Isolation of plant growth regulators fromPseudomonas amygdali

Summary Trans-zeatin and indole-3-acetic acid were isolated, as the main components of the cytokinin and indole mixtures respectively from culture filtrates ofPseudomonas amygdali, the causal agent of hyperplastic bacterial canker of almond.     

Bacterial phytotoxins: Mechanisms of action

Many species of phytopathogenic procaryotes produce toxins that appear to function in disease development. The affect the plant in different ways, the end result of which is the elicitation of chlorosis, necrosis, watersoaking, growth abnormalities or wilting. The most extensively studied toxins cause chlorosis. They specifically inhibit diverse enzymes, all critical to the plant cell. This inhibition results in a complex series of metabolic dysfunctions ultimately resulting in symptom expression. Substances causing growth abnormalities consist of known phytohormones and other compounds with plant hormone-like activities, but which have no structural relationship to the known hormones. The former act in the usual manner but, because of their elevated levels and imbalances, the host's regulatory mechanisms are overwhelmed and abnormal growth results (hyperplasia, shoot or root formation); the mechanisms of action of the latter group are unknown. High molecular weight, carbohydrate-containing substances, also acting in unknown ways, cause tissue watersoaking or wilting. Likewise, we know little about toxins causing necrosis except for syringomycin which affects ion transport across the plasmalemma.     

白纹竹芋的组织培养

本文报道了用组织培养技术繁效白纹竹芋,促进侧芽增生的方法,以白纹竹芋的根状茎为外植体,在MS培养基上诱导侧芽生长,再将新生芽转移至MS+BA6+NAA 0.5的培养基中进行继代培养,可获得大量不定芽并形成再生植株.培养过程中未发生愈伤组织,再生植株易于生根,幼苗种植成活率很高.     

两种腺嘌呤型衍生物的合成

为寻找更好的细胞分裂素——新的植物生长调节剂,以香叶醇为原料,在选定的有机溶剂中与三溴化磷反应得到香叶基溴;香叶基溴再与腺嘌呤反应,然后经过氧化铝柱层析分离,合成了两种国、内外文献资料未见报道的、新的化合物N6,N9-二香叶基腺嘌呤和N6,N6,N9-三香叶基腺嘌呤;并使用红外吸收光谱、核磁共振谱、质谱表征了这两种化合物的结构.此两种化合物的生物活性有待于进一步测试.     

激素对甘蔗心叶胚状体发生的影响

报道了2，4-D和细胞分裂素对甘蔗心叶胚状体的发生影响．从胚状体发生和发育进程以及过氧化物酶同工酶结果中发现，高浓度的2，4-D(3mg／L)有利于胚状发生，2，4-D和细胞分裂素的配合使用较单独利用2，4-D对胚状体发育过程中存在的心形期胚。     

细胞分裂素,氯丙嗪对葫芦藓发育过程的影响

用组织培养方法研究了细胞分裂素（６ＢＡ，ＫＴ）及调钙蛋白专一性抑制剂氯丙嗪对葫芦藓芽分化的影响．结果表明，细胞分裂素促进芽的形成，而氯丙嗪抑制受其诱导的芽的形成，芽分化过程中可能有调钙蛋白的参与，但激素处理下的芽大部分不能正常发育为配子体．