Sand burial is one of the main factors that affect seedling survival in sand land.Caragana intermedia is a psammophilous shrub and one of the commonly occurred species in fixed and semi-fixed sand dunes in the Otindag Sand Land and the Mu US Sand Land.In order to investigate the impacts of sand burial on seedling survival and growth of the species,seed-originated seedlings of Caragana intermedia grown in greenhouse for a month were buried by sand with four experimental treatments: T_C,control;T_1,one third ...

在沙地环境中,沙埋是影响植物幼苗存活的一个重要因素。中间锦鸡儿(C arag ana interm ed ia)是浑善达克沙地和毛乌素沙地固定和半固定沙丘上常见的一种沙生灌木。为了研究沙埋对其幼苗存活以及生长的影响,对出土后生长了1个月的中间锦鸡儿实生苗进行沙埋实验,实验处理:TC为对照,T1为沙埋幼苗地上部的1/3,T2为沙埋幼苗地上部的1/2,T3为沙埋到幼苗的近顶端。实验持续4周,每周收获1次。结果表明:TC、T1和T2没有幼苗死亡,T3有20%的幼苗死亡;沙埋对中间锦鸡儿幼苗的生物量、根冠比、根生物量比和茎生物量比有显著影响,叶片生物量比各处理没有显著差异,沙埋对幼苗的叶面积没有显著影响,在第1周T2和T3的小叶片面积显著大于TC,在其余3周,TC与T1、T2的小叶片面积没有显著差异,与全埋则有显著差异;沙埋对幼苗的相对生长速率(RGR)和净同化速率(N AR)产生显著影响,实验结束时,T3处理幼苗的RGR和N AR显著地小于其它3个处理。上述结果表明,部分沙埋(T1、T2)对沙生灌木中间锦鸡儿幼苗的生长发育没有显著的影响,而全部沙埋(T3)对其幼苗的生长发育产生显著的抑制,中间锦鸡儿是一个比较耐沙埋的物种。

 Haloaylon ammodendron, Artemisia desertorum, Nitraria tangutorum and Ephedra przewalskii are widely distributed in Minqin desert, which are the major forages in this area. In the present study, we examined the functions of wind prevention and sandfixing of these plants. We calculated the vertical section per crown and the vertical section per unit area. We also calculated the volume of sand fixed by each crown and the volume of sand fixed per unit area. Then the functions of wind prevention and sand fixing of these plants were compared. The results showed that the function of wind prevention of a single crown was decreased in the following order: N.tangutorum>H.ammodendron>A.desertorum>E.przewalskii. The function of sandfixing of a single crown was N.tangutorum>E.przewalskii. The functions of wind prevention and sandfixing per unit area were decreased in the following order: N.tangutorum>A.desertorum>H.ammodendron>E.przewalskii. If wind prevention is the main purpose, A.arenaria should be chosen. If sandfixing is focused, N.tangutorum should be chosen. If both of these functions are considered, N.tangutorum and A.desertorum will be a good choice.

梭梭(Haloxylon ammodendron)、沙蒿(Artemisia desertorum)、白刺(Nitraria tangutorum)和膜果麻黄(Ephedra przewalskii)是民勤荒漠区主要的牧草，分布面积较大。为了研究荒漠区牧草植物的防风固沙功能，在牧草利用的同时兼顾防风固沙功能。本研究用民勤荒漠区4种主要防风固沙植物样方调查资料，通过计算单株植物的纵断面积和单位面积上的纵断面积，以及单株植物的固沙沙堆体积和单位面积上的固沙沙堆体积，对4种主要植物群落的防风功能和固沙功能进行了对比分析。结果表明，单株（丛）的防风功能的排序为白刺＞梭梭＞沙蒿和膜果麻黄，单株（丛）的固沙功能白刺＞膜果麻黄，单位面积上防风功能的排序为沙蒿＞梭梭＞白刺＞膜果麻黄，单位面积上的固沙功能白刺＞膜果麻黄；单位面积上防风固沙功能的排序为白刺＞沙蒿＞梭梭＞膜果麻黄。如果只选择防风，则应选用沙蒿；如果侧重点是固沙，则应选用白刺；如果二者兼顾，则应选用白刺和沙蒿。

The reproductive characteristics of four plant species of the genus Nitraria L. in Ulan Buh Desert, Nitraria tangutorum Bobr., N. sibirica Pall., N. roborowskii Kom., N. sphaerocarpa Maxim., were studied. The reproductive allocation characteristics of reproductive tillers were studied based on measurements of the reproductive modules during blooming. The results showed significant quantitative differences exist in some reproductive modules of the four species, such as ramet height, reproductive tiller length, reproductive tiller diameter, number of flowers per tiller, dry weight of cymes, and dry weight of branches and leaves. Of the four plant species, N. sphaerocarpa was the smallest based on the above measured characters. N. sibirica allocated 44.51% of its mass to reproduction while the other three species allocated less than 20%. Statistical analyses were performed on the reproductive characteristics of four plant species. A significant linear correlation was found between reproductive tiller length and ramet height ( P N. tangutorum, N. sibirica, N. roborowskii, and N. sphaerocarpa , respectively. The statistical significant test level of the curve fitness was 0.0067, 0.0224, 0.0046 and 0.0006 for N. tangutorum, N. sibirica, N. roborowskii , and N. sphaerocarpa , respectively. Also, the cymous dry weight was significantly correlated to ramet height. Specifically the absolute biomass allocated to the reproductive organs from the total biomass of the reproductive tillers increased as ramet height increased. The correlation coefficients of the two indices for N. tangutorum , N. sibirica, N. roborowskii, N. sphaerocarpa were 0.9283, 0.6631, 0.8350, and 0.8324, respectively. The fitted curves of the two indices for N. tangutorum and N. roborowskii followed a linear relationship, whereas that of N. sibirica followed a power law, and that of N. sphaerocarpa was quadratic. Third, the reproductive allocation of the four plant species decreased as the biomass of the reproductive tillers increased which represented the size of the plant. The fitted curves of the two indices for N. sibirica and N. roborowskii were linear, and those for N. tangutorum and N. sphaerocarpa were inverse. Plant size had a significantly negative correlation with the reproductive allocation. The characteristics of the reproductive allocation of four plant species of genus Nitraria reflect their strategies for the resource utilization and the trade-off with the clonal propagation and ecological adaptation to the environment.

选定乌兰布和沙漠地区白刺属4种植物为研究对象,通过对其样株在花期的各生殖构件的数量特征及生物量调查,系统研究了唐古特白刺( Nitraria tangutorum Bobr.)、西伯利亚白刺( Nitraria sibirica Pall.)、大白刺( Nitraria roborowskii Kom.)和泡泡刺( Nitraria sphaerocarpa Maxim.)4种白刺属植物在生殖枝水平上的生殖分配。结果表明:不同白刺属植物在分株高度、生殖枝长、生殖枝基径、单枝花数、花序干重、枝叶干重等生殖构件的数量性状方面均有显著差异,其中泡泡刺的各生殖构件的数量均最小;除了西伯利亚白刺的生殖分配值达到44.51%外,其余3种白刺的生殖分配值均没有超过20%。经统计分析,4种白刺种群的生殖枝长分别与分株高度呈显著( P <0.05)的直线性正相关关系;生殖枝花序干重与分株高显著正相关;4种白刺的生殖分配随着分株生殖枝生物量的增加而减少,即白刺的个体大小与生殖分配之间呈现负相关关系。这种生殖分配特点反映了不同白刺植物对生长环境的资源利用、与克隆繁殖的权衡及对生态适应的策略。

Seed germination of 4 plant species from Zygophyllaceae including Nitraria sphaerocarpa, N. tangutorum, Peganum nigellastrum and Zygophyllum fabago were studied. After the seeds were separately treated with soil burial during winter (SB) and dry storage in laboratory (DSL) for 80 days, the germination rate was measured under 4 constant temperatures (10 ℃, 15 ℃, 20 ℃ and 25 ℃) and one fluctuating temperature regimes (25 ℃/5 ℃). The result showed that the seed germination rates of N. tangutorum, P. nigellastrum and Z. fabago were greatly influenced by temperature and the seed germination rates increased with the increasing temperature. The maximum germination rate of N. tangutorum seeds both in SB and DSL groups reached the highest values from 40% to 50% at 15 ℃ and 20 ℃. As for P. nigellastrum, it was closed to 0 % (SB) and 60% to 70% (DSL) at 5 ℃/25 ℃. And for Z. fabago, it was 90% to 100% (SB) and 60% (DSL) at 5 ℃/25 ℃. The seed germination rates of these three species were less than 10% at low temperature (10 ℃ or 15 ℃). The seed germination rate of N. sphaerocarpa was mainly affected by the storage methods and it was significantly higher in SB group than that in DSL group and the highest germination rate was from 60% to 70% in SB group atat 20 ℃ or 25 ℃.

对河西走廊泡果白刺Nitraria sphaerocarpa、唐古特白刺N. tangutorum、骆驼蒿Peganum nigellastrum和驼蹄瓣Zygophyllum fabago 4种蒺藜科植物的种子经过冬季土壤埋藏和室温贮藏各80 d后，在5种温度（10 ℃、15 ℃、20 ℃、25 ℃、5 ℃/ 25 ℃）条件下进行了萌发测试。结果表明，唐古特白刺、骆驼蒿和驼蹄瓣的种子萌发主要受温度的影响，萌发率随温度升高而增大；唐古特白刺种子经过冬季埋藏后，培养在15 ℃和20 ℃条件下达到最大萌发率（40%50%），而经室温贮藏后培养在25 ℃下有最高萌发率（40%50%）；骆驼蒿和驼蹄瓣种子经过冬季埋藏后，培养在5 ℃/25 ℃下达到最高萌发率（80%；90%100%），经室温贮藏后，同样培养在5 ℃/25 ℃下也达到最高萌发率（60%70%；60%）；在10 ℃条件下，3 种植物种子的萌发率不足10%。泡果白刺的种子萌发主要受贮藏方式的影响，埋藏后种子萌发率显著大于室温贮藏的种子，埋藏后的种子培养在20 ℃或25 ℃下达到最高萌发率（60%70%）。

Aims Our objective was to investigate the saline-alkali tolerance mechanism of Nitratia tangutorum to provide the basis for its use in saline areas in Heilongjiang Province of China and contribute to the theoretical understanding of urban tree species. Methods We treated seedlings of N. tangutorum to 20 kinds of mixed salt solutions with different salinities and alkalinities and examined saline-alkali stress on lipid peroxidation and enzyme activities. Important findings Injury to the plasma membrane of leaves increased with increasing salinity and alkalinity. Cell membrane permeability and electrolyte leakage of leaves were enhanced under salinity of 300 mmol·L –1 . The selectivity of plasma membrane permeability was damaged. The variation of malondialdehyde lipid peroxidation as plasmalemma peroxide product was consistent with that of electrolyte leakage, which showed a significant positive correlation ( r = 0.796). The activities of superoxide dismutase, peroxidase and catalase increased with both increased salinity and pH, which enhanced the ability of the active cell membrane system. Linear regression analysis showed that the significance order of four stress factors is salinity > pH > [HCO 3 – ] > [CO 3 2– ]. Nitratia tangutorum had a high tolerance to complex saline-alkali stress when the salinity was –1 and pH was < 10.59.

为研究白刺( Nitratia tangutorum )对盐碱生境的适应能力, 对二年生白刺实生苗进行了20组不同盐、碱浓度的胁迫处理。研究结果表明: 随着盐、碱浓度加大, 白刺叶片质膜所受伤害逐渐增加, 在300 mmol·L –1 盐浓度下, 白刺膜透性大幅度增加, 电解质大量外渗, 质膜的选择透过性遭到破坏; 丙二醛作为膜脂过氧化的产物, 它的变化规律与质膜透性的变化规律相一致, 两者呈极显著正相关( r = 0.796); 白刺叶片中的超氧化物歧化酶、过氧化物酶和过氧化氢酶活性随着盐胁迫浓度和pH的增加而有不同程度的升高, 增强了清除细胞内活性氧的能力, 对膜系统起到了一定的保护作用; 线性回归分析表明对白刺生长有重要影响的4个胁迫因素的重要性排序是盐浓度> pH > [HCO 3 – ] > [CO 3 2– ]。综合各项指标, 盐浓度在300 mmol·L –1 以下,pH小于10.59时, 白刺能够较好耐受, 具有较强的耐盐碱适应能力。

Abstract： In this study, the morphological indexes, biomass and Na+ and K+ contents of potted Nitraria tangutorum with Na compound fertilizer application were determined to investigate the effects of Na compound fertilizer on drought resistance of N. tangutorum. The results indicated that compared with control (no fertilizer) and diammonium phosphate, Na compound fertilizer improved significantly plant height by 109% and 45%, root length by 95% and 57%, main stem diameter by 88% and 43%, main root diameter by 85% and 22%, fresh weight by 236% and 68%, shoot Na+ content by 49% and 24%, and root Na+ content by 14% and 11%, respectively (P

摘要：采用盆栽育苗的方法，施用钠复合肥培育白刺（Nitraria tangutorum）植株，生长期结束测定其形态指标、生物量及Na+和K+含量，研究钠复合肥对白刺生长及其抗旱性的作用。结果表明，与对照和施(NH4)2HPO4相比，施钠复合肥培育的白刺株高分别增加了109%和45%；根长分别增加了95%和57%；主茎直径分别增加了83%和43%，主根直径增加了85%和22%；鲜质量分别增加了236%和68%；地上部中的Na+含量分别增加了49%和24%，根中的Na+含量分别增加了14%和11%。生长期结束后，盆中Na+施用量的22%被植株吸收，67%残留在盆中，可供来年植株吸收利用，淋失的Na+量占育苗前土壤Na+含量的6%。本研究表明，钠复合肥的施用能有效地促进白刺的生长并提高其抗旱性，且对土壤环境造成的影响较小。

Based on the principal component analysis, the cluster analysis and the membership function method, a pot experiment was conducted to evaluate quantitatively salt tolerance of the seedlings of Nitraria tangutorum, Nitraria sibirica, Zygophyllum xanthoxylon, Ammopiptanthus mongolicus, Caragana korshinskii, Reaumuria trigyna and Tamarix austromongolica growing in the Ulan Buh Desert by measuring many morphological and physiological indices. This study proposed that the ground diameter, stomatal conductance, water use efficiency, water potential, branch length, above dry weight, main root length, lateral root length, lateral root number and root diameter were considered as the important indicators of salttolerance evaluation for the hese desert shrubs. Seven shrubs were divided into strong, medium and weak salt tolerance, in which the R.trigyna and the T.austromongolica were strong, and the N.sibirica and N.tangutorum was medium, and the others were weak. The salt tolerance of seven desert shrubs was in order as R. trigyna>T.austromongolica>N.sibirica>N.tangutorum>A.mongolicus>Z.xanthoxylon>C.korshinskii.

针对乌兰布和沙漠地区生长的唐古特白刺（Nitraria tangutorum）、西伯利亚白刺（N.sibirica）、柠条（Caragana korshinskii）、长叶红砂（Reaumuria trigyna）、沙冬青（Ammopiptanthus mongolicus）、霸王（Zygophyllum xanthoxylon）、柽柳（Tamarix austromongolica）7种沙生灌木，通过盆栽试验的盐分梯度反复干旱法，在测定的一系列形态、生长指标以及光合、水分生理指标的基础上，经过主成分分析的降维分析，采用隶属函数对7种沙生灌木的耐盐性进行了聚类分析，在此基础上运用权重法定量评价了它们的耐盐性。结果表明，地径、气孔导度、水分利用效率、水势、枝条长度、地上干质量、主根系长度、侧根系长度、侧根数、根径可作为沙生灌木耐盐性评价鉴定的指标；7种植物的耐盐性分为强、中、弱三类：第Ⅰ类(强)植物，长叶红砂、柽柳；第Ⅱ类（中）植物，西伯利亚白刺、唐古特白刺；第Ⅲ类（弱）植物，沙冬青、霸王、柠条。同时7种植物的耐盐性由强到弱的顺序为长叶红砂、柽柳、西伯利亚白刺、唐古特白刺、沙冬青、霸王、柠条。

对唐古特白剌嫩枝扦插繁殖技术研究结果表明,应用激素处理唐古特白刺插穗,可大大提高嫩枝扦插的成活率.其最佳配比组合分别为ABT B2、IAA B1、GA B1、NAA B4、IBA B4,分别比对照提高了34.00%、27.33%、26.33%、25.66%、19.00%;对根系长度、新枝长度、叶片数和叶片长度增效最大的激素组合分别是IAAB1、NAAB2、IAAB1和NAAB2,增幅分别是对照区的1.41倍、2.20倍、1.53倍和1.40倍;对插穗生根增效作用最强的组合是IBAB2、B3、B4,其增幅高达2.32倍;激素与根数和成活率呈极显著正相关(P<0.01)和显著负相关(P<0.05),而与根长度、新生枝长度、叶片数量和叶片长度的关系不密切;浓度与各生长指标均无密切关系.

Variation in morphology and growth of seedlings of the climbing plant, Gynostemma pentaphyllum was examined in response to a light intensity gradient artificially created using plastic shade web. This revealed that G. pentaphyllum seedlings show a high level of plasticity in both morphology and growth in response to varying light environments: 1} relative growth rate, net assimilation rate, and total biomass decreased with decreasing light resource, while total leaf area, specific stem length, shoot height, branching angle, leaf area ratio, and specific leaf area increased with decreasing light; 2) relative growth rate declined with increasing plant size; 3) variation in light had no significant effects on biomass allocation. The increased specific stem length and shoot height observed across decreasing light intensities may enhance the likelihood that G. pentaphyllum seedlings will encounter external supports.

利用遮阳网产生光照强度梯度，以研究攀援植物绞股蓝(Gynostemma pentaphyllum)幼苗对光梯度的形态和生长反应。结果表明：1)相对生长速率、净同化速率和总生物量随光照强度减弱而降低，总叶面积、比茎长、株高、分枝角度、叶面积率和比叶面积却增加；2)株高生长与相对生长速率成负相关；3)幼苗生物量分配对光梯度的反应不敏感。这些结果意味着绞股蓝幼苗的形态和生长反应对不同光环境具有可塑性，比茎长和株高随光照减弱而增加有利于绞股蓝幼苗“寻找”到外界支持物。

The “grassland enclosure project” is an important measure to improve ecological and environmental quality of degradation grassland and promote economy sustainable development of pastoral area. In the present study, the Stipa purpurea community biomass allocation and carbon(C), nitrogen(N) and phosphorus (P) pools were investigated in three utilization management blocks including free grazing grassland (FG), four years enclosed grassland(F4) and eight years enclosed grassland (F8) on the northern Tibet Plateau alpine. The results showed that aboveground biomass of S. purpurea community in FG, F4 and F8 were 46.12, 146.40 and 256.44 g·m -2 , respectively. Root biomasses in layer of 0-15 cm were 274.74, 214.87 and 764.59 g·m -2 and root biomasses in layer of 15-30 cm were 17.80, 17.56 and 31.64 g·m -2 for these three treatments, respectively. These results suggested that enclosure significantly increased ( P <0.05) the community growth. S. purpurea and Carex moorcroftii had the highest biomass in F4 ( P <0.05). Enclosure significantly increased plant C, N and P pools of S. purpurea community and F8 had the highest nutrient pools ( P <0.05) among the three blocks. Our research provide basic data for revealing plant biomass and nutrient allocation response to grassland utilization management and evaluating ecological effects of “grassland enclosure project”.

草地围封工程是改善退化草原生态环境和促进牧区经济可持续发展的一项重大举措。以典型高寒草原紫花针茅( Stipa purpurea )群落为研究对象,选取自由放牧、围封4年和围封8年3块样地,比较分析不同草地管理方式下群落生物量分配和碳(C)、氮(N)、磷(P)储量差异。结果表明,自由放牧、围封4年和围封8年的群落地上生物量分别为46.12、146.40和256.44 g·m -2 ,0-15 cm土层根系生物量分别为274.74、214.87和764.59 g·m -2 ,15-30 cm土层根系生物量分别为17.80、17.56和31.64 g·m -2 ;围封显著促进了植被群落的增长( P< 0.05),其中对围封4年的优势种紫花针茅和青藏苔草( Carex moorcroftii )总生物量影响最显著( P <0.05)。围封显著提高了植物群落地上部分C、N、P储量,其中围封8年样地营养元素储量最高( P <0.05)。研究结果有助于揭示草地围封工程对藏北高寒草原紫花针茅群落物质分配的影响,为评估该区域退牧还草的生态效应提供了基础数据。

The relationships between grazing managements and soil carbon, nitrogen, phosphorus storage and their variations were studied in the degraded alkali-saline grassland by comparative study between fencing and grazing on time series. The results showed that aboveground biomass of degraded grassland decreased by 10.3%, 52.6% and 80.7% after 5, 6 and 8-years continuous grazing, respectively, however, the aboveground biomass of degraded grassland increased by 33.9%, 72.4% and 92.2% after 5, 6 and 8-years fencing, respectively. The underground biomass had similar response with aboveground biomass to grazing managements. Continuous grazing increased the soil pH and bulk density and reduced soil nutrient concentration whereas fencing reduced soil pH and bulk density and increased soil nutrient concentrations. With fencing, organic carbon and total phosphorus storage in surface layer soil gradually increased, however, total nitrogen storage firstly decrease and then increased. With grazing, soil carbon, nitrogen and phosphorus storage in surface layer soil all firstly increased and then decreased. After 5 years for fencing, the soil carbon, nitrogen and phosphorus storage was lower than grazing due to decreasing soil bulk density. The soil organic carbon significantly responded to aboveground biomass which suggested that the aboveground vegetation can be used as an effective indicator for soil carbon storage.

通过时间序列上围封和放牧的对比,研究了退化盐碱草地土壤碳、氮、磷储量及其变化与放牧管理的关系。结果表明,持续放牧5、6、8年后退化草地地上生物量分别降低了10.3%、52.6%和80.7%;而围封5、6、8年后地上退化草地地上生物量分别增加了33.9%、72.4%和92.2%;地下生物量对放牧管理的响应趋势与地上生物量相同。持续放牧增加了土壤pH和容重,降低了土壤养分浓度;围封对土壤pH、容重和土壤养分浓度的作用与放牧相反。围封后,表层土壤有机碳和总磷储量逐渐增加,总氮储量先降低后增加。然而放牧下,表层土壤碳、氮、磷储量均表现为先增加后降低。由于土壤容重的降低,封育5年后,围封地土壤碳、氮、磷储量要低于放牧地。土壤碳储量的变化对地上生物量的变化响应显著,因此,地上植被的变化能作为土壤碳储量有效的指示因子。

摘　要： 植物的内稳性与其在群落中的生态策略和适应性密切相关,然而从物种或功能群水平探讨内稳性与其竞争力关系的研究非常有限。本研究以青藏高原亚高寒草甸为例,通过N添加、P添加及N-P共添加的方式,选取4个功能群的10个物种,探讨养分添加下生物量变化规律及物种内稳性差异。结果显示,N添加及N-P共添加促进生物量的积累,而P添加抑制群落生物量的积累,说明该地区主要限制类型为N限制;N添加、P添加及N-P共添加均促进禾本科植物生物量的积累,而降低豆科及杂类草植物的生物量,其中仅N添加增加莎草科植物的生物量;P添加下,禾本科植物P内稳性强于其他物种,P内稳性可能在禾本科植物的竞争力上起到重要作用;其他处理及N、N∶P比未表现出一般性规律。因此,养分添加条件下,内稳性差异在高寒草甸物种竞争中可能并非主导因素。

By using the methods of experimental ecology and quantitative ecology, this paper studied the Nitraria tangutorum population characteristics under different sand burial depth at southeastern fringe of Tengger Desert, and analyzed the relationships between the population height, coverage, density, and biomass and the depth of sand burial.It was shown that under strong sand burial (at lacustrine basin lowland), the mean values of N.tangutorum population coverage, density, height, and biomass were higher than those under weak sand buried (at alluvial fan), but the coefficient of variation was in adverse. There existed significant correlations between sand burial and the population characteristics except the population density under weak sand burial. The optimum sand burial depth for the development of the population characteristics was higher under strong than under weak sand burial. Whether the sand burial was strong or weak, and whether the optimal sand burial depth was high or low, the development of the population characteristics was all restricted by the optimal sand burial depth. The increase of sand burial depth promoted the development of the population characteristics when the sand burial depth was lower than the optimal depth, but was in adverse when the depth was higher than the optimal. The responses of the population characteristics to sand burial depth were mainly manifested in the height growth and biomass. The development of population coverage and density was not only affected by sand burial, and more importantly, also affected by other factors, especially soil moisture.

运用实验生态学和数量生态学方法，研究了腾格里沙漠东南不同沙埋程度的白刺（ Nitraria tangutorum ）种群特征，并就各特征与沙埋深度的关系进行了分析。结果表明：强沙埋条件（湖盆低地）白刺种群特征均值都大于弱沙埋条件（山前冲积扇），但白刺种群各特征变异却是强沙埋条件小于弱沙埋条件；除弱沙埋条件白刺种群密度外，其他各性状都与沙埋有着显著相关关系；强沙埋条件的种群各性状发育最适沙埋深度均大于弱沙埋条件下；不论沙埋深度强弱和最适沙埋深度的高低，白刺种群各性状发育均受最适沙埋深度制约；低于最适沙埋深度，沙埋深度增加促进种群性状发育，高于最适沙埋深度，沙埋深度增加抑制种群性状发育。白刺种群各性状对沙埋深度的响应主要体现在高生长和生物量上；盖度和密度的发育不仅受沙埋的影响，更主要是受沙埋深度影响下的其他资源特别是水分的限制。

In order to understand the effects of sand burial on survival and photosynthesis of two Chenopodiaceae annuals ( Agriophyllum squarrosum and  Corispermum marocarpum ) growing in the Horqin Sand Land, and to compare their differences in abilities and photosynthetic physiological mechanisms to resist sand burial, the net photosynthetic rate, stomatal conductance, transpiration rate and water use efficiency of the two species were studied after they were buried at different sand depths for 5, 10, 15 days, and their survival rates were recorded at the end of the growing period. The results showed that, compared to  C. marocarpum ,  A. squarrosum  had a stronger ability to resist sand burial. Some of  A. squarrosum  seedlings survived after burial depth exceeded plant height by 10 cm, while no seedlings of C. marocarpum  survived after the burial depth reached 100% of its seedling height. With the increase in burial depth, the survival rates of both  A. squarrosum and  C. marocarpum  decreased; however, the survival rate of  C. marocarpum decreased to greater extents. Both species closed their stomata or decreased their openness, increased transpiration rate and water use efficiency as measures to adapt sand burial stress. Net photosynthetic rates of the two species decreased sharply with increased burial depth, indicating that sand burial was very harmful to the photosynthetic system of plants. Compared to  C. microphylla, A. squarrosum  adapted better to sand burial stress by recovering the net photosynthetic rate to a certain extent when the burial time increased.

为了解沙埋对沙生植物存活的影响及其光合生理响应特征，比较不同藜科沙生植物耐沙埋能力及其光合响应，在内蒙古科尔沁沙地研究了沙米（ Agriophyllum squarrosum ）和大果虫实( Corispermum marocarpum )在不同沙埋深度下第5、10、15天的净光合速率、气孔导度、蒸腾速率、水分利用效率的变化，并于植物生长末期对存活率进行了测定。结果表明：沙米较大果虫实具有较强的耐沙埋能力，其中沙米幼苗最大耐沙埋深度超过苗高10 cm，大果虫实在埋深等于其苗高时全部死亡；随沙埋深度增加，沙米和大果虫实的存活率均显著下降，但沙米的下降幅度明显小于大果虫实；沙埋后，2种植物的气孔关闭或开放程度减小，通过降低蒸腾速率和提高水分利用效率来适应沙埋胁迫；随着沙埋胁迫的加剧，2种植物的净光合速率下降，表明沙埋胁迫对植物的光合作用破坏较大；相比于大果虫实，沙米对于沙埋胁迫有着更好的光合适应，随着胁迫的时间增加，其净光合速率有所恢复。    

以内蒙古锡林河流域沿水分梯度分布的灰脉苔草(Carex appendiculata)、贝加尔针茅(Stipa baicalensis)、羊草(Leymus chinesis)、大针茅(stipa grandis)、小叶锦鸡儿(Caragana microphylla)和冷蒿(Artemisia frigida)6个草地群落为对象,研究了围封禁牧与放牧样地中144个共有植物种的高度、丛幅面积、茎、叶和株(丛)生物量、茎叶比等性状.结果表 明:1)在个体水平上,放牧样地中植物的生殖枝高度、营养枝高度、丛幅面积、单株(丛)生物量、茎、叶生物量和茎叶比均显著低于围封禁牧样地,植物在放牧 干扰下表现出明显的小型化现象;2)在群落水平上,放牧亦显著降低了群落总生物量和茎、叶生物量;3)过度放牧显著改变了物种的资源分配策略,使生物量向 叶的分配比例增加,向茎的分配比例减少.资源优先向同化器官分配可能是植物对长期放牧干扰的一种重要适应对策;4)轻度放牧对物种的资源分配没有显著影 响,单株(从)生物量和群落茎、叶及总生物量均表现出增加趋势,这与过度放牧的影响正好相反.过度放牧引起的植物个体小型化改变了生态系统中物种的资源分 配策略,进而对生态系统功能产生重要的影响.