Effect of Uneven Distribution and Different Levels of Nematode Invasion on Symptom Development and Nematode Reproduction on Mung Bean

線蟲不均勻散佈及不同程度之侵入對綠豆苗根部病徵發展及線蟲繁殖之影響

蔡碧雲(Bie-Yun Tsai)

《植物病理學會刊》 19卷4期 (2010/12) Pp. 243-248

https://doi.org/10.6649/PPB.201012_19(4).0002

摘要

將400隻 Meloidogyne incognita 二齡幼蟲懸浮於1, 2, 4及8 ml 之水中，再接種於培養袋中之綠豆幼苗根系上，藉以製造線蟲散佈不均勻之狀況。一個根瘤內可出現一到三十六隻線蟲。在1, 2, 4及8 ml 之處理發現之最高線蟲密度分別為一個根瘤內有36, 24, 17及8隻線蟲。田間線蟲之散佈不均勻可想而知。本試驗結果顯示線蟲之不均勻散佈影響根瘤內線蟲之數目，因此用根瘤數或根瘤指數來評估根瘤線蟲病害無法顯示真正之嚴重性。另一個實驗將250, 500, 900及1800隻二齡幼蟲分別懸浮於4 ml之水中，再接種於培養袋中之綠豆幼苗根系上。當接種原由250隻線蟲增加到900隻時，每個根系之根瘤數及卵塊數隨之增加。增加接種原至1800隻線蟲時，根瘤數未顯著增加而卵塊數則顯著減少。本試驗結果顯示最佳繁殖效果所需之接種原濃度與最佳病徵發展所需之接種原濃度不同。除了了解M. incognita 與寄主綠豆之間的關係外，本試驗結果亦可對於與病害嚴重性及線蟲繁殖有關之研究工作之精確度有所貢獻。

關鍵字

Meloidogyne incognita ； 綠豆 ； 不均勻散佈 ； 繁殖

並列摘要

The uneven distribution of nematodes was created by inoculating 400 second-stage juveniles of Meloidogyne incognita in the aliquots of 1, 2, 4, and 8 ml of water to the root system of mung bean seedlings grown in culture pouches. The number of nematodes within a gall varied from 1 to 36 nematodes per gall. The highest density was 36, 24, 17, and 8 nematodes within a gall in the 1, 2, 4, and 8 ml treatments, respectively. The distribution of nematodes is conceivably uneven in a field situation. The uneven distribution of nematodes affected the number of nematodes within the galls and masked the severity of nematode invasion when the disease was assessed by the number of galls or galling index. Another experiment was conducted by inoculating 250, 500, 900, and 1800 nematodes in 4 ml of water to the mung bean seedlings grown in culture pouches. The numbers of galls and egg masses per root system increased as the inoculum level increased from 250 nematodes to 900 nematodes. Increasing the inoculum level to 1800 nematodes did not significantly increase the number of galls but decreased the number of egg masses significantly. The results showed that the optimum level of inoculum for maximum reproduction of nematodes was different from that for symptom development. In addition to the understanding of host-parasite relationship between M. incognita and mung bean, the results of this study may contribute to the improvement of the precision of researches involving disease severity and nematode reproduction by the awareness of the effect of uneven distribution and different levels of nematode invasion.

並列關鍵字

Meloidogyne incognita ； mung bean ； uneven distribution ； reproduction