中国松疱锈病菌锈孢子表面形态的扫描电镜观察*

中国10种松树的疱锈病菌锈孢子表面形态,在扫描电镜下观察并进行比铰,可归纳为两种类型:一是以单维管束松类的五针松的红松疱锈病菌(Cronartium ribicola)为代表,包括华山松和西伯利亚红松;另一是以双维管束松类的云南松疱锈病菌(C. flaccidum)为代表,包括樟子松、油松、赤松、马尾松、黄山松、思茅松等。孢子表面突起的形状及环纹层次是识别这两种锈疱子的主要特征。     

马尾松疱锈病菌及转主寄生的研究

马尾松疱锈病是一种严重的病害,病菌的性孢子、锈孢子(O、Ⅰ)阶段发生在马尾松(Pinus massoniana Lamb.)枝干上,夏孢子、冬孢子(Ⅱ、Ⅲ)阶段出现在玄参科的阴行草(siphonostegia chinensis Benth.)叶背、茎、萼片及果实上。取马尾松病干上的锈孢子人工接种,只有阴行草感病,产生与自然状态下相同的典型症状。该病菌性孢子器平展或不规则形,生于皮下;锈孢子表面塔状疣突的基部两层环纹很厚;冬孢子柱较小,长度很少超过800μm。因此认为,马尾松疱锈病菌是松芍柱锈菌[Cronartium flaccidum(Alb.et Schw.)Wint.]的阴行草专化型(C.flaccidum f.sp.siphonostegium)     

中国松疱锈病菌锈孢子表面形态的扫描电镜观察

中国10种松树的疱锈病菌锈孢子表面形态,在扫描电镜下观察并进行比铰,可归纳为两种类型:一是以单维管束松类的五针松的红松疱锈病菌(Cronartium ribicola)为代表,包括华山松和西伯利亚红松;另一是以双维管束松类的云南松疱锈病菌(C. flaccidum)为代表,包括樟子松、油松、赤松、马尾松、黄山松、思茅松等。孢子表面突起的形状及环纹层次是识别这两种锈疱子的主要特征。     

油松与赤松疱锈病病原及转主的研究

油松与赤松疱锈病是两针松类枝干上的重要病害,从油松和赤松主干病皮上取锈孢子分别向山芍药、芍药、返顾马先蒿、轮花马先蒿、长白茶藨子、东北茶藨子、香茶藨子和刺李进行室内和室外人工接种试验,终于在山芍药、芍药上接种成功,产生与自然状态下相同的典型症状。同样方法用夏孢子接种也都成功,在两种芍药上所产生的夏孢子堆与冬孢子柱以及夏孢子与冬孢子的形态也基本相同。由此可以肯定,油松疱锈病与赤松疱锈病是同一病原,病原菌为松芍柱锈菌[cronartium flaccidum(Alb·et Schw·)Wint]。取锈孢子用同样方法经多次在返顾马先蒿、轮花马先蒿、长白茶藨子、东北茶藨子、香茶藨子和刺李上接种,均未成功,因此认为这些植物与此两种疱锈病的发生无关,两种疱锈病在辽宁的转主寄主是山芍药(Paeonia obovata Haxim.)和芍药(P.lactiflora Pall.)。     

Studies on inoculation of aerial algae. I. Semi-mass culture and quantification of algal color of Klebsormidium flaccidum (Ulotrichales, Chlorophyceae) sprayed on to concrete board

This paper describes methods of semi-mass culture and the quantification of algal color sprayed on a concrete board of the alga Klebsormidium flaccidum (Küitzing) S. Mattox et Blackwell. The alga was cultured in 100 L tanks normally used for hatching brine shrimp, with aeration from the deepest parts of the slanting sides. Initially mean algal density increased rapidly and attained 9.1 times the original density after 4 weeks. Subsequently, increase of the algal density was slow, and the density became 16.1 times the original level after 8 weeks. The alga cultured in this study was sprayed on to a concrete board using an agricultural sprayer. The relationship between the algal density on the board and its color, expressed as L*a*b* color space, was quantified. The chromaticity was maximum as the algal density on the board was about 5 g/m², and the color was most vivid. When the algal density was more than 20 g/m², both the lightness and chromaticity changed slightly, and the color became dark green.     

The effect of dehydration and ion stress on carbon dioxide fixation in drought-tolerant phototrophic micro-organisms

Abstract Two cyanobacterial strains, Crinalium epipsammum SAB 22.89 and Tychonema sp. SAB 23.89 and the green alga Klebsormidium flaccidum were examined for their ability to fix carbon during controlled dehydration. Additionally the cyano-bacterium C. epipsammum was subjected to dehydration in the presence of a range of NaCl concentrations in order to discriminate between the effects caused by either matrix or ionic forces. K. flaccidum and C. epipsammun were proved to be able to maintain full carbon-fixing activity until the water content approached zero. Tychonema sp. appeared to reduce its activity in an immediate response to becoming dehydrated. The experiments have further substantiated the view on the strategy of these three drought-tolerant organisms to oscillating water availability. The cyano-bacteria, as the initial colonizers inhabiting the barren sand, are able to react quickly to changing water availability, thereby improving the water retention quality for the green alga. The latter organism will function well in an environment with improved water retention characteristics. C. epipsammum demonstrated extensive differences in carbon-fixing activities during dehydration in the presence of various concentrations of NaCl. This implies that when C. epipsammum is dehydrated in soils low in salt, the water availability, which is given by the matrix water potential, is determining the photosynthetic activity, whereas in more saline soils (equivalent to 50 mM NaCl and higher) the versatility towards osmotic adjustment plays an important role.