豆制品废渣发酵液对青菜种子萌发及植株生长的影响研究

枯草芽孢杆菌是一种广泛存在于土壤与根际的产酶细菌，在生物肥料领域具有广阔的应用前景．以豆制品废渣为唯一有机氮源进行液体发酵，测定了3株具有高活力的产蛋白酶枯草芽孢杆菌（BY25，NTI，NT2）的发酵液中氨基酸组成与浓度、蛋白质浓度、蛋白酶活力的差异．通过种子发芽和青菜盆栽实验，研究了发酵液对青菜种子萌发及植株生长的影响．发现实验组中BY25豆制品废渣发酵液能够显著促进青菜种子发芽与幼苗根系生长，培养96h后种子发芽率较添加去离子水处理的空白对照提高了13％，青菜幼苗平均根系长度较空白对照增加了66．3％；而以大豆粉为唯一有机氮源的BY25大豆粉发酵液对照组对青菜发芽和长根则产生显著抑制作用，同时BY25发酵液热灭活对照也无法表现出任何促进生长作用，说明发酵液中的蛋白酶等活性成分可能是影响种子萌发和幼苗生长的主要因子．添加BY25豆制品废渣发酵液培养40d后，盆栽青菜叶片SOD酶活力及根系活力均显著提高．

Effects of bean products waste fermentation extracts on germination and root growth of Brassica vat chinensis

Bacillus subtilis is a kind of gram-positive bacteria widespread from rhizosphere soil to gastrointestinal tract, which secreted different enzymes into culture media during stationary phase. Some of them have broad appli-cation prospects. In this study, three potent protease-producing 13. subitlis strains from different habitat were used to ferment with the only organic nitrogen source bean products waste residue. To set up a control group, the soy-bean powder was used as the only nitrogen source to ferment these strains, too. After fermentation, seed germina-tion, root elongation test and pot experiment were carried out with fermentation extracts addition, and it was ob-served that the bean products waste fermentation extracts from a soil originated B. subitlis BY25 could significantly improve the germination rate and root elongation of Brassica var chinensis, much better than two food originated B. subitlis. After 96 h of the seed culture, the germination rate improved 13% and the average root length increased 66.3% than the blank control group. When adding soybean fermentation extracts, the germination rate and root e-longation were significantly inhibited. Although similar amino acids content reserved, the heat-inactivated fermenta-tion extracts did not show any stimulating effect, which implied the major growth-promoting factors in the extracts mixture could not be amino acids, but other active elements such as proteases. After pot experiments, it was ob-served that the fermentation extracts from a soil originated B. subitlis BY25 could significantly improve the activities of SOD and root vitality of Brassica var chinensis.