杨盘单格孢菌〔Marssonina populi (Lib.)Magn.〕的两种专化型

<正>华东地区杨树黑斑病是由杨盘单格孢菌(Marssonina populi)引起的,病害主要为害白杨派树种和黑杨派树种以及它们的杂交种。杨盘单格孢菌根据孢子萌发的形态、生理和寄主范围可以分为两个专化型。单芽管专化型(M.populi f.sp.monogermtubi)的分生孢子萌发时产生 1个芽管;在蒸馏水中基本上不萌发,在自来水中萌发良好,2小时开始萌发,9小时即达高峰;孢子萌发温度为12-28℃;孢子表面无萌发抑制物质;寄主以白杨派树种及派内杂交种为主。多芽管专化型(M.populi f.sp.multigermtubi)的分生孢子萌发时产生1-5个芽管,多为2-3个;蒸馏水中能萌发但不及自来水中萌发率高;在自来水中4小时开始萌发,13小时以后才达高峰;萌发温度为16-32℃;孢子表面有水溶性萌发抑制物质,须用清水洗涤后才能萌发;寄主以黑杨派树种及派内杂交种和黑杨派与青杨派杂交种为主。两种专化型用孢子萌发试验即可鉴别。

TWO SPECIALIZED FORMS OF MARSSONINA POPULI (LIB.) MAGN.

In the region of East China, Marssonina leaf blight of poplars is caused by Marssonina populi (Lib.) Magn. The blight induces high mortality of poplar seedlings and premature defoliation of plantation and shade trees. According to the observations carried out the causal fungus on different host poplars can bo divided into two specialized forms. For the first form, its conidia germinates one germtubc well in tap water but seldom germinates in distilled water; the germination temperature ranges from 12° to 28°C; no water-soluble inhibitor of germination is to be detected on the surfaces of fleshly collected spores; Populus adenopoda, P. tomentosa and the hybrids of the poplars of Section Leuce are subject to be infected in nature and in artificial inoculation of detached leaves in vitro. This form is named Marssonina populi f. sp. monogermtubi. The name of the other form is marssonina populi f. sp. multigermtubi, the conidia of which germinates 1-5, mostly 2-3 germtubes in both tap and distilled water; the germination temperature ranges from 16° to 32°C; a water-soluble germination-inhibiting substance is to be detected, so only after washing will spores have a high potential for germination. The main natural hosts of this form include many species of Section Aigeiros and their hybrids, and hybrids of Section Aigeiros with Section Tacamahaca, but infection has never been found on species of Section Taca-mahaca such as P. cathayana, P. maximowiczii and P. yunanensis. By artificial inoculation of detached leaves, almost all the poplars examined including some species of Section Leuce and Section Tacamahaca are susceptible to infection.