PATHOGEN MORTALITY OF TROPICAL TREE SEEDLINGS - EXPERIMENTAL STUDIES OF THE EFFECTS OF DISPERSAL DISTANCE, SEEDLING DENSITY, AND LIGHT CONDITIONS
PATHOGEN MORTALITY OF TROPICAL TREE SEEDLINGS - EXPERIMENTAL STUDIES OF THE EFFECTS OF DISPERSAL DISTANCE, SEEDLING DENSITY, AND LIGHT CONDITIONS
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DOI：
10.1007/bf00396763
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发表时间：
1984-01-01
期刊：
影响因子：
2.7
通讯作者：
KELLY, CK
中科院分区：
文献类型：
--
作者：
AUGSPURGER, CK;KELLY, CK
本文介绍了两个试验的结果，这些试验旨在确定散布距离、苗木密度和光照条件对热带树苗病原菌引起的死亡的相对重要性。在巴拿马巴罗科罗拉多岛进行的田间试验表明，散布距离的增加和苗木密度的减少都会降低悬铃木幼苗的立枯病水平，而且这两个因素是相互作用的。病原菌活性在不同地点差异很大，当苗木在其亲本树周围建立时，比在其他同种树周围更容易受到疾病的影响。第二个试验采用了18个散风树种的盆栽苗木，暴露在两个水平的日照和苗木密度下。与光隙相似的环境条件似乎显著降低了病原菌的活性。苗木密度越高，病情越严重，尤其是在遮荫条件下。18个种中的16个种的幼苗。经历过病原体引起的死亡，但死亡人数差异很大。种子重量不能很好地预测一个物种对病原体的易感性。成年木材密度是生长速度和演替状态的指标，与树种对病原体的脆弱性呈负相关。快速生长、定植的物种，其幼苗需要光隙，缺乏能够耐荫和躲避苗木病原体的强大物种。这些结果在种子传播作为一种逃避苗木病原体的手段的背景下进行了讨论。
Results are presented of 2 experiments designed to identify the relative importance of dispersal distance, seedling density, and light conditions on pathogen-caused mortality of tropical tree seedlings. The field experiment on Barro Colorado Island, Panama, demonstrated that both an increase in dispersal distance and a decrease in seedling density reduce levels of damping-off disease among seedlings of Platypodium elegans, and that the 2 factors interact. Pathogen activity varied significantly among sites, and seedlings to be more vulnerable to disease when establishing around their parent tree than around other conspecific trees. The 2nd experiment in a screened enclosure used potted seedlings of 18 wind-dispersed tree species exposed to 2 levels of sunlight and seedling density. Environmental conditions similar to those in light-gaps seemed to significantly reduce pathogen activity. High seedling density increased disease levels, especially under shaded conditions. Seedlings of 16 of the 18 spp. experienced pathogen-caused mortality, but in widely varying amounts. Seed weight was not a good predictor of a species'' vulnerability to pathogens. Adult wood density, an indicator of growth rate and successional status, was inversely correlated with a species'' vulnerability to pathogens. Fast-growing, colonizing species, whose seedlings require light-gaps, lacked strong species able to tolerate shade and escape seedling pathogens. These results are discussed in the context of seed dispersal as a means of escaping from seedling pathogens.