Seedling germination technique of Carex brunnescens and its application in restoration of Maqu degraded alpine grasslands in northwestern China

Carex brunnescens(Pers.)Poir.is considered to be the only clonal herb found to date that can develop and form fixed dunes in Maqu alpine degraded grasslands of northwestern China.However,due to strong dormant characteristics of C.brunnescens seeds,the sand-fixing effect of the plant is severely limited.This study explores a technique that can rapidly promote the seed germination of C.brunnescens,and also investigates the adaptation and sand-fixing effect by cultivating C.brunnescens seedlings to establish living sand barriers in the sand ridges of moving sand dunes.Results show that the seed germination rate obtained a maximum of 63.7%or 65.1%when seeds were treated with 150 mg/L gibberellic acid(GA3)for 24 h followed by soaking in sulfuric acid(98%H2SO4)for 2.5 min or sodium hydroxide(10%NaOH)for 3.5 h,and then germinated(25°C in daytime and 5°C at nighttime)in darkness for 10 d.After breaking seed dormancy of C.brunnescens,the living sand barrier of C.brunnescens(plant spacing 15−20 cm;sand barrier spacing 10−20 m)was established in the perpendicular direction to the main wind in the middle and lower parts of the sand ridges on both sides of the moving sand dunes.When the sand ridges were leveled by wind erosion,the living sand barrier(plant spacing 15−20 cm;sand barrier spacing 0.5−1.0 m)of C.brunnescens was reestablished on the wind-eroded flat ground.Finally,a stable sand-fixing surface can be formed after connecting the living sand barriers on both sides,thus achieving a good sand-fixing effect.These findings suggest that rapid seed germination technology combined with the sand−fixing method of C.brunnescens can shorten the seed germination period and make the seedling establishment become much easier which may be an effective strategy to restore and reconstruct Maqu degraded grasslands.

Sand-fixing characteristics of Carex brunnescens and its application with straw checkerboard technique in restoration of degraded alpine meadows

Carex brunnescens（Pers.）, a typical clonal species, is considered to be the only herb found to date that can develop on sand dunes in Maqu alpine region of northwestern China. However, the characteristics that C. brunnescens resists to harsh alpine environment have not been documented. In this study, we conducted a field investigation to determine the morphological, reproductive, and sand-fixing characteristics of C. brunnescens. Concomitantly, we transplanted the belowground rhizomes of C. brunnescens to sand dunes and compared the abilities to restore degraded alpine meadows among sand dunes that had no further treatment（SD＋N）, sand dunes that had straw checkerboard technique but no transplanted rhizomes of C. brunnescens（SD＋SCT）, and sand dunes that had both SCT and transplanted rhizomes of C. brunnescens（SD＋SCT＋P）. We found that belowground vertical rhizomes and horizontal rhizomes（including branching rhizomes and main rhizomes） of C. brunnescens were highly developed and that population reproduction was dominated by horizontal rhizomes. C. brunnescens exhibited a significant sand-fixation effect under following conditions： population density was 145–156 ramets/m^2, vegetation cover was 31.2%–39.3%, total length of belowground rhizomes was 11,223 cm/m^2, total length of belowground first-order roots was 9161–10,524 cm/m^2, fresh weight of aboveground part was 198.5–212.6 g/m^2, and fresh weight of belowground part was 578.8–612.4 g/m^2. It should be particularly noted that SD＋SCT＋P treatment（sand dunes that had both straw checkerboard technique and transplanted rhizomes of C. brunnescens） was the best and SD＋N（sand dunes that had no further treatment） was the worst in terms of following biotic indicators： total number of reproductive ramets, total number of belowground rhizomes, and fresh weight of aboveground and belowground parts of C. brunnescens, contents of soil organic carbon, available nitrogen, microbial biomass carbon, and microbial biomass nitrogen. It implies that applying SCT in sand dunes and transplanting belowground rhizomes to sand dunes with SCT could improve both soil fertility and growth of C. brunnescens. These results suggest that the SCT-promoted high reproductive abilities of belowground rhizomes of C. brunnescens can successfully facilitate the establishment of ramets and can thus be an effective strategy to restore degraded vegetation in Maqu alpine region of northwestern China.

Biological Characteristics of Carex brunnescens for Sand Fixation in the Source Region of the Yellow River

Carex brunnescens, a pioneer plant that has an excellent ability to fix sand in the source region of the Yellow River （Maqu）, plays an important role in maintaining the ecosystem stability of alpine grassland in Maqu. In this study, the biological characteristics （phonological characters, the growth process of overground and underground organs, and the morphological characters of underground organs） of C. brunnescens were studied by a field observation experiment. The results showed that C. brunnescens had the characteristics of turning green earlier than other plants, a long growth period, and two flowering and fruiting cycles. The leaf width, length and number of a single plant, and the density, coverage and leaf density of community increased significantly from the leaf extension period to the fruit mature period and then tended to be stable in the withering period, while the plant height and leaf area of a single plant and the leaf area of community rose significantly at first and then decreased. Underground stems （horizontal and vertical stems） and roots of C. brunnescens could survive in sand at a depth of 0-60 cm. The number of middle roots （0.2-0.5 mm in diameter） was the largest in all soil layers （0-20, 20-40 and 40-60 cm）, and the total length of fine roots （〈0.2 mm） were the maximum in the sand at a depth of 20-40 cm, while the total length of middle roots was the maximum in the sand layer at a depth of 0-20 cm. The length, fresh weight and dry weight of the main root, horizontal and vertical stems was the maximum in the sand layer at a depth of 10-30 cm and was the minimum in the sand layer at a depth of 40-50 cm. It is concluded that C. brunnescens can well adapt to the alpine sand habitat of Maqu, can be used as the constructive species for ecological restoration in the alpine desertified grassland of Maqu, and has good popularization and application prospects.

面向草地退化区域的褐鳞苔草种植技术研究

【目的】在面向草地退化区域的褐鳞苔草种植方面,传统的技术往往效果不佳,导致褐鳞苔草生长状况较差,存活数量有限,无法达到预期目标。为了解决这一问题,提出了面向草地退化区域的褐鳞苔草种植技术研究。【方法】首先,选择褐鳞苔草品种时考虑了草地退化区域的气候条件和土壤状况。然后,选择了适应力强、对环境适应性好的品种,以确保种植的成功率和生长状况。为了提高褐鳞苔草的发芽率,进行了催芽处理。通过科学地调整光照、温度和湿度等因素,促进种子的发芽和生长。并利用育苗基质进行苗木的培育。选用富含养分的基质,并合理添加有机肥料,为苗木提供良好的生长环境,从而帮助其更好地适应退化草地的条件。最后,经过精心培育的苗木被移植到草方格沙丘内。认真安排移植的时间和方法,并注意对移植后的苔草进行适当的护理管理,例如浇水、施肥等,以确保它们能够顺利生长并逐步恢复草地的生态功能。【结果】经过试验证明,采用这种设计技术种植的褐鳞苔草具有良好的生长状况,存活基数也相对较大。【结论】表明该种植技术具有广阔的应用前景,并可以为草地退化问题的治理提供有力的支持。

玛曲县沙漠化草地褐鳞苔草固沙特性初探

褐鳞苔草(Carex brunnescens)是玛曲县沙漠化草地固沙的先锋植物,对维护玛曲高寒草地生物多样性和生态系统稳定性有重要作用。为了揭示褐鳞苔草种群的繁殖及固沙特征,对其地下部分的形态结构与种群繁殖特征,种群密度和地下部分数量指标与积沙特征的相互关系进行了研究,结果表明:褐鳞苔草地下茎(水平茎)高度发达,当地面被风沙覆盖后,地下水平茎会迅速延长并在茎节点上长出垂直茎,垂直茎快速向上生长并穿透沙面形成新的植株(沙埋深度小于50 cm),周而复始使地下茎形成多层网状结构,起到固沙作用。当种群密度小于146株/m2、地下茎直径小于1.40mm、一级根系直径大于0.627 mm时存在明显的风蚀现象;种群密度为146~158株/m2、地下茎直径为1.40 mm、一级根系直径为0.612~0.627 mm时固沙效果较好;种群密度大于158株/m2、地下茎直径大于1.40 mm、一级根系直径小于0.612 mm时出现明显的堆积现象。以上结果表明,通过人工辅助和工程措施,褐鳞苔草可作为玛曲高寒沙漠化草地生态治理的优良草种,具有良好的推广应用前景。

不同处理对褐鳞苔草种子萌发的影响

为摸清褐鳞苔草种子的休眠机理、萌发过程,解决种子繁育难题,对褐磷苔草种子用物理(热水浸种、机械处理、层积催芽)、化学(浓H2SO4浸种、NaOH溶液处理、GA3处理)及综合方法处理后进行萌发试验。结果表明:褐磷苔草存在休眠,且休眠程度较高,使用10%NaOH溶液可以打破休眠,将自然条件下不萌发的种子发芽率提高到13.75%,其次是切破种皮+GA31000mg/L,种子发芽率达到12.5%。

黄河源区退化草地褐鳞苔草种植技术及对土壤改良效果研究

【目的】探索高寒退化草地褐鳞苔草种植及改良土壤的技术方法。【方法】采用随机区组试验设计,野外温室条件下开展ABT6号生根粉、播种深度和育苗基质处理对褐鳞苔草种子出苗及苗木生长的影响;然后将苗木种植至铺设有草方格的沙丘上,观测其生长适应性及对土壤肥力的提升效果。【结果】用20 mg/kg的ABT6号浸种12 h,盆栽穴播深度0.5~1.0 cm时种子出苗和成苗效果最好;以50%草炭土+25%珍珠岩+25%蛭石混合,50%亚高山草甸土+30%高寒风沙土+20%腐熟羊粪混合,45%草炭土+54%高寒风沙土+1%复合肥混合3种基质育苗成苗率均达95%以上,且差异不显著。与未做任何措施的沙丘和未做任何措施的沙丘移栽褐鳞苔草相比较,铺设草方格的沙丘种植褐鳞苔草2年后其植被覆盖度分别增加了34.9%和18.1%,种群密度增加了423.9%和55.1%,地下茎总长度增加了648.6%和170.7%,总生物量鲜质量增加了319.8%和117.6%;且根区0~15 cm土壤有机质提高了177.6%和49.8%,速效钾提高了202.6%和56.6%,速效氮提高了138.6%和48.0%,速效磷提高了170.8%和29.5%。【结论】褐鳞苔草种子繁育苗种植在铺设有草方格的沙丘后其生长适应性良好,可显著提高土壤肥力,该技术在高寒退化草地上具有较好的推广应用潜力。

黄河源区褐鳞苔草的固沙生物学特性

褐鳞苔草(Carex brunnescens)是黄河源区(玛曲)沙漠化草地具有较强固沙能力的先锋植物,对维护玛曲高寒草地生态系统稳定性有重要作用。为了揭示褐鳞苔草固沙的生物学特征,本研究在野外观测了其物候学特征,地上和地下器官生长进程以及地下器官形态学特征。结果表明,褐鳞苔草返青早,生育期较长,具有二次开花和结果的生长特性。褐鳞苔草单株叶宽、单株叶长、单株叶片数量、群落密度、群落盖度和群落叶片密度从展叶期-果实成熟期-黄枯期呈显著增加而后趋于稳定;而单株叶丛高度、单株叶面积和群落叶片面积呈显著增加而后减小的趋势。褐鳞苔草地下茎(水平茎和垂直茎)和根系适宜生存的沙层深度为0-60cm。不同沙层深度(0-20、20-40和40-60cm)均以直径为0.2~0.5mm的中根数量最多,在20-40cm沙层内细根(<0.2mm)的根系总长度均最大,0-20cm沙层内中根根系总长度最大。在10-30cm沙层内,水平茎,垂直茎和主根长度、鲜重和干重均最大,40-50cm沙层内最小。以上结果表明,褐鳞苔草能很好地适应高寒风沙生境,可作为玛曲高寒沙漠化草地生态恢复的建群种,具有良好的推广应用前景。