共查询到13条相似文献,搜索用时 62 毫秒
1.
苦豆碱对松材线虫的杀线活性 总被引:41,自引:4,他引:41
研究了苦豆草中苦豆碱对松材线虫的杀线活性,讨论了苦豆草生物碱在研究防治松材线虫病中的意义。使用含苦豆碱的培养基培养灰葡萄抱菌菌丝的生物测定方法,测定了苦豆碱对松材线虫的杀线活性,5天后培养基中苦豆碱的LC50=2.63×10-5g/ml,当浓度为1×10-4g/ml和2.63×10-5g/ml时,15天后苦豆碱的杀线率分别为99.9%和94.3%。 相似文献
2.
3.
4.
5.
基于汕头市濠江区已发现松材线虫病疫情的实际情况,针对该病的防治特点,结合汕头市各辖区山林的实际情况,从判断、预防、治理三个方面提出相应的防治对策,为科学防控该病在我市的扩散危害提供参考。 相似文献
6.
研究表明 :在松材线虫病发生区 ,其病害的扩展、流行与马尾松毛虫危害有着密切的关系。当年受马尾松毛虫危害的松林 ,枯死松树数量平均为 77 879株 /hm2 ,比未受松毛虫危害的松林 (对照 ) 17 2 73株 /hm2 ,多 35 1% ;次年 ,前者平均枯死松树达 2 0 4 8株 /hm2 ,为对照 2 89株 /hm2 的 6 0 8%。松毛虫危害加速松材线虫病流行的原因是 ,松毛虫危害松树 ,削弱树势 ;弱势的松树招引松墨天牛侵入并增殖加快松树死亡 ;次年大量天牛从“松毛虫危害松木”上羽化 ,侵染健康松林 ,导致松材线虫病进一步扩散和流行。由此认为松毛虫危害是促使松材线虫病流行的重要因子 ,防治松毛虫是控制松材线虫病流行的重要环节之一 相似文献
7.
8.
纤维素硫酸钠(Na-CS)具有突出的抗凝血活性,为了研究相对分子质量(Mw)与其抗凝血活性的构效关系,需要制备具有不同Mw。硫酸酯取代度相同的Na-CS系列类似物。本实验通过酸水解和凝胶过滤一离子交换联合分离的方法获得不同Mw。的Na-CS样品,以此为研究对象,考察了Na-CS的Mw。对其抗凝血效果和对凝血因子抑制作用的影响规律。结果表明,在一定范围内,随着Mw增大,Na-CS对活化部分凝血活酶时间(APPT)和凝血酶时间(TT)的延长作用增强,对凝血因子Ⅱa和Xa的抑制作用提高。 相似文献
9.
Juan Shi Youqing Luo Jiying Song Xiaosu Yan Ping Jiang Yijiao Wang 《Frontiers of Forestry in China》2007,2(4):466-473
Reported in this paper are our findings of the study on changes in species diversity of different Masson pine communities
after the invasion of Bursaphelenchus xylophilus (Steiner and Buhren) Nickle and subsequent and different removal disturbance management approaches. Based on the results,
the species diversity indices for the arbor layers of the different communities can be arranged in the following order (from
high to low): 1) broad-leaved stand after the removal of all infected pine trees in the pure pine stand in Fuyang; 2) lightly
infected Masson pine and Schima superba mixed stand in Fuyang; 3) uninfected stand mixture of Masson pine and Castanopsis fargesii as a control; 4) lightly infested pure Masson pine stand in Fuyang; 5) Quercus variables stand formed following the selective removal of infected pine trees from a mixed Masson pine and Q. variables stand in Zhoushan Islands; 6) pure young Masson pine stand formed following the removal of all infected pine trees from a
pure Masson pine stand; 7) pure Liquidambar formosana stand after the removal of infected pine trees from a pure pine stand in Zhoushan Islands; 8) a mixed stand consisting of
Pinus thunbergii and the Masson pine in Zhoushan Island; and 9) moderately infected Masson pine stand in Zhoushan Islands.
All the three diversity indices (R
0 = richness, H′ = Shannon-Wiener index, and E = evenness) for the shrub layer did not show any significant differences among the various communities except for the pure
pine stand in Zhoushan Island, which had the lowest diversity. The three indices for the herb layer of the pure young Masson
pine, Q. variables stand, and L. formosana stand were higher than that of other stands.
The integrated analysis showed that the Masson pine forest in different geographical situations and extent of damage had distinct
disparity, just as in different disturbance degrees and restoring manners.
We created the “index of disturbing intensity of stump and fallen woods” (IDISFW) to represent the degree of disturbance of
tree removal to plant diversity. We found that the relationship between the species diversity index and the IDISFW shows both
a lower and higher degree of removal disturbance that follows the “mid-altitude bulge” theory. Specifically, both excessive
and insufficient removal of infected trees will cause a decline of plant species diversity to a certain degree. Covariance
analysis indicated that different IDISFW had no significant effects on the species diversity of the arbor layer, but had different
impacts on that of the shrub and herb layers, and therefore can be used to assess changes in species diversity of different
Masson pine communities after the invasion of pine wood nematode.
__________
Translated from Chinese Journal of Applied Ecology, 2006, 17(7): 1,157–1,163 [译自: 应用生态学报] 相似文献
10.
松材中两种重要线虫比较的研究 总被引:6,自引:0,他引:6
松材线虫(Bursaphelenchus xylophilus)和拟松材线虫(B.mucronatus)被进一步证明是两个不同的种。除表现致病力差异外,形态上具有明显的不同特征,特别是前者交合伞卵圆形,后者平截形;生理学试验表明二者不能交配产生后代;生物化学方面的差异是:酯酶凝胶电泳中松材线虫酯酶带3条,迁移率分别为0.42、0.45、0.49;而拟松材线虫只1条酯酶带,迁移率为0.65。二者脂肪酸总量、不饱和度、短链和长链脂肪酸含量都有明显的差异。 相似文献
11.
针叶树木材流体纵向渗透性与其构造关系的理论分析 总被引:5,自引:0,他引:5
本文首次提出搭接面及侧面胞壁上纹孔在流体纵向渗透时的不同作用,并运用流体力学的原理,对针叶树木材流体纵向渗透性与其构造的关系进行了系统分析。结果表明:针叶树木材流体渗透系数等于早、晚材对其贡献之和,早、晚材对其的贡献,分别等于单位面积上流体流动路径数、管胞平均长度与纹孔膜膜缘厚度比值及纹孔膜微孔的比渗透性三者之积。经验证,研究结果与实测值较好的相符。 相似文献
12.
本文根据山东省省选12株毛白杨(Populus tomentosa Carr.)古树的38株无性系苗木资料,利用Fuzzy关系方程对苗高生长与7个形态性状进行模糊综合评判。结果表明,叶片长与苗高生长关系最密切。提出了应用形态性状估测苗高生长的GM(0,N)模型。 相似文献