海岸桐的抗旱生物学特性

南沙群岛土壤主要以珊瑚砂为主,由于其光照强、土壤水分和养分贫瘠等环境条件,导致很少植物能够在岛上正常生长。为了快速恢复南沙岛礁的植被,需要筛选出抗旱性强的植物并进行引种。海岸桐(Guettarda speciosa)是一种典型的热带海岸植物,在海岛和海岸带防风固沙及植被生态恢复等方面发挥着重要作用。该文以西沙永兴岛自然环境下的海岸桐为研究材料,对其形态解剖学特征、抗氧化能力、抗逆性物质含量及营养元素含量等进行了研究。结果表明:(1)随着干旱程度增强,海岸桐栅栏组织与海绵组织的比值和叶片厚度等结构都会增加,能有效减少植物体内水分的流失,节水能力较强;(2)其体内的超氧化物歧化酶和过氧化氢酶活性快速增加,脯氨酸含量也不断增加,证明海岸桐有较强的抵御干旱的调节能力;(3)其根部营养物质含量少但叶片营养物质含量高,叶绿素总含量减少的速度慢,说明海岸桐能够高效利用养分且受干旱胁迫的损害程度小。综上所述,海岸桐抗旱能力强,能在土壤水分的环境下正常生长,可引种于南沙岛礁。

iological characteristics of drought resistance of Guettarda speciosa

Due to the environmental conditions of Spratly Islands, such as strong sunlight, poor soil moisture and nutrient, few plants can grow normally on the island. In order to restore the vegetation ecology of Spratly Islands, drought-resistant plants should be selected and introduced. Guettarda speciosa is a typical tropical coastal plant, which plays an important role in windproof and sand-fixing in island and coastal zones and vegetation ecological restoration. We studied the morphological and anatomical characteristics, antioxidant capacity, stress resistant material contents and nutritional element contents of paulodendrum under the natural environment Yongxing Island of Paracel Islands. The results were as follows:(1)The ratio of palisade tissue to sponge tissue, leaf thickness and other structures increased with the increase of drought degree, which could effectively reduce the water loss in plants and save water;(2)The activities of superoxide dismutase and catalase in the body increased rapidly, and the contents of proline also increased continuously, which proved that G. speciosa has a strong ability to resist drought;(3)The contents of nutrients in the root were low, but the contents of nutrients in the leaves were high, and the rates of total chlorophyll contents decreasing were slow, indicating that G. speciosa can use nutrients efficiently and suffer little damage from drought stress. It can be concluded that G. speciosa has strong drought resistance ability and can grow normally in the environment with poor soil moisture, which can be introduced to Spratly Islands.