作 者 ：李芳兰,包维楷,庞学勇,冷俐
期 刊 ：生态学报 2009年 29卷 5期 页码：2219~2230
Keywords:dry valley, endemic species, microhabitat, seedling establishment, vegetation restoration,
摘 要 ：为了阐明干旱河谷自然条件下乡土植物种子出苗与幼苗定居能力的空间差异性，选择环境适应能力较强的植被恢复物种，试验选择岷江上游干旱河谷水热条件具有明显差异的两个试验地点：四川省茂县撮箕山（南坡）和两河口（北坡），采用4因素随机区组设计，开展大量的野外播种对比试验，研究了微生境类型改变及不同播种处理方式对白刺花（Sophora davidi (Franch.) Skeels.）、小马鞍羊蹄甲（Bauhinia faberi var. microphylla）、岷谷木蓝（Indigofera lenticallata Craib）、落芒草（Oryzopsis munroi Stapf）和川芒（Miscamthus szechuanesis Keng）5种干旱河谷乡土植物种子出苗、幼苗存活及生长的影响。发现：（1）在干旱河谷自然气候条件下，播种后1个月是所有受试植物出苗的高峰期，但是种子出苗率都很低，达不到30%；幼苗存活能力也极低，在播种1个月后所有幼苗死亡数量增加而保存数明显下降；在播种2个后幼苗存活数均为0。相同条件下小马鞍羊蹄甲、岷谷木蓝与落芒草的出苗数量明显高于白刺花和川芒。这说明干旱河谷地区种子出苗与幼苗存活的限制是自然植被更新能力弱，并且恢复困难的主要原因。（2）种子出苗及幼苗存活能力在不同区域之间具有明显的差异，湿润地段种子出苗数量与幼苗保存数量都较大。但是，种子出苗及幼苗存活能力在同一地段灌丛、半灌丛与裸地等不同类型的微生境之间无明显变化。（3）小容器播种能够有效地增加种子出苗率与短期幼苗存活，但是未能提高幼苗最终的存活能力及生长速率；采用保水剂与腐殖质土壤改良措施对种子出苗数与幼苗保存数没有明显影响，因而这些措施不能解除干旱河谷地区极端环境胁迫对幼苗定居的阻碍。
Abstract:Although many scientists have primarily concentrated on vegetation restoration in the dry valley of Minjiang River, few species have been demonstrated to be suitable for the restoration now. We investigated seedling emergence, survival, and growth of five endemic species, Bauhinia faberi var. microphylla, Sophora davidii (Franch.) Skeels, Indigofera lenticallata Craib, Oryzopsis munroi Stapf and Miscamthus szechuanesis Keng in order to assess the species′ ability of drought tolerance and the spatial difference in seedling establishment. Seeds of the five species were collected in October 2005 from the dry valleys in Maoxian County, Sichuan Province, China. The seeds were treated with 2.5% of sodium hypochlorite (NaOCl) for 1h and healthy seeds were sowed from May 19 to 23, 2006, for a field experiment. The experiment was arranged using a Completely Randomized Block Design with four factors: two contrasting field sites (wet Zuojishan and dry Lianghekou sites), five species, two microhabitats (vegetated and bareland patches), and three seeding treatments (direct seeding, potted seeding with humus, and potted seeding with soil in dry valley). Seedling survival, height and leaf number were recorded three times: June 25, July 23 and August 23, 2006. All observed species exhibited the flash of seedling emergence after 1 month since sowing. B. faberi var. microphylla, O. munroi and I. lenticallata presented greater seedling emergence and survival than M. szechuanesis and S. davidii. However, dieback of all the seedlings was observed in both study sites after 2 months since seeding, although seedling lived longer in the wet site than in the dry site. The seedling emergence, survival and leaf number of the five species were not significantly affected by microhabitat type and seeding treatments. Nevertheless, seedlings of the five species were more likely to establish under the potted seeding conditions than the direct seeding treatment. These results show that low seedling establishment resulting from environmental stress is a vital factor limiting population regeneration of those native species and vegetation restoration success in the dry valleys of Minjiang River.
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