大豆提取液对超结瘤现象的抑制

SOYBEAN SEEDLING EXTRACTS INHIBIT SUPERNODULATION

将超结瘤大豆(Glycine max)突变体nts 382用一定数量的固氮菌接种后,这些植株上产生大大多于同样条件下生长的野生型亲本Bragg植株上所形成的根瘤。把nts 382幼苗地上部的抽提液加入培养基中,不能使Bragg的幼苗表现为超结瘤型,但若把Bragg幼苗抽提液加入nts 382培养基中,则超结瘤现象受到明显的限制。采用nts 382植株地上部做接穗嫁接到Bragg砧木上,这个嫁接体仍表现为超结瘤型,对换接穗和沾木位置后的嫁接体则表现为野生亲本型。Bragg抽提液对nts 382植株超结瘤的抑制性还随所用豆苗生长期延长而明显减弱,接种后60天的植株抽提液基本无效。未接种的Bragg豆苗抽提液不能抑制nts 382的超结瘤。与此相反的是在嫁接实验中不存在这个时间效应,无论用Bragg幼苗或较为成熟的植株做接穗,都能有效地抑制nts 382砧木上的超结瘤现象。

When soybean (Glycine max) nodulation mutant nts 382 was inoculated with Bradyrhizobium japonicum,these plants nodulated significantly more than the parental type Bragg.Nts 382 seedlings displayed wild-type nodulation pattern when aqueous extracts of young Bragg shoots were applied to the cultural medium together with nutrient solution. Application of young nts 382 shoot extracts to Bragg seedlings did not result in any apparent increase in nodule number.In graft experiments,young shoots from mutant nts 382 induced supernodulation on Bragg root stocks,while no supernodulation was observed when Bragg seedlings were used as scion and grafted onto nts 382 root stocks.Further,the effectiveness of Bragg plant extracts to suppress supernodulation on nts 382 seedlings was found to depend on the age of the plant material used,being very ineffective with extracts from 60- day-old plants.The age effect was not observed in graft experiments.These findings suggest that soybean supernodulation phenomenon may be controlled by one or a few unknown chemicals or plant hormones.