Phytopathology. 2003 Mar;93(3):256-61. doi: 10.1094/PHYTO.2003.93.3.256.
ABSTRACT The objective of this study was to determine the effect of silicon (Si) and rice growth stages on tissue susceptibility to sheath blight (Rhizoctonia solani Kühn) under controlled conditions. Rice plants (cv. Rio Formoso) were grown in pots containing low-Si soil amended with Si at 0, 0.48, 0.96, 1.44, and 1.92 g pot(-1) and inoculated with R. solani at the following days after emergence: 45 (four-leaf stage), 65 (eight-leaf stage), 85 (tillering), 117 (booting), and 130 (panicle exsertion). For plants inoculated with R. solani at all growth stages, Si concentration in straw increased as rate of Si increased from 0 to 1.92 g pot(-1). Concentration of calcium in the straw did not differ among plant growth stages. Although incubation period was not affected by the amount of Si added to the soil, this variable was shorter at booting and panicle exsertion stages. As the rates of Si increased in the soil, the total number of sheath blight lesions on sheaths and total area under the relative lesion extension curve decreased at all plant growth stages. The severity of sheath blight was lower at booting and panicle exsertion stages as the rates of Si increased in the soil. In general, plants grown in Si-nonamended pots and inoculated with R. solani were more vulnerable to infection at all growth stages, but especially at 45 days after emergence. Plant dry weights for inoculated plants increased as the Si rates increased from 0 to 1.92 g pot(-1). The greatest dry weight increases occurred for plants inoculated at booting and panicle exsertion stages. Si fertilization is a promising method for controlling sheath blight in areas where soil is Si deficient and when cultivars that exhibit an acceptable level of resistance to sheath blight are not available for commercial use.
摘要 本研究旨在确定硅（Si）和水稻生长阶段对受控条件下稻瘟病（腐霉菌）组织易感性的影响。在含有低 Si 土壤的盆中种植水稻（Rio Formoso 品种），并添加 0、0.48、0.96、1.44 和 1.92 g 盆(-1) 的 Si，然后在以下出芽后天数接种腐霉菌：45（四叶期）、65（八叶期）、85（分蘖期）、117（孕穗期）和 130（抽穗期）。对于在所有生长阶段都接种腐霉菌的植物，随着 Si 浓度从 0 增加到 1.92 g 盆(-1)，稻草中的 Si 浓度增加。稻草中的钙浓度在不同的植物生长阶段之间没有差异。虽然土壤中添加的 Si 量不影响潜伏期，但在孕穗期和抽穗期潜伏期较短。随着土壤中 Si 浓度的增加，在所有植物生长阶段，稻瘟病病斑总数和相对病斑扩展曲线下总面积均减少。在土壤中增加 Si 浓度时，稻瘟病的严重程度在孕穗期和抽穗期较低。通常，在 Si 非施肥盆中种植并接种腐霉菌的植物在所有生长阶段更容易受到感染，但在出芽后 45 天尤其如此。接种植物的植物干重随着 Si 浓度从 0 增加到 1.92 g 盆(-1)而增加。在接种于孕穗期和抽穗期的植物中，干重增加最大。Si 施肥是控制土壤 Si 缺乏地区稻瘟病的一种有前途的方法，并且当没有可用于商业用途的对稻瘟病具有可接受水平抗性的品种时。
