杜仲形成层休眠机理

对杜仲(Eucommia ulmoides Oliv.)一年生枝条休眠中的芽和维管形成层的结构和蛋白质含量进行了研究,探讨了杜仲不同休眠期转化的生理生化机理.结果证实了杜仲树的休眠期包括2个被动休眠期和一个生理休眠期.在生理休眠期,无论用外源IAA处理,还是给予适当的温度和光照,形成层都不能恢复活动.而且,雌株进入各个休眠阶段的时间都比雄株早.树皮中的蛋白质含量在第一被动休眠期间(Q1)显著地逐步增高(P<0.01),进入生理休眠期(R)后,急剧降低,但第二被动休眠期(Q2)开始后又显著升高(P<0.01).杜仲雌雄株树皮中的蛋白质含量变化趋势基本一致,但雄株发生变化的时间比雌株早.SDS-PAGE电泳结果表明,在Q1-R-Q2的转变期出现一11.8 kD的特异蛋白条带.此特异蛋白条带可能与形成层休眠期中各阶段的转变调节有关.     

杜仲剥皮再生过程中可溶性蛋白和过氧化物酶含量及分布的变化

过氧化物酶在植物的损伤愈合中起着重要作用.我们采用生物化学分析和组织定位技术,确定了杜仲(Eucommia ulmoides Oliv.)剥皮再生过程中形成层区域过氧化物酶的分布和活性变化.剥皮后第4天至第21天,剥皮植株过氧化物酶含量大幅度增加(与对照比,增加了30～40倍),在整个剥皮再生过程中(从第0天至第63天),过氧化物酶在细胞分裂活跃的形成层和木栓形成层细胞中分布较少.而在愈伤组织、类皮层、成熟韧皮部和成熟木质部中分布较多.过氧化物酶在形成层及其两侧呈梯度分布,形成层中最少,在两侧的韧皮部和木质部中依次递增.其等电聚焦电泳显示两条酶带:POD Ⅰ和PODⅡ.前者只在木质部中分布,可能与木质部的分化有关;后者只在再生的组织中分布,可能与树皮再生过程有关.     

杜仲次生木质部细胞分化和脱分化过程中ATPase的超微细胞化学定位

The ultracytochemical localization of ATPase in the secondary xylem cells during their differentiation and dedifferentiation in the girdled Eucommia ulmoides Oliv. was carried out using a lead phosphate precipitation technique. Throughout the differentiation, which is a typical programmed cell death (PCD) process, ATPase deposits increased in the nucleus but decreased and progressively disappeared in the cell organelles. At the same time, the distribution of ATPase increased in the inner face of the cell wall and pits with cytoplasmic degeneration. The results demonstrated that the PCD was an energy dependent active process and was controlled by nuclear genes. On the other hand, the distribution of ATPase in the intercellular spaces increased with the formation of the new cambium resulted from the dedifferentiation of the secondary xylem cells after girdling. However, ATPase was not found in the nucleus of the dividing cells, suggesting that nutrients were transported through protoplast during differentiation, and through both protoplast and apoplast during dedifferentiation. Thus, the energy required in cell division was provided mainly by intercellular spaces. These findings indicate that the dynamic distribution of ATPase reflected which cell component was actively taking part in the cell metabolism at various stages of the plant development, and its distribution was associated with the physiological state of the cell. Based on the characteristic distributions of ATPase, the critical stage of cell differentiation and the relationship between the critical stage and dedifferentiation were discussed.     

粗茎鳞毛蕨原叶体细胞有丝分裂过程中微管列阵的变化

粗茎鳞毛蕨原叶体细胞有丝分裂过程中微管列阵的变化 何群 尤瑞麟 姆旺戈     

杜仲剥皮再生过程中可溶性蛋白和过氧化物酶含量及分布的变化(英文)

Peroxidases are known to play important roles in plant wound healing. Biochemical analysisand histochemical localization techniques were used to assess changes and distribution of peroxidases inthe recovering bark after girdling in Eucommia ulmoides Oliv. Between 4 and 21 days after girdling (DAG),peroxidases activity in the girdled trees significantly increased by 30-40 times over that in ungirdled trees.During the whole bark recovery process (from 0 to 63 DAG), the peroxidase signal was not found in thetissue regions subjected to intense cell division activity (regenerating cambial zone and phellogen). However,high peroxidase activity was detected in the callus, cortex-like, mature phloem and xylem. Interestingly, itwas shown that, in maturing xylem and phloem cells, there was respectively an inward and outwardperoxidase activity gradient on both sides of the cambium zone. An isoelectric-focusing electrophoresis ofthe extracted protein displayed two isozyme bands of peroxidase: POD Ⅰ and POD Ⅱ. POD Ⅰ was onlydetected in the xylem fraction and could play a role in xylem differentiation. POD Ⅱ was only identified inthe recovering bark portion and could be more engaged in bark regeneration process. A relationshipbetween IAA and peroxidase is also discussed.     

粗茎鳞毛蕨原叶体细胞有丝分裂过程中微管列阵的变化

应用Steedman‘s wax切片法,间接免疫荧光标记技术和激光共聚焦扫描显微镜技术研究了粗茎鳞毛蕨（Dryopteris crassirhizoma Nakai)原叶体大液泡化细胞和分生组织细胞有丝分裂过程中微管列阵的变化。结果显示：应用高浓度的多聚甲醛（8%）可以很好地保持大液泡化细胞的结构和微管的抗原性。结果也显示Steedman‘s wax切片法和间接免疫荧光标记技术的优点;（1）避免在微管标记过程中酶解细胞壁;（2）在乙醇脱水过程中样品中叶绿素的自发荧光被减到最小;（3）能够详细观察到有丝分裂过程中微管骨架的变化。因此,这种方法可以被广泛用来调查简单植物体和复杂植物体中细胞的有丝分裂过程以及发育过程中微管骨架的变化。