生物结皮对5种不同形态的荒漠植物种子萌发的影响

生物结皮广泛分布于干旱、半干旱区, 强烈影响着土壤表层理化特性, 进而对种子散布、萌发和定居产生影响。目前关于生物结皮与植物种子萌发关系的研究结论存在争议。该文通过室内人工控制实验, 研究了生物结皮对古尔班通古特沙漠5种具不同种子形态特征的荒漠植物白梭梭(Haloxylon persicum)、蛇麻黄(Ephedra distachya)、角果藜(Ceratocarpus arenaarius)、涩芥(Malcolmia africana)和狭果鹤虱(Lappula semiglabra)的种子萌发的影响。结果表明, 在干燥和湿润两种条件下, 生物结皮对不同形态植物种子萌发均具有不同的作用。在干燥条件下, 生物结皮显著抑制了角果藜和涩芥种子的萌发(p<0.05), 对其它3种植物无显著影响; 而湿润条件下, 生物结皮显著抑制了白梭梭、角果藜和狭果鹤虱种子的萌发(p<0.05), 对蛇麻黄、涩芥则无显著影响。

EFFECTS OF BIOLOGICAL CRUSTS ON THE GERMINATION OF FIVE DESERT VASCULAR PLANTS WITH DIFFERENT SEED MORPHOLOGIES

Aims As a universal, common feature in arid and semi-arid regions, biological crusts can affect soil surface properties which may relate to seed dispersal, germination and establishment of vascular plants. Numerous studies have addressed aspects of the influence of crusts on vascular plants; however, the interaction between crusts and vascular plants is controversial. Our objective was to examine effects of biological crusts on seed germination of desert vascular plants with different seed morphologies in Gurbantunggut Desert, China. Methods Gurbantunggut Desert, the largest fixed and semi-fixed desert in China, has well-developed biological crusts. We conducted a series of shadow experiments to examine the effects of biological crusts on seed germination of Haloxylon persicum, Ephedra distachya, Ceratocarpus arenaarius, Malcolmia africana and Lappula semiglabra. Important findings The effects of biological crusts on germination were variable under both moist and dry conditions. The presence of crusts significantly reduced germination of Ceratocarpus arenaarius and Malcolmia africana compared with surfaces from which the crusts had been removed, but there was no significant effect on germination of the other species under dry conditions. Under moist conditions, seed germination of Haloxylon persicum, Ceratocarpus arenaarius and Lappula semiglabra was significantly lower on crust than on the surface devoided of crust, and there was no significant effect for Ephedra distachya and Malcolmia africana. In general, biological crusts affected the germination of some vascular plants, but whether the effect was negative or positive depended on water condition and biological characteristics of the seeds.