毛乌素沙地4种沙生植物种子萌发及出苗对沙埋及单次供水的响应

飞播固沙作为一项快速而有效的现代化治沙措施,已成为毛乌素沙地植被恢复与重建的重要手段。但此项技术仍存在一些问题,如飞播后成苗率较低等。以毛乌素沙地优势植物柠条（Caragana korshinskii）、羊柴（Hedysarum laeve）、油蒿（Artemisia ordosica）与籽蒿（Artemisia sphaerocephala）为研究对象,人工控制7个沙埋深度和9个水分梯度,研究4种植物种子萌发和幼苗出土对沙埋和单次供水的响应,阐明多大的单次降雨才能保证种子萌发与幼苗出土及出土幼苗的维持时间。结果表明,对于柠条和羊柴质量相对较大的种子而言．种子主要在供水量10．20mm,埋藏深度为0．5．2cm的条件下出苗,但在埋藏深度为5cm时这两个物种仍有少量种子能够出苗;而对于油蒿和籽蒿质量相对较小的种子而言,种子主要在供水量10．20mm,埋藏深度为0．5cm时出苗,当埋藏深度为1．5cm和2cm时不能顺利出苗。沙埋深度0．5cm条件下,4个物种具有最高的出苗率和出苗速率。在试验期内（30d）,柠条、羊柴和油蒿出土幼苗分别在单次供水量为5、7．5mm和7．5mm时全部死亡,在单次供水量高于15mm时4个种的出土幼苗死亡率大多低于50％,且随供水量的增加出土幼苗死亡率降低。结合毛乌素沙地降雨特点与本次实验结果,0．5cm的沙埋及7．5mm以上的单次降雨是上述4种植物自然条件下出苗较好的重要条件。     

Effects of watering regime and depth of burial on seedling emergence of four dominant psammophytes in the Mu Us sandy land, Inner Mongolia, China, and relevance to revegetation of a desertified region

Four dominant psammophyte species are air-seeded in attempts to revegetate the Mu Us sandy land in Inner Mongolia, but seedling emergence is low. This study sought to clarify the behaviour of seedling emergence under different water supply and sand burial regimes to improve the technology of air seeding. Seeds were buried in sand at depths of 0, 0.5, 1, 1.5, 2, 3 and 5 cm and supplied one time with 2.5, 5, 7.5, 10, 15, 20, 30 or 40 mm of water or with 2.5 mm once every 3 days for 30 days. Our study showed that a 0.5-cm burial depth and under 10- to 20-mm single-watering regimes resulted in highest seedling emergence percentage and rate of these four species. All emerged seedlings of Caragana korshinskii , Hedysarum laeve and Artemisia ordosica died under 2.5, 5 and 7.5 mm of watering, respectively, but seedling mortality was <50% when the single-watering regime was >10 mm. In the field, germination of the four species increased from the top of the dune to the middle of the leeward side and then to the bottom. Based on precipitation pattern in the Mu Us sandy land, our study indicates that 0.5-cm burial depth and a single-watering regime of >7.5 mm is the threshold condition for seedling emergence.     

鄂尔多斯高原4种主要沙生植物种子萌发与出苗对水分和沙埋的响应

 羊柴 (Hedysarum leave)、柠条 (Caragana korshinskii)、籽蒿 (Artemisia sphaerocephala)与油蒿 (Artemisia ordosica)为鄂尔多斯高原广泛分布的植物种,也是该地区飞播选用的主要植物种。由于飞播为鄂尔多斯高原植被恢复的重要手段,而飞播后植物种子的出苗率与土壤水分及沙埋密切相关。因此,上述植物种子萌发与出苗对水分和沙埋反应的研究对当地退化生态系统的恢复具有重要意义。通过温室控制实验,对4种植物萌发特性及出苗与水分和沙埋深度的关系进行研究,阐明了种子萌发最适合的水分条件和沙埋深度。结果表明,4种植物种子萌发与出苗最适宜的供水量都接近于当地种子萌发时期的平均降水量, 最适宜的沙埋深度为0.5～1 cm, 过多的水分和过深的沙埋会降低种子萌发与出苗,反映了4种植物对沙区环境的生态适应。4种植物最适宜的供水量均为123 ml,羊柴、柠条、籽蒿和油蒿的最适沙埋深度分别为：0.5、1.0、0.5和0.5 cm。根据实验结果及当地气候特点,鄂尔多斯地区的飞播时间应由6月初提前至5月中下旬,以提高飞播植物的出苗率。     

沙埋对六种沙生植物种子萌发和幼苗出土的影响

研究了沙埋对科尔沁沙地6种优势植物的种子萌发和幼苗出土的影响．进行0．2、4、6、8、10和12cm等7个深度沙埋处理．结果表明,在不同沙埋处理时,沙蓬萌发差异显著。而差不嘎蒿2锄埋深与其他埋深的发芽差异显著,其他4种植物0cm埋深与其他埋深的发芽差异显著;沙埋对所有植物幼苗出土均有显著影响,埋深增加,出苗率减小;繁殖体大的物种与繁殖体小的物种相比,能从更深沙层中出苗,幼苗出土最大深度排序为苦参>东北木蓼≥沙蓬>山竹子>雾冰藜>差不嘎蒿．     

沙埋与供水对毛乌素沙地两种重要沙生植物幼苗生长的影响

沙埋与水分是影响毛乌素沙地植物存活、生长的关键因子。通过沙埋与供水的野外控制实验,研究了毛乌素沙地重要物种柠条(Caragana korshinskii)与羊柴(Hedysarum laeve)幼苗存活及生长对沙埋和供水的反应。结果表明:适量的沙埋(0.25H-0.50H沙埋,H为苗高)与供水(柠条50mm/月,羊柴75mm/月)可以促进幼苗生长,过量的沙埋与供水则会抑制生长甚至导致幼苗死亡。柠条幼苗在50mm/月供水,0.25H、0.50H沙埋,羊柴幼苗在75mm/月供水,0.25H、0.50H沙埋下具有较高的相对生长速率和净同化速率;幼苗在1.0H和1.25H沙埋下全部死亡。供水量较小、沙埋较浅时,两种植物根冠比均较高;当供水量最大时,柠条幼苗根冠比在沙埋最深和没有沙埋时较大,而羊柴幼苗根冠比仍在没有沙埋时最高。     

沙埋对两种沙生植物幼苗生长的影响及其生理响应差异

为了解沙埋对沙生植物生长的影响及其生理响应特征, 比较不同沙生植物耐沙埋能力及其机制, 2010年在内蒙古科尔沁沙地研究了不同深度沙埋下沙蓬(Agriophyllum squarrosum)和盐蒿(Artemisia halodendron)幼苗的存活率、株高等生长特性及其渗透调节物质含量, 保护酶活性和膜透性的变化, 得到以下结果: 沙蓬和盐蒿幼苗均具有较强的耐沙埋能力, 其中沙蓬幼苗最大耐沙埋深度超过幼苗10 cm, 盐蒿幼苗最大耐沙埋深度超过其株高8 cm; 随着沙埋深度增加, 沙蓬和盐蒿幼苗的存活率和株高均显著下降, 沙蓬的下降幅度显著小于盐蒿; 沙埋处理下两种植物均未表现出受水分胁迫, 沙埋导致其光合面积下降, 幼苗顶土困难, 是影响其存活和高生长的主要生态机制; 随着沙埋深度增加, 沙蓬幼苗丙二醛(MDA)含量显著增加, 盐蒿幼苗MDA含量下降, 虽然二者膜透性均呈增加趋势, 但沙蓬膜透性增加幅度显著低于盐蒿, 说明细胞膜受损是导致二者幼苗存活率下降和生长受到抑制的主要生理机制, 沙蓬膜透性受损程度较低是其耐沙埋能力较强的主要生理机制; 沙埋胁迫下, 虽然两种植物都通过提高过氧化物酶活性和脯氨酸含量减轻细胞膜受损程度, 但沙蓬体内超氧化物歧化酶也表现出重要协调作用, 使之酶促系统在保护细胞膜免受胁迫损伤过程中的作用更有效。     

库布齐沙漠不同人工固沙灌木林土壤微生物量与土壤养分特征

在库布齐沙漠东段选取人工油蒿+杨柴半灌木混交林、人工柠条锦鸡儿灌木林和人工沙柳灌木林3种人工固沙灌木林为对象,以流动沙地为对照,研究了不同人工固沙灌木林土壤微生物生物量碳和氮、土壤微生物数量、土壤养分变化特征及其相互间的关系,并运用综合指数法对不同人工固沙灌木林的土壤恢复效果进行评价.结果表明: 与流动沙地相比,3种人工固沙灌木林土壤有机质、全氮、全磷、速效氮、速效磷含量均有不同程度的提高,表现为油蒿+杨柴林地＞柠条锦鸡儿林地＞沙柳林地,且均随土层加深而依次降低;3种人工固沙灌木林土壤微生物数量、微生物生物量碳和氮均较流动沙地有不同程度的提高,油蒿+杨柴林地土壤微生物生物量碳氮和细菌相对数量高于柠条锦鸡儿林地和沙柳林地,而真菌与放线菌相对数量则表现为柠条锦鸡儿林地＞沙柳林地＞油蒿+杨柴林地;影响3种人工固沙灌木林土壤细菌相对数量、微生物生物量碳和氮的因素是土壤有机质、全氮、全磷、速效氮、速效磷含量及C/N,而放线菌、真菌相对数量主要受土壤全磷、速效氮和速效磷含量的影响;不同人工固沙灌木林土壤质量排序为:油蒿+杨柴林地＞柠条锦鸡儿林地＞沙柳林地＞流动沙地,表明不同人工固沙灌木林的建植均能提高沙漠土壤质量,其中营造油蒿+杨柴半灌木混交林对提高土壤综合质量效果最好.     

沙漠植物的更新生态位Ⅰ．油篙、柠条、花棒的种子萌发条件的研究

本文从沙漠植物更新生态的角度,试验分析了油蒿、柠条和花棒种子萌发的条件,明确了三种灌木的累积发芽率与一次降雨量、连续阴天天数和种子埋藏深度之间的相依关系,阐明了它们适应沙漠严酷生境的各项特点的生态对策。     

The Dynamics of Seed Bank on Shapotou Artificially Stabilized Dunes

There were 46 species belonging to 17 families in the soil seed bank on Shapotou artificially stabilized dunes. Compositae was the family with most species '(11 species) and the others were Chenopodiaceae (7 species), Gramineae (7 species), Leguminosae (4 species), etc. 33.3 % of the species lived in the community also had seeds in soil. The seed production of Artemisia ordosica, Hedysarum scoparium, Caragana korshinskii was 545.57 ± 676.73 grains/m2. 6.67 ±13.74 grains/m2. 0. 032±0. 024 grains/m2, respectively. The seeds of A. ordosica were not destroyed by pests, but 31.9%, 83.29% of the seeds of H. scopariurn. C. korshinskii respectively were destroyed by pests. Under the most suitable burying depth, the cumulative seed germination rate of A. ordosica, H. scoparium, C. korshinskii were 78. 3%, 66.7%. 85.0%, respectively. The rate of germination was in the order of: A. ordosica>H, scoparium>C, korshinskii. The vegetation succession would tend towards community mainly consisted of A. ordosica, Bassia dasyphylla, Eragrostis poaeoides, etc.     

几种旱生灌木种子萌发对干旱胁迫的响应

以不同渗透势的PEG(6 0 0 0 )溶液 (- 0 .3～ - 2 .7MPa)为模拟干旱胁迫条件 ,研究了柠条 (Caraganakorshinskii)、花棒 (Hedysarumscoparium)和白沙蒿 (Artemisiasphaerocephala)种子发芽、幼苗生长和累积吸水率对干旱胁迫的响应 ,讨论了参试种子发芽特性、初生根长度与幼苗建植成活率的关系 .结果表明 ,干旱胁迫下柠条发芽率最高 ,其次为花棒 ,白沙蒿最低 . - 0 .3～ - 0 .6MPa渗透势下白沙蒿发芽 10d的初生根长度显著大于花棒和柠条 (P <0 .0 5 ) ,三者的测量值依次为 7.9、4 .5和 3.1cm .干旱胁迫条件下参试种子发芽率与种子 72h累积吸水率均呈极显著的正相关 (P <0 .0 1) .     

Seed germination and seedling emergence of three annuals growing on desert sand dunes in China

BACKGROUND AND AIMS: Information on the initial growth characteristics of annuals found in Chinese deserts is very limited. The aim of this study was to investigate seed germination and interactive effects of irrigation and seed burial depth in sand on seedling emergence and seedling survival in three annuals (Agriophyllum squarrosum, Bassia dasyphylla and Aristida adscensionis) commonly growing on sand dunes in these regions. METHODS: Effects of temperature, light and polyethylene glycol-6000 on seed germination were examined by irrigating seeds sown on filter paper in Petri dishes. Seedling emergence was examined for seeds sown on the surface of, or at different depths (5, 10, 20, 30, 40 and 50 mm) in, sand-filled pots, which were irrigated under different regimes. For seeds buried at a depth of 50 mm, seed viability was examined after irrigation of the pots. KEY RESULTS: Seeds of three species germinated at most temperatures recorded between spring and autumn in their native habitats. No seed dormancy was found in any species. For all three species, seedling emergence was most favoured when seeds were buried at a depth of 10 mm. When seeds sown on the sand surface were irrigated, seed germination was considerably suppressed due to water deficiency, but many seeds remained viable. For A. squarrosum and B. dasyphylla, many seeds that were deeply buried and irrigated remained ungerminated but viable, while for A. adscensionis deeply buried seeds germinated, but the seedlings did not emerge due to unfavourable seedling growth in deep sand. CONCLUSIONS: Precipitation is the most crucial factor in determining the seasonal emergence of seedlings of the three tested species in the field. The vertical distribution of seeds in sand determines the proportion of seeds that germinate after precipitation and acts to maintain seed banks over multiple years.     

不同风沙条件对几种植物生态生理特征的影响

 在野外风洞条件下,就不同风况的风沙胁迫对几种固沙植物生态生理特征的影响进行了实验研究。实验采用了沙坡头地区的野外植物和盆栽植物。在不同风速(5.9 m·s-1, 7.9 m·s-1, 9.9 m·s-1,14 m·s-1, 10 m·s-1,15 m·s-1, 20 m·s-1)和吹袭时间间隔(2 d, 4 d, 9 d)下测定了植物3个生理生态参数的变化。实验结果表明：1）净风和风沙流胁迫均可使植物的净光合速率（Pn）降低,蒸腾速率（E）升高,从而导致水分利用效率（WUE）下降。净风和风沙流对植物生理生态特征的影响显著不同。同样为14 m·s-1的风速时,风沙流使植物的Pn降低40.7%,而净风使其降低了35.88%。2）吹袭的时间间隔越短,植物的净光合速率降幅越大;风沙流比净风的影响更大。在2 d, 4 d, 9 d为间隔的风沙流吹袭下,油蒿（Artemisia ordosica）的Pn分别下降了20.13%、 11.76%、 7.72%。风沙胁迫强度越大,物质积累越少,植物的高生长越慢。3）由于风沙流降低了水分利用率,从而增加了对植物的干燥作用。从总体来看,沙生植物对风沙流胁迫有一定的适应响应,实验所用灌木较草本植物有更强的抗风性。     

干旱半干旱地区人工固沙灌木林生态系统演变特征

应用实验生态学方法分析了沙坡头地区栽植于1956、1964、1981、1987年的无灌溉人工植被固沙群落浅层土壤分形特征、植被盖度、物种特征、生物量、土壤水分、土壤微生物,以及群落土壤物理和土壤养分特征,并与流动沙丘进行比较。结果表明,在干旱半干旱的草原化荒漠地区,首先利用半隐蔽式草方格沙障对流动沙丘进行固定,然后栽植灌木柠条、花棒等和半灌木油蒿,经过40多年的稳定演变,该区域逐渐形成由矮灌木与草本植物覆盖,以及隐花植物与微生物土壤结皮复合的固定沙丘景观。在人工植被固沙防护体系稳定演变过程中,浅表层土壤的细粒化和养分富集化特征,微生物土壤结皮与亚表层土壤厚度,以及浅表层土壤体积含水率均随固沙年限的延长趋于显著增加。而土壤微生物数量、植被盖度、植物种数等生物群落学属性在固沙年限达40a左右时,已趋于最大,尔后呈缓慢下降趋势。随着固沙年限的增加,灌木树种不断衰退减少,当固沙年限逾17a之后,群落生物量增至峰值后略有下降。土壤分形维数与土壤粘粒含量呈显著正相关关系,流动沙丘被人工植被固定年代越久远,浅表层(0~3cm)土壤粘粒含量(4.50%)越高,其分形维数越大(D=2.4083),表明人工植被固沙防护体系浅表层土壤结构变得越紧实,流动沙丘(D=2.0484)在人工植被的固定作用下,发生逆转的趋势越显著,沙丘日趋固定。     

沙坡头地区不同配置格局油蒿和柠条水分生态位适宜度研究

利用生态位适宜度理论建立了沙坡头人工植被防护林体系无灌溉条件下,两种固沙植物油蒿(Artemisia ordosica Krasch．)和柠条(Caragana korshinskii Kom．)的水分生态位适宜度模型。并据此分析比较在5种不同配置格局下,在不同的降水量年份,这两种植物的水分利用状况。主要结论如下：不论在生长季总降水量为80.63mm的1991年还是在降水量大一倍的1993年,单播下油蒿的水分生态位适宜度均大于混播下的适宜度,且在7月份均有一个水分极其匮乏期;单播下柠条的水分生态位适宜度均小于混播下的适宜度;单播的3种格局中,以2m×2m的株距和行距(即样地1,3)为最佳,混播的两种格局以1m×1m的株距和行距,且按2行油蒿×2行柠条,中间空一行的方式配置(即样地5)为最佳。最后,对两个种生长过程中水分利用的一些特性进行了探讨。     

Comparison of Germination Strategies of Artemisia ordosica with Its Two Congeners from Deserts of China and Israel

Artemisia ordosica Krasch. is a dominant shrub occurring mainly on stable sand dunes in the Gobi Desert of China, in the Mongolian phytogeographic region. Achenes of A. ordosica germinate in light but poorly in dark and light is the limiting factor regulating the achene germination in sand depth. Achenes germinate in spring or autumn with an optimal temperature of 20 ℃. Achene mucilage can absorb large amounts of water and has important ecological function. Salt concentrations and sand moisture may regulate achene germination in sand. A. ordosica, A. sphaerocephala Krasch. and A. monosperma Delile. from different climates have similar responses to light, the underground location of achene, and sand moisture. Percentage of seedling emergence from different levels of sand depth is depends on the specific, temperature and intensity of light penetrating through the sand depths, as well as on sand moisture. The desert sand habitat seems to have had a dominant influence on the evolution of the germination strategies of these 3 Artemisia species.     

Emergence and Seedling Growth of a Cultivated and a Wild Strain of Safflower under Various Amounts of Simulated Rainfall

Two separate experiments were conducted to investigate the effects of different planting depths and irrigation regimes on the emergence and seedling heights of a cultivated (Carthamus tinctorius L. cv. Arak 2811) and a wild strain (C. oxyacantha Bieb.) of safflower. In the first experiment, three planting depths (0.5, 2.0 and 3.5 cm) and four water levels (6,9,12, and 15 mm) were used. Water was applied only once at the start of the experiment. For Arak 2811, the highest emergence percentage and seedling height were obtained when seeds were planted 0.5 cm deep in the soil and irrigated with the equivalent of 12 mm of rainfall. In the second experiment, five water levels (3, 6, 9, 12 and 15 mm) were applied at 3-day intervals for a period of 25 days and the planting depth was 0.5 cm. For Arak 2811, the seedlings emerged within 4 to 7 days after the first watering while for the wild strain, the emergence started on the 4th day and continued up to the 17th day. The emergence percentage of the wild safflower was almost half of that of the cultivated strain. However, the emerged wild seedlings were much more resistant to low available water than the seedlings of the cultivated variety of safflower.     

科尔沁沙地3种草本植物根系生长动态

利用微管对狗尾草(Setaria viridis)、黄蒿(Artemisia scoparia)和沙米(Agriophyllum squarrosum)根系生长动态进行了观测。结果表明:1)在观察期内,狗尾草和黄蒿的根系生长表现出先增后减的“抛物线”型,而沙米的根系成指数生长。在7月末至8月初狗尾草、黄蒿和沙米根系具有最高的生产量,其根量密度分别为4 690.91、2 975.76和2 354.55条·m^-2;在8月末,狗尾草和黄蒿根系都表现出不同程度的衰减,沙米根数保持增加。2)狗尾草优先生长表层根系,根系主要生长在0~30 cm的土层内,根长密度最大时为2.23 cm·cm^-2;黄蒿生长前期表层根长密度大,生长后期下层根长密度开始增加;沙米优先发展下层根系,快速生长期后,地下30~50 cm处的根长密度增加高于上层。3)生长前期和快速生长期,0~50 cm狗尾草根长密度最大,黄蒿次之,沙米最小,生长末期,沙米根长密度大于狗尾草。     

乌兰布和沙漠沙蒿与油蒿群落的物种组成与数量特征

沙蒿与油蒿群落均是我国最典型的沙地植被类型,在沙漠地区发挥了重要的生态防护作用,掌握其分布、组成及其数量特征对沙漠化防治具有一定的指导作用。调查研究表明,沙蒿与油蒿群落是乌兰布和沙漠典型的沙地植被类型,其中沙蒿群落多分布于沙漠中东部、南部和东北部,而油蒿群落仅分布于沙漠东部、东北部和东南部;其群落类型可划分为沙蒿群落、油蒿群落、沙蒿+油蒿群落、沙蒿+沙竹群落、沙蒿+花棒+沙拐枣群落、油蒿+白刺群落、沙蒿伴生群落和油蒿伴生群落;群落的物种组成比较简单,其中沙蒿群落共有9科21属22种,油蒿群落共有10科35属37种。草本植物是沙蒿与油蒿群落的主体,所占总物种数的比例均超过70%;Simpson、Shannon多样性指数和Pielou均匀度指数高,反映了沙蒿与油蒿群落具有较高的物种多样性。与沙蒿群落相比,油蒿群落物种丰富度、单位面积个体数、盖度、Simpson和Shannon物种多样性指数均明显大于沙蒿群落,而群落相似性显著低于沙蒿,说明乌兰布和沙漠油蒿群落较沙蒿群落具有更丰富的物种组成、多样性和群落结构,更具保护和人工促进潜力。研究结果可为乌兰布和沙漠沙蒿、油蒿群落的保护及人工促进提供理论基础,对区域沙漠治理物种选择具有一定的指导意义。     

四种植物种子萌发及苗期抗旱性差异的研究

对四种豆科植物种子萌发及苗期抗旱性作了比较研究,结果表示：种子萌发期抗旱笥强的植物其苗期抗旱性亦强。干旱引起组织脱水,植株生长受到抑制,幼苗出现衩始萎蔫时间与细胞膜受害时间一致。四种植物显示萎蔫时土壤含水量明显不同,红豆草为４．８０％、羊柴２．２％、花棒１．７４％、柠条１．５１％．据种子相对发芽率、膜透性变化等生理指标综合评定四种植物种子萌发及苗期抗旱能力次序为：柠条＞花棒＞羊柴＞红豆草。     

沙蒿与油蒿灌丛的防风阻沙作用

沙蒿与油蒿广泛分布于我国沙漠地区,是沙地植被的重要建群种和优势种。在腾格里沙漠南缘半流动沙地,实测了两种典型固沙植物沙蒿与油蒿的防风阻沙作用,从灌丛空间构型对比分析了其防风阻沙机制。结果表明,沙蒿与油蒿灌丛均具有明显的降低风速作用,但油蒿灌丛较沙蒿灌丛具有更显著的防风作用,而且对灌丛后不同位置、近地面不同高度层风速的降低程度明显不同。在灌丛后6倍株高范围内,沙蒿灌丛对50cm高度风速降低程度显著大于20cm,而油蒿灌丛对近地面20cm高度层风速降低程度显著大于50cm。在相同风速下,油蒿灌丛后20cm高度平均风速是沙蒿灌丛的1/2,而50cm高度平均风速与沙蒿灌丛相近。同时,沙蒿灌丛阻沙作用弱,而油蒿灌丛具有明显的阻沙作用,单株积沙体积达到45.2±16.1dm3,积沙重量达到72.1±25.7kg,油蒿灌丛积沙量大小与灌丛结构间存在显著的正相关。研究表明,紧密型结构的油蒿灌丛是较松散型结构沙蒿灌丛更为理想的防风固沙植物,其灌丛分枝数多、分枝角度小、生物量大且多分布在近地面层是具有显著防风阻沙作用的根本原因,该结论可为干旱区防风固沙植被建设物种选择提供依据。