土壤添加S-H混合物對青枯病菌之抑制效果及其無機態氮產物與抑菌性之關係

Suppression of the bacterial wilt pathogen, Pseudomonas solanacearum, in soil by amendment and relation of its nitrogen products to suppressive effects

周俊吉(C. C. Chou) ； 徐世典(S. T. Hsu) ； 曾國欽(K. C. Tzeng)

《植物病理學會刊》 4卷4期 (1995/12) Pp. 163-172

https://doi.org/10.6649/PPB.199512_4(4).0003

摘要

S-H混合物在六種不同供試土壤中對青枯病菌的抑制效果有很大之差異，四種土壤添加0.5-1.0%S-H混合物時，能迅速降低青枯病菌的數目，但另外二種土壤添加後，青枯病菌僅緩慢減少；後兩者之土壞須提高S-H混合物之添加量至1.5或2.0%時方能使青枯病菌快速減少。種植前七天，添加0.5及0.75%S-H混合物於不同供試土壤，其中具有抑茵性者均可有效防治番茄青枯病，但不具抑茵性者則否。此外，0.75%添加軍在某些土壤中可能傷害番茄幼苗之生長。S-H混合物(1%)加入土壤後，銨態氮的含量逐漸升高，到第5天達最高峰，隨後遞減；亞硝酸態氮自則在第6天才開始逐漸增加，隨後即快速增加：而青枯病菌之數目是在銨態氮達高量時緩慢下降，但在亞硝酸態氮快速上升時則迅速降低。施用N-serve (硝化作用抑制劑)於含S-H混合物之土壤，其銨態氮含量及pH值均提高，而亞硝酸態氮之形成則被抑制，但合S-H混合物之土壤.不論是否施用N-serve，都能降低青枯病菌的數目。添加S-H混合物之土壤中能偵測到對青枯病菌具有抑制作用之揮發性物質。以不同型態的無機氮替換S-H混合物中的尿素施用於土壤中，僅亞硝酸鈉替代者能快速減少青枯病菌的數目。單獨以氯化銨、亞硝酸鈉或硝酸納加入土壤中，僅添加亞硝酸鈉者具有降低青結病菌數目之能力。上述之結果推測，S-H混合物添加入土壤後，銨態氮漸累積，且因土壤pH值提高呈鹼性，可使其轉換成揮發性氨，因而造成初期青枯病茵的減少，但隨後亞硝酸態氮之上升到則為青枯病菌迅速減少的一種主要因子。

關鍵字

S-H混合物 ； 青枯病菌 ； 土機無機態氮

並列摘要

Six tested soil amended with S-H mixture differed in their ability to suppress Pseudomonas solanacearum Ps 95. The population density of P. solanacearum reduced rapidly in four soils amended with 0.5- 1.0% (w/ w) of S-H mixture. but reduced slowly in other two soils. For the latter soil, amendment with higher amounts (1.5- 2.0%) of the mixture was required to achieve a rapid reduction of the bacterial population. Amendment with 0.5% or 0.75% S-H mixture 7 days prior to planting was effective in controlling bacterial wilt of tomato in those amended soils that became suppressive to P. solanacearum, but was not effective in amended soils that were not suppressive to the bacterium. In certain soil, amendment with 0.75% S-H mixture may be toxic to tomato the seedling Upon addition of 1% S-H mixture. the soil pH and concentration of NH_4^+ -N increased rapidly, reached a peak at 5th day, and then decreased; the concentration of NO_2^- -N began to appear only after 6 days and thereafter increased rapidly. Initially slow reduction of P. solanacearum population in the amended soil was observed at the time when NH_4^+ - N remained at high concentrations; but subsequently rapid reduction of the bacterium occurred at the time when the concentration of NH_4^+ - N began to decrease and the concentration of NO_2^- -N started a rapid increase. Addition of N-serve (nitrapyrine), a nitrification inhibitor. to the S-H mixture-amended soil increased the concentration of NH_4^+ - N and soil pH, but decreased the formation of NO_2^- - N However, population decline of P. solanacearum in the amended soil was not affected by the addition of N-serve. Volatile substance(s) inhibitory to P. solamlcearum was detectable from the amended soil. When urea in the components of S-H mixture was substituted by different nitrogen form＂only the soil amended with that substituted by NaNO_2 was effective in suppression of P. solanacerum. Furthermore, when NH_4CI, NaNO_3 and NaNO_2, were applied individually to soils, only NaNO_2 reduced the population of P. solanacearum. The result suggested that the initial reduction of population of P. solanacerum in soil after amendment of S-H mixture was probably related to the accumulation of NH_4^+ - N, which may have been converted to volatile NH_3 because of the raised soil pH which was favorable for this conversion; whereas the followed rapid decline in the population was caused mainly by the rapid increase in nitrite.

並列關鍵字

S-H mixture ； Pseudomonaa solanacearum ； soil inorgnic nitrogens