中文摘要：

齿肋赤藓（Syntrichia caninervis）是荒漠藓类生物结皮的主要组成物种,在沙面固定及生物结皮人工恢复中起着十分重要的作用。然而,人工培养的荒漠藓类植物普遍存在后期维持能力较差的问题。在众多的影响因素中,水分被认为是限制荒漠齿肋赤藓生长发育的最关键环境因子。该文以室内人工培养的齿肋赤藓为研究对象,模拟野外降雨条件,在室内对其进行干旱处理（每6天加水,模拟夏季少雨、干旱缺水条件）、完全湿润处理（每天加水,模拟春季融雪或降雨较频繁、水分饱和条件）及中度湿润处理（每3天加水,模拟介于前两种之间的水分条件）3种水分梯度处理,探讨不同的水分条件处理对人工培养的齿肋赤藓光合及生理特性的影响。结果表明：与中度湿润处理相比,人工培养的齿肋赤藓的总叶绿素含量在湿润处理和干旱处理两种水分梯度处理下均显著下降,叶绿素a/b在干旱处理下显著降低,类胡萝卜素含量在湿润处理下显著下降,在干旱处理下显著升高;湿润处理及干旱处理下人工培养的齿肋赤藓的最大光化学效率、实际光化学效率和可溶性蛋白含量均显著低于中度湿润处理,而可溶性糖含量、脯氨酸含量、过氧化氢酶、过氧化物酶、超氧化物歧化酶活性和丙二醛（MDA）含量大都显著高于中度湿润处理,尤其是干旱处理。完全湿润处理下齿肋赤藓植株渗透调节物质含量及保护酶活性的升高有效地缓解了高水分含量带来的缺氧及低光照环境对人工培养的齿肋赤藓的损害。干旱处理下的MDA含量显著升高,说明干旱胁迫处理加剧了人工培养的齿肋赤藓的膜脂过氧化程度,对其细胞膜的稳定性造成了一定损害。因此,在人工培养苔藓后期,干旱和完全湿润处理都不利于苔藓植物的生长,中度湿润处理则有利。

英文摘要：

Aims The desert moss Syntrichia caninervis is a dominant species in the moss biocrust of the Gurbantünggüt Desert. It plays an important role in soil stability and artificial biocrust reconstruction in desert ecosystems. Previous studies have demonstrated that although artificial cultivation techniques can promote the micropropagation of S. caninervis, the resulting moss performs poorly in maintenance ability. Water availability has been considered as a critical factor to stimulate the physiological activities in moss species. Our objective in this study was to determine the optimum water condition for growth of sand-cultivated shoots of S. caninervis in the process of transplanting cultured materials from laboratory to the field. Methods We used sand-cultivated S. caninervis grown from fragmented gametophyte leaves and stems above ground. The experiment was run for 30 days under conditions of three water treatments, including intermittent water supply（watering every three days）, fully watered（watering every day）, and drought（watering every six days）. Fluorescence and physiological indices of shoots, such as photochemical efficiency, pigment content, soluble sugar, free proline, soluble protein, catalase, peroxidase, superoxide dismutase activities and malondialdehyde were measured. Important findings The content of total chlorophyll, chlorophyll a and b in drought and fully watered treatments were significantly lower than in intermittent water supply treatment. Drought reduced the chlorophyll a/b ratio, and fully watered treatment deceased carotenoid content. Drought and fully watered treatments significantly reduced the maximal and actual photochemical efficiency and the soluble protein content, while increased most indices in osmotic adjustment substances and antioxidative enzyme activities, such as soluble sugar content, free proline content, catalase, peroxidase, superoxide dismutase and malonaldehyde content. Our results showed that the sand-cultivated S. caninervis accumulated osmotic adjustm