集安市植物地理学研究   总被引：1，自引：1，他引：0  

张绪成  唐景银  陈明  毕元路  肖佩民  苏宏波  董传友  景立东  李德生  朱执海 《吉林林业科技》2002,31(3):1-6

根据集安市的地理位置及自然状况，将集安市划分为西北部低山森林植物资源亚区，中部中山森林植物资源亚区，东南部丘谷森林植物资源亚区，并依据三个亚区植物资源组成的不同，提出了开发利用的方向和措施。  相似文献   

Differences in food composition between territorial and aggregative juvenile crimson sea bream Evynnis japonica     

KOSAKU  YAMAOKA  MADOKA  SASAKI  TAKAYA  KUDOH  MASARU  KANDA 《Fisheries Science》2003,69(1):50-57

ABSTRACT:   Food composition, fork length and condition factor of juvenile crimson sea bream Evynnis japonica were examined for two behaviorally distinct types of fish inhabiting a nursery ground. Studies were carried out from March to September 1996 at Morode Cove, Ehime Prefecture, Japan. One type of fish is solitary and territorial and the other type is aggregative. The food compositions of the two types of fish were different. Solitary fish foraged mainly on Gammaridea and Caprellidea (benthic organisms), and Copepoda (planktonic organisms); while aggregative fish foraged mainly on Copepoda, Appendiculata and Cladocera (planktonic organisms). These findings suggest that when we study food composition of E. japonica , it is imperative to consider whether the samples used for the analyses are from solitary (territorial) fish. Solitary fish showed significantly greater fork length and condition factor than aggregative fish, suggesting that the former will have a greater fitness value than the latter.  相似文献   

Potassium budgets in grassland systems as affected by nitrogen and drainage     

M.A. Alfaro  S.C. Jarvis  P.J. Gregory 《Soil Use and Management》2003,19(2):89-95

Abstract. The main inputs, outputs and transfers of potassium (K) in soils and swards under typical south west England conditions were determined during 1999/00 and 2000/01 to establish soil and field gate K budgets under different fertilizer nitrogen (N) (0 and 280 kg ha⁻¹ yr⁻¹) and drainage (undrained and drained) treatments. Plots receiving fertilizer N also received farmyard manure (FYM). Potassium soil budgets ranged, on average for the two years, from −5 (+N, drained) to +9 (no N and undrained) kg K ha⁻¹ yr⁻¹ and field gate budgets from +23 (+N, drained) to +89 (+N, undrained). The main inputs and outputs to the soil K budgets were fertilizer application (65%) and plant uptake (93%). Animals had a minor effect on K export but a major impact on K recycling. Nitrogen fertilizer application and drainage increased K uptake by the grass and, with it, the efficiency of K used. It also depleted easily available soil K, which could be associated with smaller K losses by leaching.  相似文献   

泥炭养分测定方法探讨   总被引：1，自引：1，他引：0  

王劲松  赵学兰 《山西农业科学》2003,31(4):44-46

在农业领域,泥炭作为生长介质的主要组成成分之一,被广泛应用于大规模花卉生产。文章仅对我国泥炭的氮、磷、钾、钙、镁的全量养分测定方法做一简单介绍,并且测定分析了我国北方泥炭丰富的营养元素含量及其形成原因。  相似文献   

苋菜类囊体膜组成的分子特性     

张修清 《西南大学学报(自然科学版)》1990,12(4):367-370

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Effects of Root-Zone Temperature on Growth and Development of Roots of Two Potato (Solanum tuberosum L.) Clones as Influenced by Plant Age, Nutrient Supply, and Light Intensity     

B. Sattelmacher  H. Marschner 《Journal of Agronomy and Crop Science》1990,165(2-3):190-197

The effects of supraoptimal root-zone temperature (30 °C) on growth and development of roots were investigated in water and soil culture with cuttings of two potato clones DTO-2 (heat tolerant) and LT-1 (heat sensitive) at different plant ages, with different compositions of the nutrient solution, and different light intensities. It is suggested that the negative relation between cutting age and heat susceptibility observed in our experiments, is a reflection of the decreasing shoot/root dry weight ratio rather than of age. Heat damage of root systems increased with the concentration of the nutrient solution, nitrate being the main factor responsible. The influence of light intensity on temperature mediated restriction of root growth was relatively small. However the roots of plants grown under low light intensity (60 W m⁻² PAR) appeared to be less stressed by supraoptimal temperature, i.e. roots appeared brighter, thinner and more ramified than plants growing at high light intensity (190 W m⁻²).  相似文献   

磷素营养对星星草幼苗抗碱性的影响   总被引：2，自引：0，他引：2  

孙国荣  李敬兰 《草业科学》1995,12(1):17-19

通过以不同水平磷素营养培养星星草幼苗，研究磷素营养对星星草幼苗抗碱性的影响，试验结果表明：在２．０％Ｎａ２ＣＯ２胁迫下星星草苗磷素营养的最适浓度为２．８ｍｍｏｌ·Ｌ＾－１ＫＨ２ＰＯ４，此条件下仅对株高，干重和鲜重的增长有促进作用，而且受害程度最小，对Ｎａ２ＣＯ３胁迫的缓解作用最强，在一定程度上可提高星星草幼苗对Ｎａ２ＣＯ３胁迫的抗性。  相似文献   

Influence of Biopost and Organo upon Flue-cured Tobacco Grown on Semigley. II. Chemical Composition of Tobacco Leaf and Changes in the Chemical Soil Complex     

A. BUTORAC  M. MESI&#;  J. BUTORAC  I. TUR&#;I&#;  F. BA&#;I&#;  N. VULETI&#;  M. BERDIN 《Journal of Agronomy and Crop Science》1995,175(5):307-316

The paper deals with the results achieved in investigating the effects of biopost and organo, in comparison with stable manure and mineral fertilization as well as one with the other, on the chemical composition of flue-cured tobacco leaf and on the changes in the chemical soil complex. Investigations were carried out on semigley in the central Drava Valley in Northern Croatia. While biopost is an organic fertilizer, organo is defined as an organic-mineral fertilizer since, in addition to an organic component, it also contains a mineral component. Both fertilizers affected the chemical composition of tobacco leaf, though they were applied in relatively small quantities. This was primarily reflected in a reduction of nicotine content and an increase in the content of reducing sugars in comparison with mineral fertilizing, though not always proportional to the rate applied. Here, biopost showed a certain advantage over organo.
The calcium content in tobacco leaf does not indicate any marked influence of the fertilizing treatments tested in the trial. Existence of such a relation seems more likely in the case of magnesium, while in the case of potassium, fertilizing with this bioelement had the crucial role with regard to its content in tobacco leaf.
As regards the changes in the chemical soil complex, the effect of the tested fertilizers, depending on the parameters studied, was either non-existent or very slight.  相似文献   

菊粉的原生素作用研究进展   总被引：8，自引：0，他引：8  

张名涛  顾宪红  杨琳 《动物营养学报》2003,15(4):12-18

本文综述了菊粉的原生素作用及机理 ,主要包括菊粉的微生物发酵、营养、免疫和抗癌作用等。  相似文献   

蜂胶化学成分的最新研究进展   总被引：8，自引：0，他引：8  

胡福良  玄红专 《养蜂科技》2003,(1):27-31,37

近年来蜂胶的化学成分，尤其是来自热带地区的蜂胶化学成分已成为国外蜂胶研究的热点。蜂胶的化学成分主要包括黄酮类化合物，芳香酸与芳香酸酯、醛与酮类化合物、脂肪酸与脂肪酸脂、萜类化合物、甾体化合物、氮基酸、糖类化合物、烃类化合物、醇和酚类及其它化合物。本文综述了近年来国外蜂胶化学成分的最新研究进展。  相似文献