EFFECTS OF INFECTION BY PYTHIUM SPP ON ROOT-SYSTEM MORPHOLOGY OF ALFALFA SEEDLINGS
EFFECTS OF INFECTION BY PYTHIUM SPP ON ROOT-SYSTEM MORPHOLOGY OF ALFALFA SEEDLINGS
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DOI：
10.1094/phyto-85-430
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发表时间：
1995-04-01
期刊：
影响因子：
3.2
通讯作者：
MIHAIL, JD
中科院分区：
文献类型：
--
作者：
LARKIN, RP;ENGLISH, JT;MIHAIL, JD
采用形态计量学和拓扑评价方法，在温室试验中对不同毒霉侵染苜蓿幼苗根系形态进行了评价。紫花苜蓿幼苗受黄皮霉（pyium spp）侵染后，根系生长减慢，根系构型发生变化，尤以黄皮霉（P. ultimum）和不规则黄皮霉（P. irregulum）影响最大。根系形态参数（包括根系总长度和根阶总数）以及根系大小、海拔高度和总外径长度等拓扑参数的减少表明，与未感染植株相比，受侵染植株的根系总体大小和复杂性更小。根系分支结构也受到影响，与未感染的根系相比，感染的根系分支程度较低，分支的阶数较少，分支模式更倾向于单足型。尽管最后一株、不规则一株和森林一株的分离株在出苗期前和出苗期后都引起了大量的衰减，但森林一株的根系形态没有引起可测量的变化。相比之下，黄杨引起了根系大小和分支复杂性的严重减少，而黄杨引起的阻尼程度较轻，但也引起了根系形态的实质性变化。分离株和分离株对根系生长和形态没有影响。在土壤中施用甲螨灵可以有效地减少这些病原菌的影响，而在种子中施用甲螨灵效果较差。利用体系结构分析方法，首次定量评价了根系病原菌对根系分支结构的影响。
Root system morphology of alfalfa seedlings infected by various Pythium spp. was evaluated in greenhouse experiments using morphometric and topological assessment methodologies. Infection of alfalfa seedlings by Pythium spp., particularly P. ultimum and P. irregulare, resulted in reductions in root system growth and changes in root system architecture. Reductions in root system morphological parameters, including total root system length and total numbers of root orders, as well as the topological parameters root system magnitude, altitude, and total exterior path length, indicated overall smaller root system size and complexity in infected plants compared with noninfected plants. Root system branching structure also was affected, with infected root systems developing with a lower degree of branching than noninfected root systems, as represented by fewer orders of branching and a more monopodial type of branching pattern. Although isolates of P. ultimum, P. irregulare, and P, sylvaticum all caused substantial pre- and postemergence damping-off, P. sylvaticum caused no measurable change in root system morphology. In contrast, P. ultimum caused severe reductions in root system size and branching complexity, and P. irregulare, which caused less-severe damping-off, also caused substantial changes in root system morphology. Isolates of P. dissotocum and P. torulosum had no effect on root system growth or morphology. Metalaxyl applied to the soil was effective in reducing the effects of these pathogens, whereas metalaxyl seed treatment was less effective. Use of architectural analysis methods enabled the quantitative assessment of the impact of root pathogens on root system branching structure for the first time.