Endogenous Factors Controlling Photoperiodism of Crop Plants.

作物植物（高等植物）的各种发育变化，如开花、结瘤和茎的终止生长，都受光周期的控制。短日照可以诱导马铃薯的块茎形成，也可以诱导大豆的茎终止生长。我们以前已经发现，马铃薯的结核是由短日照下在叶片中形成的结核酸及其糖苷诱导的。茉莉酸（Jasmonic acid， JA）与tuberonic acid有结构上的关系，对植物生长有多种抑制作用，如抑制幼苗生长。在大豆[Glycine max (L.)]的不确定和确定等值线中研究了JA可能参与终止大豆植株茎的生长。美林的简历。Harosoy]。在确定等值线茎生长终止前20天，两种等值线叶片中的ja样活性都很低。此后活动迅速增加，并在接近终止时达到最大值。虽然两种等值线叶片的活性波动方式相似，但确定等值线的活性远高于不确定等值线。通过高效液相色谱和质谱分离纯化，证实了JA的存在。在4个不同收获时间的样品中，叶片JA含量平均为0.18 mg/kg鲜重（近10^<-6> M）。外源施用茉莉酸浓度在10^<-7> M以上时，对培养的不定等值线茎尖有明显的抑制作用。在浓度10^<-6> M以上，有些芽根本不生长。这些结果表明，JA是控制大豆植株生长习性的主要内源因子。JA和TA的水平可能受光周期的控制。

Various developmental changes in crop plants (higher plants), such as flowering, tuberization and termination of stem growth, are under the control of photoperiods. Both tuberization in potato plants and termination of stem growth of soybean plants are induced by short days. We have previously found that potato tuberization is induced by tuberonic acid (TA) and its glucoside which seem to be formed in the leaves under the short days. Jasmonic acid (JA) which is structually related to tuberonic acid has various inhibitory effects on plant growth, for example, it inhibits the growth of seedlings. The possible involvement of JA in the termination of stem growth of soybean plants was examined in indeterminate and determinate isolines of soybean [Glycine max (L.) Merril cv. Harosoy].JA-like activities in leaves of both isolines were very low 20 days before the termination of stem growth of determinate isoline. The activity increased rapidly thereafter and reached a maximum near the time of the termination. Although the activities in leaves of both isolines fluctuated in a similar manner, the activity in the determinate isoline was much higher than that in the indeterminate isoline. The presence of JA in the leaves of the determinate isoline was confirmed by purification by high-performance liquid chromatography and by mass spectrometry. The level of JA in the leaves was 0.18 mg/kg fresh weight (nearly 10^<-6> M), on an average of four samples harvested different times. Exogenous application of JA to cultured shoot apices of the indeterminate isoline at concentrations above 10^<-7> M strongly inhibited growth. Above a concentration of 10^<-6> M, some shoots without any growth at all were observed. These results suggest that JA is a major endogenous factor that controls the growth habit of soybean plants. It is possible that the levels of JA and TA are under the control of photoperiod.