塔克拉玛干沙漠腹地10种灌木光合器官的滞尘能力评价

通过全株光合器官取样,利用质量差减法,对塔中植物园10种灌木的滞尘能力进行多指标比较。结果表明：① 植物光合器官滞尘量与所处环境条件有关,在沙漠地区同种植物光合器官滞尘量大于沙漠以外区域。② 梭梭和沙拐枣的光合器官退化为同化枝,形态类似针叶树种的针叶,但尚有极度退化的叶片,其滞尘量大于其他区域针叶树种;与沙拐枣相比,梭梭同化枝节间距较短,叶片数量相对较多,因此梭梭的滞尘能力大于沙拐枣。③ 柽柳属植物虽然叶片也极度退化,但具有数量众多、分布密集、被覆绒毛、分泌盐分等特性,而且树冠光合器官密度大,具有很强的滞尘能力,光合器官滞尘量大于梭梭和沙拐枣,也大于阔叶灌木和阔叶乔木;由于光合器官表面滞尘特性、叶片数量以及树冠光合器官密度的差异,柽柳属植物光合器官滞尘能力也存在种间差异。④ 全植株光合器官滞尘量、单位重量光合器官滞尘量、单位表面积光合器官滞尘量都只能从一个侧面反映植物光合器官的滞尘能力,而单位树冠体积的光合器官滞尘量则可较全面地反映植物光合器官的滞尘能力。以单位体积树冠空间光合器官滞尘量为评价指标,10种灌木光合器官滞尘能力的排序为：甘蒙柽柳>长穗柽柳>华北柽柳>紫杆柽柳>刚毛柽柳>多花柽柳>多枝柽柳>沙生柽柳>梭梭>头状沙拐枣。

Evaluation on Dust-holding Capabilities of Photosynthetic Organs of Ten Shrub Species in Hinterland of the Taklimakan Desert

In this paper, the photosynthetic organs stained with dust on the whole plants of 10 shrub species planted in Tazhong Botanical Garden in the hinterland of the Taklimakan Desert were sampled, and their dust holding capabilities were analyzed using the multiple indices in mass subtraction method. The results were as follows: (1) Dust holding capabilities of plant photosynthetic organs are closely related to the environment. The plants growing in the desert hinterland can hold more dust by their photosynthetic organs than those growing in the peripheral regions of the desert; (2) Though photosynthetic organs of Haloxylon ammodendron and Calligonum caput-medusae degenerated into the assimilative branches with extremely degenerated leaves similar to needles of coniferous species, their dust holding capabilities are higher than those of coniferous species mentioned in other paper. The dust holding capabilities of photosynthetic organs of H. ammodendron are higher than those of C. caput-medusae because of its assimilative branches with shorter knot spacing and more leaves; (3) Though leaves of Tamarix plants also degenerated extremely, they have the excellent dust holding capabilities by their photosynthetic organs, higher than H. ammodendron and C. caput-medusae, and even higher than broad leaved shrubs and broad leaved trees, because of their photosynthetic organ surface characteristics (such as the relatively bigger leaf size, abundant tomenta and salt secretion), a mass of leaves, and greater photosynthetic organ density of crown. Therefore, the dust holding capabilities of these Tamarix plants mentioned in this paper are distinctly different; (4) Photosynthetic organs of the whole plants, unit weight and unit surface area can only represent the dust holding capabilities in some aspects, but dust holding amount of unit volume crown can represent the dust holding capabilities of photosynthetic organs of plants more holistically. The dust holding capabilities of photosynthetic organs of 10 shrub species are in an order of Tamarix austromongolica > T. elongata > T. juniperina > T. androssowii > T. hispida > T. hohenackeri > T. ramosissma > T. taklamakanensis > H. ammodendron > C. caput-medusae. These results may provide a scientific basis for tree species selection and distribution in landscaping and shelterbelt construction and dust holding effect evaluation, and also a reference in studying the correlation between plants and soils in arid regions.