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苹果树为藏东南地区经济林的主要树种,近年来锈病危害严重。以藏东南地区苹果树为研究对象,基于野外调查,采用扩散系数C、Morisita指数I、Cassie指标Ca、平均拥挤度M*、Lloyd聚块性指标、负二项参数K、Iwao回归分析法、Taylor幂指数方法,研究了藏东南工布自然保护区苹果树叶片上锈病的空间分布格局规律。结果表明:苹果树叶片上锈病斑数量表现为树中部>树下部>树上部,树西面>树东面>树北面>树南面。锈病斑数量在苹果树叶片上中部占39.33%,其中左中部占19.32%、右中部为20.01%;叶下部占31.53%,其中左下部为15.37%、右下部为16.16%;叶上部占29.14%,其中左上部为14.70%、右上部为14.44%。叶左边占49.39%,右边占50.61%。苹果树叶片上锈病斑主要以10~40个聚集的形式存在。以30≤b<40为最多,锈病斑数量占总锈病斑数比率的17.36%。苹果树叶片上锈病斑空间分布呈聚集型,但聚集强度不大,锈病斑个体群大小不是一成不变的,而是随着锈病斑密度的增加而增大,其平均个体群大小为48.42。苹果树叶片上锈病斑的空间格局IwaoM*-m回归模型为M*=0.997 2+5.686 8m(R~2=0.999 9),Taylor幂模型为log(S~2)=0.148 3+1.633 2log m(R~2=0.956 8),2个模型均判定锈病斑在所有密度下均呈聚集分布,随着锈病斑密度增大,聚集强度也增大。
Apple trees are the major species of economic forest in southeastern Tibet. In recent years, rust has been seriously endangered. Taking the apple tree in southeastern Tibet as the research object, based on the field investigation, the diffusion coefficient C, Morisita index I, Cassie index Ca, average crowding degree M *, Lloyd clustering index, negative binomial parameter K, Iwao regression analysis, Taylor power index method to study the spatial distribution pattern of apple leaf rust in the South Tibet Nature Reserve. The results showed that the number of rust spots on the leaves of apple tree showed as middle part of tree> lower part of tree> upper part of tree, west of tree> east of tree> north of tree> south of tree. The number of rust spots accounted for 39.33% of the middle leaves of apple trees, of which 19.32% were in the left middle part and 20.01% in the middle right part, 31.53% in the lower part of the leaves, 15.37% in the lower left part, 16.16% in the lower right part, 29.14% The upper left is 14.70% and the upper right is 14.44%. Leaves on the left accounted for 49.39%, on the right accounted for 50.61%. The rust spots on the leaves of apple trees mainly exist in the form of 10 to 40 aggregates. With 30≤b <40 as the most, the number of rust spots accounted for 17.36% of the total number of rust spots. The distribution of rust spots on the leaves of apple trees was aggregative, but the aggregation intensity was not so great. The size of individual rust patches was not constant, but increased with the increase of the rust spot density. The average individual size was 48.42. The spatial pattern of the rust spots on the leaves of apple trees was log (S 2) = 0.148 3 + 1.633 2log m (I), and the IwaoM * -m regression model was M * = 0.997 2 + 5.686 8m (R ~ 2 = 0.999 9) R ~ 2 = 0.956 8). Both models determined that the rust spots were aggregated and distributed at all densities. As the density of rust spots increased, the aggregative intensity also increased.