排序方式： 共有3条查询结果，搜索用时 78 毫秒
1
1.
Nitrogen release patterns from seven leguminous trees were determined from 8-week laboratory incubations. The quantities
of extractable NH4
+-N and NO3
– released to the soil to which the leaves had been applied was determined at weekly intervals and was related to the initial
N, polyphenol, and lignin concentration of the leaves. Cumulative N mineralized was not correlated to initial N, soluble polyphenol
and insoluble tannin concentrations, but was correlated to lignin and neutral detergent fibre N (NDF-N) concentrations. The
ratios of NDF-N : N (r=0.68 at P<0.05), soluble polyphenol : N (r=0.70 at P<0.05) and (lignin+polyphenol) : N (r=0.75 at P<0.05) were negatively correlated with N release. Total polyphenol content was not a useful predictor of N release, but the
reactivity of the polyphenols as measured by their protein-binding capacity can be a useful predictor. In addition to measuring
the concentration of polyphenols, their reactivity with proteins must be measured, in order to assess their role in regulating
N release. The (lignin+polyphenol) : N ratio could be used to screen leguminous tree leaves for their potential to release
N in short-term experiments. This would allow for rapid screening of a large number of trees without detailed and expensive
field experimentation.
Received: 30 June 1997 相似文献
2.
对磺胺嘧啶与10只健康成年母鸡混合血浆蛋白结合的研究发现,虽然药物的结合浓度和游离浓度都与血浆中药物的总浓度正相关。但游离药物的增长速度和增加数量比结合药物的要大,因而蛋白结合率随着血浆中药物总浓度的增加而降低;按Scatchard法计算的K_A和n值分别为8.34×10~3M~(-1)和0.8。结果说明,磺胺嘧啶与母鸡血浆蛋白的结合能力较弱且容易饱和。在1.25×10~(-4)—6.21×10~(-4)M浓度范围内,药物的平均结合率为33.69±10.37%。该值与它种动物的结果有明显的差异。文章就此种种属差异进行了讨论。 相似文献
3.
Trees in farming systems can improve fertility of soils through mineralization of N in their litter. This study was to determine
the quality parameters (i.e., chemical composition) of organic residues that are associated with N mineralization in soils
under submerged and aerobic conditions, and to demonstrate that aeration conditions should be taken into account in categorization
of organic residues as N sources in farming systems. Incubation experiments were conducted in Aeric Paleaquult soil under
submerged and Oxic Paleustult soil under aerobic conditions. Treatments included litter and some fresh materials from trees
as well as rice straw available in farming systems of Northeast Thailand. S. grandiflora and L. leucocephala (32 g kg−1 N) had the highest net N mineralization in both conditions. Some lower-quality (< 20 g kg−1 N) residues did exhibit low net N mineralization during the 16-week period under submerged conditions, but displayed almost
no net N mineralization in aerobic conditions. Under submerged conditions, their net N mineralization was higher and more
rapid. The nitrogen content of the residues was the most important factor controlling N mineralization under both conditions.
Polyphenols exerted the highest negative influence on N mineralization in aerobic conditions, but exhibited no negative effect
in submerged conditions. In categorizing organic residues for their effective use in soil fertility management, soil aeration
conditions, as well as other environmental factors, should be taken into consideration in addition to residue quality. 相似文献
1