论文部分内容阅读
羽毛针禾(Stipagrostis pennata)是古尔班通古特沙漠流动沙丘的先锋禾草和优良固沙植物,本研究从形态结构、理化特性、生物学特性等方面对其复杂的根区生境进行了分析。结果表明:①野生羽毛针禾能够形成特殊的根鞘结构(即由土壤颗粒与根表分泌物及根毛、菌丝体相互胶结、缠绕形成的特殊结构),使根区环境相对稳定;②根鞘的存在可有效扩大根系与土壤的接触面积,有利于根系-土壤信息交流及水分和养分的交换,对植物忍耐干旱逆境胁迫尤为重要;③根鞘的形成明显改善了其所在微生境的土壤条件,根鞘含水量可达外围土壤的5倍,成为潜在的水库;根鞘的形成明显改善了养分尤其是氮素累积状况,其全氮含量显著高于外围土壤,速效氮、微生物量氮含量极显著(P<0.01),高于外围土壤;根鞘微生境呈碱性,pH值略低于外围土壤;④根鞘中碱性磷酸酶、脲酶、多酚氧化酶、蔗糖酶等各类水解酶、氧化酶均极显著(P<0.01)高于根外围土壤,反映出根鞘微生物学过程较强、土壤肥力较高,可有效增加土壤有机碳氮的转化,促进根鞘微生境养分循环;⑤可培养微生物分析结果显示,细菌在根鞘微生境中占绝对优势(99.72%±0.09%);可培养微生物优势类群为芽胞杆菌属(Bacillus)、链霉菌属(Strep-tomyces)、青霉属(Penicillium)。上述微生物具有固沙、固氮、解磷、产抗生素等生态潜能,有助于改善羽毛针禾根区营养吸收,促进植株生长。因此,作为对高温、缺水恶劣环境的一种应答结构,根鞘的形成促进了植物根土界面的信息交流及水分和养分的交换,有利于植物、土壤、微生物建立互惠互利的关系,对植物忍耐干旱逆境胁迫尤为重要。
Stipagrostis pennata is a pioneer grass and sand-fixing plant in the mobile sand dune of the Gurbantunggut Desert. In this study, the complex root zone habitat was analyzed from the aspects of morphology, physico-chemical characteristics and biological characteristics . The results showed that: (1) Wild Featherhead can form a special root and sheath structure (ie, the special structure formed by soil particles and root exudates, root hairs and mycelium cemented and entangled with each other) The existence of sheath can effectively enlarge the contact area between root system and soil, which is beneficial to exchanging root-soil information and exchange of water and nutrients, which is particularly important for plants to tolerate drought stress. ③ The formation of root sheath significantly improves the soil of the micro-habitat Under the condition, the water content in the root sheath reached 5 times of that in the peripheral soil, and became a potential reservoir. The formation of root sheath significantly improved the accumulation of nutrients, especially nitrogen, and its total nitrogen content was significantly higher than that of the peripheral soil, available nitrogen and microbial biomass nitrogen (P <0.01), which was higher than that in the peripheral soil. The root sheath was alkaline and the pH value was slightly lower than that in the peripheral soil. ④ The contents of alkaline phosphatase, urease, polyphenol oxidase and sucrase (P <0.01) were higher than that of the root periphery soil, which indicated that the root sheath was more microbiologically and had higher soil fertility, which could effectively increase the conversion of soil organic carbon and nitrogen and promote the root sheath microbial environment Nutrient recycling ; ⑤ Microbial analysis showed that the bacteria accounted for the absolute superiority in root sheath micro-habitat (99.72% ± 0.09%); Bacillus, Strep-tomyces, Penicillium. The above microorganisms have the ecological potential of fixing sand, fixing nitrogen, releasing phosphorus, producing antibiotics, etc., and help to improve the nutrient absorption in the root zone of the feather and promote the growth of the plant. Therefore, as a response structure to the harsh environment of high temperature and water shortage, the formation of the root sheath promotes the exchange of information and the exchange of water and nutrients at the root-soil interface, which is conducive to the establishment of mutually beneficial relations between plants, soil and microorganisms. Plant tolerance to drought Stress is particularly important.