Phytoremediation potential of moso bamboo (Phyllostachys pubescens) for zinc and ultrastructure changes under zinc toxicity
This study has investigated toxicity of Zn and phytoremediation ability in shoot of moso bamboo. In hydroponic experiment the plants showed high Zn torelence up to application of 400 µM, while there was a general trend of decline in the roots and shoot biomass. Maximum concentration of 1594 mg kg–1 was observed in shoot after treating with 100 µM Zn. The shoot/root ratio reached the level of 0.27 under 10 µM zinc stress. Transmission electron microscopy revealed that electron-dense granules in vacuoles and structure of leaf cells were significantly effected by 200 µM of Zn. However, mitochondria and thylakoid membrane arrangement did not alter. Using scanning electron microscopy, Zn-related changes in the structure of the stoma were uncovered and crystal particles probably of Zinc were observed in stem.
Effect of sucrose on physiological and biochemical changes of proliferated shoots of Bambusa vulgaris Schrad. Ex Wendl in temporary immersion
Tissue culture systems have contributed to the massive propagation of bamboos. However, micro-propagated plants show a low percentage of rooting and ex vitro survival due to anatomical and physiological anomalies induced by in vitro factors. This study aims to determine the effect of sucrose on physiological and biochemical changes in Bambusa vulgaris Schrad. Ex Wendl shoots cultured in a temporary immersion system and in plantlets growing under greenhouse conditions. For this purpose, two concentrations of sucrose (20 and 30 g L−1) and a control treatment (sucrose-free medium) were used in a rooting culture medium. Our data revealed that the absence of sucrose in the culture medium improved the morpho-physiological, biochemical and anatomical development of the shoots. However, a high sucrose concentration decreased the total chlorophyll content and leaf area in shoots. Additionally, the hydrogen peroxide content and malondialdehyde increased in shoots cultured with 30 g L−1 of sucrose. On the other hand, scanning electron microscopy revealed that leaves of shoots which grow on medium containing 30 g L−1 sucrose displayed anatomical changes in the stomata of plants, whereas those from sucrose-free medium exhibited normal structural development. Finally, shoots cultured without sucrose showed a high survival rate and allowed a better adaptation of plantlets in the greenhouse. The temporary immersion systems combined with culture medium without sucrose offer new prospects for improving the physiology and biochemistry of plantlets during in vitro to ex vitro transition.
Die Populationsdynamik Von Canthocampt Us Staphylinus (Jurine) (Copepoda, Harpacticoida) Im Litoral Des Bodensees
The population dynamics of Canthocamptus staphylinus in the littoral zone of Lake Constance are described (fig. 2). Adult animals aestivate as cysts. The main part of the population emerges from the cysts in autumn. During the resting stage and the first spell after emerging, mortality is very low (fig. 3). Reproduction, expressed as numbers of ovigerous females, begins in November and reaches its maximum in January. The new generation becomes adult in May/June and encysts without previous reproduction. According to Sarvala (1979) it may be possible, that in littoral populations dormancy is induced by long day periods and temperatures of over 12° C (figs. 1, 2). In the profundal zone C. staphylinus also forms cysts, however, both light and temperature are not likely to induce this stage in depths of over 60 m.