黄瓜种子及其萌发期的化感作用研究

Allelopathy of Cucumber Seed during Germination

以大白菜、萝卜、番茄和黄瓜种子为受体,采用实验室培养皿种子发芽生物测试法研究了黄瓜种子浸提液、种子萌发、胚根和芽苗分泌物、芽苗腐解物和芽苗浸提液的化感效应。结果表明:(1)黄瓜种子浸提液对大白菜、萝卜、番茄和黄瓜种子萌发均有化感抑制作用,即黄瓜种子内含有某些化感抑制物质。(2)在水浸提过的黄瓜种子萌发过程中,它不仅对其近邻套种的大白菜、萝卜和番茄种子萌发产生化感抑制作用,而且其胚根和芽苗分泌物对后茬播种的4种蔬菜种子发芽也表现出不同程度的化感抑制作用;黄瓜芽苗腐解物和芽苗水浸提液也对各受体蔬菜种子发芽与生长产生不同程度的化感抑制作用,且随着腐解芽苗量的增加或浸提液浓度的升高,各受体蔬菜种子的发芽指标值、化感效应指数值和综合效应值随之降低。(3)黄瓜种子浸提液及芽苗各器官的化感物质对黄瓜种子的萌发与生长产生了自毒作用,且黄瓜芽苗腐解物、芽苗浸提液、胚根及芽苗分泌物对受体黄瓜的自毒作用均为最大。研究发现,黄瓜种子浸提液、种子萌发时期以及芽苗各器官的化感物质主要是通过抑制受体胚根的生长而起化感抑制作用,即受体蔬菜种子胚根对化感效应最为敏感;因黄瓜种子及萌发期释放化感物质的途径有所不同,导致受体大白菜、萝卜、黄瓜和番茄的化感响应也不相同;在黄瓜种子萌发和芽苗生长的早期,化感物质即开始在芽苗体内进行合成与积累,一部分可通过胚根和芽苗分泌途径释放到环境中,另一部分可通过芽苗腐解途径释放化感物质,并对受体蔬菜种子萌发与生长表现出较强的化感抑制作用。

In order to ascertain the allelopathy activity of cucumber seeds during germination,we studied the allelopathy effects of cucumber seeds aqueous extract, cucumber seed germination, cucumber radicle exudates,cucumber bud exudates, decomposed cucumber seedlings and seedling aqueous extract by adopting laboratory petri dish seed germination bioassay,using 4 categories of vegetables as receptors. The results indicated that： （1）The cucumber seed aqueous extract had an inhibitory effect on germination of Chinese cabbage,radish, tomato and cucumber seeds which showed the cucumber seed contained a few allelochemicals. （2）After extracted seed interior allelochemicals, the cucumber seed germination had allelopathy inhibitory effect on interplanted Chinese cabbage,radish and tomato seeds germination,and the cucumber radicle and bud exudates had different extent allelopathy inhibitory effect on after cultured Chinese cabbage, radish, tomato and cucumber seeds germination. The germination and growth of all vegetable receptors were inhibited to different extent with the different weight decomposed cucumber seedlings and different concentration seedling aqueous extract. It showed the concentration effect which was germination indexes, response index（RI） and synthesis effect （SE） value of vegetable receptors could decrease along with increasing of the weight of decomposed cucumber seedlings and the concentration of seedling aqueous extract. （3）The exper- iment of cucumber as receptor showed the allelochemicals of cucumber seeds aqueous extract and cucumber seedling organs had the autotoxicity on cucumber seed germination and growth,in which the autotoxicity of decomposed cucumber seedlings, seedling aqueous extract, cucumber radicle exudates and cucumber bud exudates were maximum. The studies suggested that allelochemicals of cucumber seeds aqueous extract,germination periods and seedling organs main inhibited the radicle growth,i, e. the radicle of vegetable receptors was most sensitive to allelopathy. Because release allelochemicals ways were different during cucumber seed germination,and the allelopathy response of Chinese cabbage,radish, tomato and cucumber were different. This experiment indicated during the early of cucumber germination and seedling growth,the allelochemicals began to compose and accumulate which released to environment by the radicle and the seedling and by seedling decomposition, then inhibited the germination and growth of receptor vegetable seeds.