土壤基质中细物质含量对人工蓝藻结皮形成的影响

Effects of fine substance content in soil substrate on the formation of artificial cyanobacteria crusts

利用人工蓝藻结皮进行生态修复是防治沙漠化的有效方法之一,土壤细物质是限制人工蓝藻结皮拓殖和发育的重要因子之一。流沙中细物质含量较低,为了促进人工蓝藻结皮在流沙中的发育,本研究设置细物质和流沙体积比为0∶1、1∶1、2∶1、4∶1和1∶0共5个处理,比较了不同细物质含量人工蓝藻结皮的生长状况。结果表明:随着细物质含量的增加,人工蓝藻结皮的盖度逐渐增大,叶绿素a含量和胞外多糖含量先增大后略有下降。土壤细物质和流沙体积比为4∶1处理下人工蓝藻结皮发育最好,该处理下培养60 d后,人工蓝藻结皮的盖度为70%,叶绿素a含量为17.5μg·cm^(-2),松散结合胞外多糖含量为70.0μg·cm^(-2),紧密结合胞外多糖含量为175.0μg·cm^(-2),糖被胞外多糖含量为200.0μg·cm^(-2)。在细物质含量较低的条件下增加蓝藻添加量可以促进人工蓝藻结皮的形成和发育(每个培养皿添加0.5 g蓝藻为最优处理)。本研究为人工蓝藻结皮接种体规模化培养提供了新思路。

The use of artificial cyanobacteria crusts is one of the effective methods to prevention and control of desertification.Soil fine substance is one of the important factors limiting the colonization and growth of artificial cyanobacteria crusts.We compared the growth of artificial cyanobacterial crusts with different fine substance contents by setting the volume ratios of fine substance to quicksand as 0:1,1:1,2:1,4:1 and 1:0.The results showed that the cover of artificial cyanobacteria crusts increased gradually with the increases of fine substance contents,while the contents of chlorophyll a and extracellular polysaccharide firstly increased and then decreased slightly.The optimum growth of artificial cyanobacterial crusts was achieved under the treatment of 4:1 ratio.Under such treatment after 60 days of incubation,artificial cyanobacteria crusts cover was 70%,and the contents of chlorophyll a,loosely bound exopolysaccharide(LB-EPS),tightly bound exopolysaccharide(TB-EPS),and glycocalyx exopolysaccharide(G-EPs)were 17.5,70.0,175.0,and 200.0μg·cm^(-2),respectively.Increasing the amount of cyanobacteria under the condition of low fine substance content could promote the formation and growth of artificial cyanobacterial crusts(0.5 g of cyanobacteria per petri dish was the optimal).It could provide a new idea for the large-scale culture of artificial cyanobacterial crusts inoculum.