板栗实腐病潜伏侵染和发病机理的研究  

Latent Infection of Fungal Pathogens and Pathogenesis of Chinese Chestnut Seed Rot

作　　者：贺伟[1] 尹伟伦[1] 沈瑞祥[1] 王晓军 

机构地区：[1]北京林业大学资源与环境学院,北京100083 [2]北京市怀柔区渤海镇林业站,北京101405

出　　处：《林业科学》2004年第2期96-102,共7页Scientia Silvae Sinicae

基　　金："十五"国家科技攻关"农林重大病虫害和农业气象灾害的预警及控制技术研究"项目 ;"林木病虫害环境协调性农药及其航空喷洒技术研究"课题 ;"经济林病害防治技术研究"子课题 ( 2 0 0 1BA5 0 9B12 0 2 ) ;北京林业大学振兴计划人才培养专项课题"板栗实腐病发病

摘　　要：在栗果发育和采后贮藏过程中 ,定期测定了栗果组织中酚类物质、可溶性糖、淀粉等物质的含量及带菌率和发病率 ,并测定了成熟栗果失水过程中种子生活力和几种生理指标的变化。在栗果发育阶段 ,总苞、花柱、果皮、种皮中酚类物质的含量 ,均在 1mg .g- 1 鲜重以上 ,明显超过离体条件下邻苯二酚对 4种病菌菌丝生长产生显著抑制作用的 0 5mg.g- 1 的浓度 ;花柱、栗苞、果皮组织中均有一定数量的病菌分布 ,但不表现症状 ;这表明栗果发育期栗实腐病菌处于潜伏状态与栗果组织中高含量的酚类物质有关。栗果成熟时 ,果皮中酚类物质含量急剧减少 ,减弱了对病菌的抑制作用。采收后种子随含水量减少 ,种子发芽指数下降 ,脂质过氧化物含量增加 ,细胞膜透性增大 ;种子失水超过 1 0 %时 ,种子发芽率开始下降 ,自由基清除剂超氧物岐化酶 (SOD) ,过氧化物酶 (POD)活性明显降低 ,并诱发出病害。病害发生的临界含水量与种子发芽率开始下降时的含水量值相近 ,表明种子失水降低了种子的抗病力。随着淀粉水解 ,可溶性糖含量增加 ,病原菌解除潜伏 。Incidence of the disease and the rate of pathogen carried and substances including phenolic compounds, soluble sugar, and starch in fruits of Chinese Chestnut were tested regularly during the development of chestnut fruits and post harvest storage period. The variation of viability and the related physiological index of seeds in the process of water loss, and the effects of those variation on the activity of pathogens inside the seeds were also tested. The content of phenolic compound in involucre, style, pericarp and seedcoat of chestnut fruit reached 1 mg·g -1 of fresh weight, exceeded the concentration of 0 5 mg·g -1 , which was proved to be the concentration for markedly inhibiting the mycelial growth of the pathogens in vitro. Pathogens were isolated from the tissue of involucre, style, pericarp and seedcoat but no symptoms appeared. This indicated that high contents of phenolic compounds in chestnut fruit contributed to the latent infection of the pathogens of Chinese Chestnut seed rot. On maturation of chestnut seeds, the content of phenolic compounds in pericarp decreased sharply and reduced the inhibiting effects to the pathogens inside. As the water content of seeds decreased the seed germination index declined, and the content of malondialdehyde (MDA) increased steadily, and the relative conductivity of soaking solution, in which the Chinese Chestnut seeds soaked, were increased markedly. When the rate of water loss exceeded ten percent, the germination rate of seeds started to decline, and the activities of free-radical scavenging enzymes (superoxide dismutase and peroxidase) decreased markedly,and the seed rot was induced. The fact that the critical moisture content for pathogenesis was close to the moisture content, when the germination rate of seeds started to decline, indicated that the water loss in seed reduced the resistance of seed. Accompanied by starch hydrolysis and the quantity of soluble sugar increasing, the pathogens relieved from latent infection and caused the seed rot.

关 键 词：板栗实腐病 潜伏侵染 发病机理 酚类物质 可溶性糖 淀粉 带菌率 种子生活力 

分 类 号：S436.64[农业科学—农业昆虫与害虫防治]