The vegetative growth and mineral nutrient accumulation in Amorpha fruticosa.seedlings under different waterlogging stress conditions were studied.The result showed that roots under the surface submerge waterlogging treatments grew superficially,a mass of aquatic adventitious roots grew on the stems of semi-submerge waterlogging treatments,before the growing of aquatic adventitious roots,stems grew in advance to adapt to waterlogging stress.The absorption of N,P,Ca,Fe and Mg increased in the seedlings under three different waterlogging stress conditions,while the absorption of Cu decreased.The allocation of N,P,Ca,Zn and Cu was changed and had obvious change with the control group(P<0.05).The total accumulation of mineral nutrients in waterlogging treatments was not lower than normal level,and no deficiency symptoms were observed on the nutritive growth.The above results indicated that A.fruticosa had a strong waterlogging tolerance ability to adapt waterlogging stress by choosing effective energy saving ways.

The nutrient structure of Amorpha fruticosa was studied during the growing season by analysing the nutrient contents of leaves,stems and roots of different diameter for C,N,P,K,Ca,Mg,Fe,Mn,Cu,and Zn.1) The nutrient contents of N,P and K were the inverse of stem and root diameter(they reduced as the diameter increased).The highest contents were in the leaf,stem and thin roots.2) There was no specific pattern of Ca,Mg,Fe,Mn,Cu,and Zn contents with stem and root diameters.3) The correlation between trace elements was poorer than that between trace elements and macro-elements.Most correlation element pairs were in the stem,followed by the leaves,then roots.N,P,and K had the most relationships with other elements but C,Zn and Ca had fewer.4) There was more organic carbon,N,Ca,Mn and Cu in the leaves than in the stems and roots of A.fruticosa during the whole growingh season.The order of macro-element content in leaves was CNKCaMgP,and the order of trace element contents was FeMnZnCu.

17 morphological characteristic indexes and 11 nutritive elements of five different parts of Amorpha fruiticosa firstly planted in the Qinghai-Tibet Plateau（Lhasa,Maqu） were investigated to understand the response of phenotypic plasticity and plant resource allocation of Amorpha fruiticosa to alpine habitat.The results of this study showed that phenotypic differences of A.fruiticosa was found in the two investigation regions,especially,the root morphological indexes were greatly different.The biomass proportion and nutritive element concentrations of different parts of A.fruiticosa was different between Lhasa region and Maqu region,which was caused by the response of plant resource allocation to alpine habitat.The correlation relationship between morphological indexes and nutrient element concentrations of A.fruiticosa was complex among two regions.

The changes of growth and physiological characteristics of Amorpha fruticosa seedlings under different waterlogging stress conditions were studied by carrying out a water soaking treatment.The nutritive growth had no obvious change although a mass of aquatic adventitious roots and specialized lenticels grew in a short time to adapt to the different waterlogging stresses.Chlorophyll contents in leaves and photosynthetic rate decreased differently in different flooding treatments: the main factor in surface submergence and semi-submergence waterlogging was the reduction of stomal condunctance,while the main factor in the nearly submerged waterlogging was the increase of intercellular CO2 concentration.Root activity of the surface submerge waterlogging treatments decreased insignificantly,while it fell by 58% between in the semi-submerge waterlogging treatments and the control group,and 51% between the nearly submerge waterlogging treatments and the control.Soluble sugar and proline contents in waterlogging treatments were all more than that in the control while the semi-submerge waterlogging treatments had the highest contents of them with the quantity 22.43 mmol/L and 570 μg/g respectively,and had obvious change with the control group(P<0.05),while MDA content showed no change.A.fruticosa could adapt to waterlogging stress by the growth of many aquatic adventitious roots and specialized lenticels and by accumulating osmotic adjustment substances.A.fruticosa had strong waterlogging tolerance ability and could be planted in wet land.

Three native shrubs inhabiting in Maqu county, including Salix oritrepha, Amorpha fruticosa and Hippophae rhamnoides, were used as materials to investigate the differences of total P content, available P content and P fractions between rhizosphere and non-rhizosphere soils. It was found that there was a higher available P concentration in the rhizosphere soil comparing to that in the non-rhizosphere soils of A. fruticosa and S. oritrepha. The total P content in the rhizosphere soil was higher than that in the non rhizosphere soil of the three shrubs. The concentrations of total P and H20-P were lower in the non rhizo- sphere soil than that in the rhizosphere soil except H. rhamnoides. The contents of NaOH-Pi and NaOH- Po were higher in the rhizosphere soil than that in the non-rhizosphere soil of the three shrubs. The con- centration of HHCl Pi in the rhizosphere soil was lower than that in the non-rhizosphere soil except A. fruticosa. The concentration of HHCl-Po in the rhizosphere soil was higher than that in non-rhizosphere soil except S. oritrepha. Regression analysis indicated that there was a negative significant relationship be- tween available P concentration and pH in both soils of S. oritrepha and A. fruticosa, but no relationship was found between total P and available P concent in both of the rhizosphere and non-rhizosphere soils.

应用数量统计方法,对在西藏拉萨市、曲水县和甘肃玛曲县等青藏高原区首次种植的紫穗槐3个居群的17项形态特征指标进行比较分析.变异系数分析结果表明:不同居群内及居群间的形态特征存在一定程度的变异.采用主成分分析方法,找到了积累贡献率达86.603％的4个主成分,新枝长、新枝直径、老枝直径、主根直径、二级侧根总长5个性状是造成紫穗槐形态变异的主要因素,并分析了其与根际土壤生境的相关性.通过对紫穗槐一级侧根与二级侧根根长频率分布研究,表明:(1)不同居群内及居群间各个阶段根长存在差异;(2)居群3(玛曲)中一级侧根和二级侧根根长≥40 cm的频率明显高于另外两个居群.

The influences of nutritional quality on Amorpha fruticosa were studied using five simulated defoliation intensities(20%,40%,60%,80%,and 100% proportion of aboveground vegetation).The grey correlation degree method was used to comprehensively analyze seven nutritional indexes: crude ash(Ash),neutral detergent fiber(NDF),acid detergent fiber(ADF),water-soluble sugar(WSC),crude protein(CP),phosphorus(P),and potassium(K).When the defoliation intensity of A.fruticosa was 40%,the weighted grey correlation degree of leaves and stems was 0.781 2 and 0.651 3,respectively.This was larger than that of the other defoliation intensities.A.fruticosa had the best nutritional value with the 40% defoliation intensity treatment.

3 years old Amorpha fruticosa planed in experimental field was used to study the water content and its relationships with soil moisture in different growth stages. The results showed that average water con tents of stem and leaf（57.49% and 64. 10%）were much higher than soil moisture in different depths（5.31% , 5.59% and 5.28%）,so it had a strong water absorption and water holding capacity;the GW/DW ratio was high and GW/DW ratio was low, which suggested that Amorpha frulicosa was suitable for green fodder in early growth stage and hay making in late growth stage;the stem/leaf ratio increased monthly from 0.74 in early June to 1.71 in early September; there was a certain correlation among water content of stems, leaves anti whole plant,the GW/DW ratio and the stem/leaf ratio; both fresh and dry weight of stems anti leaves were increased with the growth period,dry matter of leaf and stem accumulated rapidly from July to August and July to Sep tember respectively; regression analysis indicated that stems, leaves and total aboveground biomass per plant showed a significant negative correlation with soil moisture in different depths.

Soils with different reclamation period were collected from Jiangzi Counties of Shigatse region and Qiongjie Counties of Shannan region in the Tibet Autonomous Region,China.Soil phosphorus forms with different reclamation periods and rangeland were analyzed by the method of Hedley revised by Tiessen.The results of this study showed that the inorganic phosphorus fractions ranked in the following order: Dil.HCl-PiConc.HCl-PiNaOH-PiNaHCO3-PiH2O-Pi.Inorganic phosphorus fractions increased with the land reclamation years,in which Dil.HCl-Pi and Conc.HCl-`Pi had maximum increase.The rangeland with a small inorganic phosphorus pool in the Qiongjie County had a bigger organic phosphorus bank than when compared to the farmland.Organic phosphorus fractionation decreased when reclamation period was below 50 years,whereas increased when reclamation period was over 50 years.