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Studies were conducted on the effects of various kinds of teleost pituitary gonadotropins on the in vitro maturation of carp oocytes. It was ascertained that after 24 h of incubation with gonadotropins, the highest percentage of oocytes with the nucleus in the migrating or peripheral position, or of mature oocytes, was observed in the case of ciprinide gonadotropins.Centrifuged hypophysial homogenates of the pike, sea-trout and pike-perch displayed a considerably weaker activity. The results obtained are indicative of a specificity of teleost pituitary gonadotropins. 相似文献
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Sodium chloride is the most often used chemical to malt ice and snow on the roads and has negative effects on the roadside
environment. Searching for ways to improve the conditions for growth of trees and shrubs near the roads becomes an urgent
matter. One such method of improving growth conditions for plants under salinity might be to use organic matter (green waste
compost) and mycorrhizal fungi. This study studied the effect of application in soil different salts on several trees and
shrubs growth in growing media. Also, effect of green waste compost and arbuscular mycorrhiza (AM) added to the growing medium
was evaluated in terms of growth and K+, Ca+2, and Na+ uptake. The highest pH of the growing medium was noted when sodium carbonate was used. The pH ranged from 8.7 to 9.0 after
eight doses of sodium carbonate. The pH of the growing medium was also significantly higher regardless of whether or not green
waste compost or mycorrhizal fungi were used. The type of growing medium had a great effect on the growth of most of the trees,
but among shrubs the growing medium was only important for Cornus alba, Sambucus nigra, and Spiraea vanhouttei. Growth of all these plants was much better under salinity when green waste compost or green waste compost with AM fungi
was used. In all the cases, when salinity of the growing medium retarded growth of trees and shrubs, sodium chloride was the
compound that had the strongest growth retarding effect. Leaf ionic composition was significantly affected by salinity in
the growing medium, and in some cases also by micorhizal fungi. The type of growing medium had various effects on sodium uptake,
depending on species. In most cases, the addition of green waste compost to the growing medium caused a greater amount of
sodium in the leaves of tested plants. The use of mycorrhizal fungi had no effect on the uptake of sodium, compared to the
control plants (without AM fungi). 相似文献
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AbstractIn many northern regions frost hardiness of new cultivars of woody plants and perennials is fundamental for nursery production and the greenery industry. This study was conducted to determine the effect of calcium fertilization on frost resistance of Forsythia sp. cultivars. Plants were sprayed five times at four week intervals with calcium nitrate 1?g of (Ca(NO3)2). 100?ml H2O?1 per shrub. Shoots were frozen at three temperatures: –20, –25, and –30?°C. In all cases the chlorophyll content index in the leaves, and the calcium (Ca2+) content in leaves and stems of forsythia cultivars were significantly higher when calcium nitrate supplementation was provided. The Ca2+content in the roots was not affected. The freezing temperature had a great effect on the stem frost damage of tested forsythia cultivars. The greatest damage was observed after freezing at –30?°C. However, tissue damage of plants that were sprayed with calcium nitrate was considerably less evident, and cross sections of stems looked significantly better. At the lowest temperatures (–25 and –30?°C) a positive effect of calcium fertilization on lower electrolyte leakage was observed in all tested cultivars. Fertilization with finely ground calcium nitrate increased stem freezing tolerance of forsythia tested cultivars, especially new ones which have stems that are more susceptible to frost damage. 相似文献
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