腾格里沙漠固定沙丘藓类植物结皮层的自然恢复及人工培养试验研究

Experimental studies on the natural restoration and the artificial culture of the mosses crusts on fixed dunes in the tengger desert

通过藓类结皮层的自然恢复和人工培养藓类植物促进结皮层形成试验,研究了腾格里沙漠固定沙丘生物结皮层形成过程中优势成分真藓(Bryum argenteum)的繁殖生物学特性,结果表明:藓类结皮层人工去除后在3～4年内70%的样方基本恢复,在此过程中真藓主要靠茎叶碎片传播和繁殖;通过分株法、撒茎叶法培养的真藓在一个月后长满整个样地,主要通过如下方式繁殖——茎的碎片连续分枝可产生小植株,茎、叶均可产生原丝体,由原丝体发育产生小植株,小植株又可再生原丝体,如此反复产生新植物体,这一过程是野外人工促进生物结皮层形成过程中真藓主要的繁殖途径。与室内培养中真藓的繁殖特性相比较,野外培养的真藓在繁殖过程中产生的原丝体较粗壮,分枝多,但在两种条件下的繁殖特性相同,能够揭示该地区自然条件下藓类植物萌发和定居的繁殖机理。该研究为人工促进生物结皮层形成及治理受损结皮层提供了实验依据。

Soil microbiotic crusts cover extensive portions of the arid and semiarid regions of theworld, and play an important ecological role. Moss is one of the major components in the crusts. The reproduction and establishment of the mosses are crucial to the formation of mosses crusts. Bryum argenteum is the dominant species of mosses crusts in the Shapotou region (37°27′ N, 104°57′ E) of the Tengger Desert. In search for the characteristics of the natural reproduction and establishment, 10 quadrates (10cm×10cm for each) were obtained by removing the moss crusts in different positions of fixed dunes. These 10 quadrates were observed for three years on end upon the species components and the coverage. Meanwhile, in the third year, 2 quadrates (1m×1m for each) were set up in a crust-absent area, 2 different experiments of the asexual reproduction (broadcast planting and offshoots) were respectively done. The reproductive process was observed under the microscope, and the morphological indicators of the new individuals were measured. The results were compared with the ones of indoor experiments using the same methods. All the results showed as follows: 1) 70% quadrates (i.e. 7 of the ten quadrates) were recovered within 3-4 years, thus the quick recovery might be due to the dispersal and reproduction of the fragments of stems and leaves of B. argenteum; 2) As for the 2 quadrates in the artificial reproduction test, the new plants occupied the uncovered space of the quadrates in one month, and there were two main reproduction approaches, one of which was that the stems continually branched and produced young plants, and the other of which was that the young plants and the fragments of the stems and leaves repeatedly and extensively reproduced protonema which developed into a large number of new plants finally; 3) The reproductive characteristics were identical, though the protonema in the field was more robust and had more branches than the ones indoors.