礦物元素對白花芥藍黑斑病發生的影響

Effect of elements on disease severity of black spot of Chinese kale

鍾文全(W. C. Chung) ； 黃振文(J. W. Huang)

《植物病理學會刊》 2卷2期 (1993/06) Pp. 78-87

https://doi.org/10.6649/PPB.199306_2(2).0004

摘要

在田間與網室，感染Alternaria brassiccola的白花芥藍植株，其各位葉之黑斑病罹病度與葉齡間呈正相關；此外，利用傷口接種法證明病原菌感染幼葉的病斑數目與罹病度均較老葉少且輕微。由原子光譜儀、紫外光光譜儀和Microkjeldahl法分析比較白花芥藍各位葉的營養元素含量，顯示老葉含氮量較低且各位葉的氮含量與其葉序間的關係是Y=9.5 + 0.4X-0.18X^2 (R^2 = 0.72 , P ＜ 0.0001)。進一步統計分析發現白花芥藍第六位葉的黑斑病罹病度與其葉含量呈負相關Y = 9.7-0.1X (R^2=0.59, P ＜ 0.0001)。此外，各位葉的其他營養元素如：磷、鉀、鈣、鎂、錳、鐵、銅、鋅與硼之含量與植株黑斑病罹病度間存在有不等程度的相關性，惟彼此間的相關變異係數值偏低或不穩定。在網室，比較施用肥料對黑斑病發生的影響，發現白花芥藍施用150 ppm或更多之氮肥時，可減輕A. brassicicola的爲害，但卻使A. brassicae的爲害增加；若施用≧100 ppm或≧250 ppm磷肥時，分別可降低A. brassicicola或A. brassicae爲害白花芥藍的罹病度；至於鉀肥的施用量需高於200 ppm才可有效降低兩菌爲害植株的百分率。進一步以水耕栽培法研究,發現白花芥藍缺錳與鋅元素時，可促進葉片病斑的擴展。顯然，白花芥藍植物體內的營養元素含量可影響這兩種菌爲害葉片的罹病度。

關鍵字

白花芥藍黑斑病 ； 礦物元素 ； 肥料

並列摘要

In the greenhouse and field, disease severity of black spot of Chinese kale, caused by Alternaria brassicicola, was positively correlated with leaf age (leaf positions from first to eighth) When the second and seventh leaves were wound inoculated with the pathogen, the lesion number and disease severity in the second leaves were significantly less than those in the seventh leaves. Foliar analyses indicated that amount of nitrogen element in leaves was highly correlated (Y= 9.5+ 0.4X 0.18X^2, R^2- 0.72, P ＜0.0001) with leaf positions from first Lo eighth. The disease severity of the sixth leaves was negatively correlated (Y= 9.7- 0.1X, R^2= 0.59, P＜ 0.0001) with amount of foliar nitrogen element. Chinese kale grown in so amended with 150 ppm or more of Urea-N greatly decreased the disease severity of black spot caused by A. brassicicola, but the reverse occurred by A. brassicae. Resistance of Chinese kale plants to A brassicicola and A. brassicae was enhanced when they were grown in so amended with ≧ 100 and ≧ 250 ppm of P_2O_(5-) P, respectively. Application of 200 ppm or more of KCl-K to soil also increased the resistance of Chinese kale plants to the disease In hydroponic cultivation with Hoagland's solution, deletion of manganese element increased the number of expanded lesions ＞ 5.1 mm diam.). This study suggests that mineral elements may affect the disease severity of Chinese kale caused by A. brassicicola and A. brassicae.

並列關鍵字

Alternaria brassicicola ； A. brassicae ； nitrogen element ； mineral elements