梭梭次生木质部解剖特征及其可塑性研究

Secondary Xylem Anatomical Structure and Its Plasticity of Haloxylon ammodendron

为揭示梭梭对干旱环境的适应性,对古尔班通古特沙漠南缘梭梭次生木质部解剖结构进行观测,研究次生木质部解剖特征的可塑性。结果表明:梭梭次生木质部解剖结构中,导管有宽导管和窄导管2种,导管频率和导管复孔率较高,导管个数较多,导管壁和纤维壁明显增厚,Vulnerability值和Mesomorphy值较小,因此梭梭对干旱环境的适应性强。2种土壤类型中,沙质类型的导管壁厚、导管频率、导管复孔率、导管长度和纤维壁厚显著高于土质类型,而纤维长度则极显著低于土质类型,表明沙质类型梭梭比土质类型具有更强的抗旱性。梭梭次生木质部解剖结构对水分条件具有较强的可塑性,使古尔班通古特沙漠的梭梭具有更宽的生态幅和更好的抗旱性,从而成为该沙漠的优势种。

In order to reveal the environment adaptability of Haloxylon ammodendron to drought stress, the anatomical structures of secondary xylem of H. ammodendron in southern Gurbantiinggiit desert were examined, and the plasticity of secondary xylem anatomical structures were studied in this paper. The re- sults showed that the secondary xylem with the narrow and wide vessel elements, the high vessel frequen- cy, the low percentage single pores, the numerous vessels, thick-walled vessels and fibres, could lead to smaller vulnerability and mesomorphy value. Therefore, the adaption of H. ammodendron to drought was high. Compared with the loam type, the thickness, frequency and length of vessels, percentage of pores in clusters and thickness of fibres were significantly higher in sandy type. The length of fibres was signifi- cantly lower in sandy type, which indicated that the plant in sandy type was more drought resistant than in loam type. It was concluded that, the secondary xylem anatomical structures of H. ammodendron with high plasticity for water stress lead to wider ecological amplitude and better drought resistance. H. arnmo- dendron become a dominant species in Gurbanttinggiit desert consequently.