【目的】由单片病叶发展成大小不等的发病中心是植物气传病害流行的重要阶段。条形柄锈菌小麦专化型Puccinia striiformis f. sp. tritici引起的小麦条锈病是世界范围内最重要的气传性病害之一。探究小麦条锈菌夏孢子在作物冠层内传播...【目的】由单片病叶发展成大小不等的发病中心是植物气传病害流行的重要阶段。条形柄锈菌小麦专化型Puccinia striiformis f. sp. tritici引起的小麦条锈病是世界范围内最重要的气传性病害之一。探究小麦条锈菌夏孢子在作物冠层内传播受到的影响因素,对了解气传性病害的流行具有重要意义。【方法】病原菌孢子在冠层内扩散会受到自身重力、风和寄主阻挡的影响。以小麦条锈菌为例,通过模拟自然沉降测定了病原菌孢子的重力沉降速度;比较了不同密度和角度阻挡物拦截的孢子数量差异;比较了麦田不同高度和不同种植密度下冠层风速的差异;在田间,模拟单片病叶向周边传播孢子的过程,分析了不同高度和水平距离下收集孢子数的差异。【结果】单个小麦条锈菌夏孢子的沉降速度范围为(1.491±0.055)cm/s;风速在小麦田随冠层高度的增加而增加,冠层上空风速显著高于冠层内风速,风速随小麦种植密度的增加而显著减少;阻挡物密度和角度与收集孢子数呈显著正相关;在小麦冠层中孢子扩散距离与孢子捕捉量呈极显著负相关。【结论】病原菌孢子重力沉降速度较慢,重力沉降对孢子在冠层内的水平传播距离影响较小。寄主叶片形态和种植密度可以调控孢子叶面定殖和孢子的扩散。研究结论有助于深入理解小麦条锈病的流行扩散模型和为探索植株形态避病机制提供理论依据。展开更多
Aims Plants control leaf phenology to maximize annual photosynthetic product.Although ferns play an important ecological role in many habitats,especially forests,their phenology traits have been poorly studied.Here,we...Aims Plants control leaf phenology to maximize annual photosynthetic product.Although ferns play an important ecological role in many habitats,especially forests,their phenology traits have been poorly studied.Here,we investigate the leaf phenology of two ferns of the forest understorey and analyse the relationship between the timing of leaf emergence and spore dispersal and the effect of between-year climatic variation.Methods We compared the leafing and sporing phenologies of two ferns with very large(>2 m),overwintering leaves:Culcita macrocarpa and Woodwardia radicans.We regularly monitored individuals of six popu-lations in the northwestern Iberian Peninsula during a 3-year study.We studied eight phenology variables:leafing start date,leafing end date,leaf expansion time,number of new leaves per individual,between-individual synchrony,within-individual synchrony,percentage of fertile leaves and spore release date.We also determined leaf mass per area(LMA)and gathered data on air temperature and humidity.Important findings Both C.macrocarpa and W.radicans produce few leaves(~2 leaves individual−1 year−1),which expand simultaneously for a very long period(from midwinter to early summer),are retained for more than 1 year(37 and 19 months,respectively)and have relatively high LMAs.Such traits,together with large leaf size,have also been found in seed plants from the forest understorey and represent adap-tations to this light-limited environment.Spores of both study ferns are simultaneously released in late winter,with little between-year variation caused by differences in air humidity.This remarkable similarity between species suggests that the convergence in tim-ing of leaf emergence favours the convergence in timing of spore dispersal.展开更多
文摘【目的】由单片病叶发展成大小不等的发病中心是植物气传病害流行的重要阶段。条形柄锈菌小麦专化型Puccinia striiformis f. sp. tritici引起的小麦条锈病是世界范围内最重要的气传性病害之一。探究小麦条锈菌夏孢子在作物冠层内传播受到的影响因素,对了解气传性病害的流行具有重要意义。【方法】病原菌孢子在冠层内扩散会受到自身重力、风和寄主阻挡的影响。以小麦条锈菌为例,通过模拟自然沉降测定了病原菌孢子的重力沉降速度;比较了不同密度和角度阻挡物拦截的孢子数量差异;比较了麦田不同高度和不同种植密度下冠层风速的差异;在田间,模拟单片病叶向周边传播孢子的过程,分析了不同高度和水平距离下收集孢子数的差异。【结果】单个小麦条锈菌夏孢子的沉降速度范围为(1.491±0.055)cm/s;风速在小麦田随冠层高度的增加而增加,冠层上空风速显著高于冠层内风速,风速随小麦种植密度的增加而显著减少;阻挡物密度和角度与收集孢子数呈显著正相关;在小麦冠层中孢子扩散距离与孢子捕捉量呈极显著负相关。【结论】病原菌孢子重力沉降速度较慢,重力沉降对孢子在冠层内的水平传播距离影响较小。寄主叶片形态和种植密度可以调控孢子叶面定殖和孢子的扩散。研究结论有助于深入理解小麦条锈病的流行扩散模型和为探索植株形态避病机制提供理论依据。
基金This research was supported by Xunta de Galicia Project PGIDT99PXI20301A.
文摘Aims Plants control leaf phenology to maximize annual photosynthetic product.Although ferns play an important ecological role in many habitats,especially forests,their phenology traits have been poorly studied.Here,we investigate the leaf phenology of two ferns of the forest understorey and analyse the relationship between the timing of leaf emergence and spore dispersal and the effect of between-year climatic variation.Methods We compared the leafing and sporing phenologies of two ferns with very large(>2 m),overwintering leaves:Culcita macrocarpa and Woodwardia radicans.We regularly monitored individuals of six popu-lations in the northwestern Iberian Peninsula during a 3-year study.We studied eight phenology variables:leafing start date,leafing end date,leaf expansion time,number of new leaves per individual,between-individual synchrony,within-individual synchrony,percentage of fertile leaves and spore release date.We also determined leaf mass per area(LMA)and gathered data on air temperature and humidity.Important findings Both C.macrocarpa and W.radicans produce few leaves(~2 leaves individual−1 year−1),which expand simultaneously for a very long period(from midwinter to early summer),are retained for more than 1 year(37 and 19 months,respectively)and have relatively high LMAs.Such traits,together with large leaf size,have also been found in seed plants from the forest understorey and represent adap-tations to this light-limited environment.Spores of both study ferns are simultaneously released in late winter,with little between-year variation caused by differences in air humidity.This remarkable similarity between species suggests that the convergence in tim-ing of leaf emergence favours the convergence in timing of spore dispersal.
