedlings with three kinds of ectomycorrhizae

为探讨林木不同菌根根系亚宏观结构对植物生长的影响,将黑松(Pinus thunbergii)分别接种黄色须腹菌(Rhizopogen luteous,简称Rl)、彩色豆马勃(Pisolithus tinctorius,简称Pt2)和美味牛肝菌(Boletus edulis,简称Be)3种外生菌根菌,研究了不同菌根苗根系构型的差异及其与黑松生长的关系。结果表明,黑松3种菌根苗的根系参数(主根长、侧根总级数、一级侧根数量及直径、吸收根分布的范围、吸收根的数量及比表面积等)均比对照有不同程度的增加,且与黑松生长呈一定的正相关性;黑松不同处理菌根苗的根系整体构型差异显著:在生长最好的Rl菌根苗根系中,主根与侧根间具不同夹角的一级侧根分布均衡,且横向生长(80～90°)的侧根较多,其它角度(60～80°和<60°)的一级侧根依次递减,使整个根系呈""型,有效扩大了根系吸收的空间范围;生长相对较差的Be菌根苗其根系不同角度的一级侧根分布不均或80～90°的侧根较少;Pt2菌根苗生长较好,其根系构型界于前二者之间;而生长差的对照苗根最少,几乎没有80～90°的一级侧根。由此可见,不同菌根菌可通过影响根系的结构发育而影响黑松苗木的生长。

To explore the effects of sub-macrosarchitecture of different root systems on seedling growth,Pinus thunbergii seedlings were inoculated with three ectomycorrhizal fungi： Rhizopogen luteous（Rl）,Pisolithus tinctorius（Pt2）,and Boletus edulis（Be）,respectively,to study the relationships of different ectomycorrhizal root architectures and the growth of Pinus thunbergii seedlings.Results showed that the root parameters（length of tap roots;total orders,numbers,and diameters of primary lateral roots;distribution range,number,and specific surface area（the ratio of surface area/volume） of absorptive roots） of Pinus thunbergii seedlings with three kinds of ectromycorrhizae increased at different degrees in comparison with non-inoculated seedlings（the control）,and were positively correlated with the growth of P.thunbergii.The root architectures were significantly different among the seedlings with different ectomycorrhizal roots.In the root system of the seedlings with Rl,which grew best,the primary lateral root with different branching angles to tap roots were appropriately distributed.The ones with 80-90° branching angles were more than those with other branching angles and the lateral roots with branching angles of 60-80° and 〈60° decreased descendingly,which made the root system ＂heart-shaped＂,and increased the uptaking spacial areas of the root system efficiently.The seedlings with Be grew relatively worse.Its root systems with different branching angles were not well distributed and the primary lateral roots with branching angles of 80-90° were less than those with other two ectomycorrhizal roots.The root architectures of the seedlings with Pt2 were between the ones with Rl and Be.The control seedlings developed the least roots,and almost no lateral roots with branching angles of 80-90°.Thus,ectoycorrhizal fungi had impact on the seedling growth of Pinus thunbergii by affecting the architectural development of its root systems.