水稻不稔症發生主因之探討(II)

Abstract

在盆栽臺南5號水稻上接種消毒稻細蟎，朱消毒稻細蟎及稻葉鞘腐敗病菌。接有稻細蟎之處理均能產生標準之水稻不稔症病徵，按葉鞘腐敗病菌者則否。稻細蟎處理組水稻之不稔率、穗頸扭曲度、穗重、粒重及穗頸長等均顯著劣於葉鞘腐敗病菌處理組及對照組。分析不同生育期中水稻各部之可溶性蛋白質濃度、氮素含量及非結構性醣含量，發現稻細蟎處理組均與其他組有差異，尤其非結構性醣顯示水稻營養輸導在葉鞘部遭妥障礙，此可能為水稻不稔症之主要機制。 此試驗亦證明稻細蟎在水稻不稔症中占主要的地位。 Rice plants of cultivar Tainan No. 5 were planted on l/2,000a pots and were subjected to treatments of sterilized rice tarsonemid mites, unsterilized rice tarsonemid mites, or rice sheath rot fungus. Typical symptoms of empty grains (sterility) were induced on plants infested with rice tarsonemid mites but not on those infested with sheath rot fungus. The number of mites per tiller, sterility, panicle weight, average grain weight, length of panicle neck and degree of twisted panicle neck of the tarsonemid mite infected rice plants were significantly different from those of the sheath rot fungus infested rice plants and those of the check plants. The concentrations of soluble protein, nitrogen and total nonstructural carbohydrates in various plant organs were analyzed at several development stages. The tarsonemid mite infested rice plants were notably different from the others, especially in their total nonstructural carbohydrate content. This might be the important mechanism of the rice sterility. The implication of the rice tarsonemid mites in causing the empty grains of rice can be certified by this experiment.