不同生态因子对青藏高原东缘沙化区生物结皮中藻类生长发育的影响

Effects of Different Ecological Factors on Growth and Development of Algae in Biological Crust in Eastern Margin Desert Region of Qingzang Plateau

为研究不同生态因子对青藏高原东缘沙化区藻类生长发育的影响,以筛选出沙化区藻类生长的最适条件,采集沙化区不同区域和深度的土样后,装入无菌袋并保存于-20℃冰箱.制备不同浓度的土壤悬液,均匀接种于无菌BG11固体培基上,在光/暗=16 h/8 h,25℃条件下培养1个月.挑取单一的藻落接种于BG11液体培养基中进行纯化培养,比较不同pH值、Na+浓度和Mg2+浓度下藻落的数量.结果表明,中性环境下,吸光度随培养时间的延长而增加;pH=5时,藻种一在第13 d吸光值达到最高值随后开始降低;而pH=9、11时吸光度最大值出现在第15 d;藻种一的生长过程与Na+浓度和Mg2+浓度存在剂量依赖性.说明荒漠藻类能耐一定的碱,当碱性太强则会影响它的生长;盐浓度与藻类的生长均呈负相关.

Objective：To investigate the effects of different ecological factors on growth and development of algae in biological crust in eastern margin desert region of Qingzang plateau and find out the best cultivating conditions.Methods：Samples were obtained from every sampling areas,loaded in abacterial pockets and stored at-20 ℃.Different concentrations of soil suspension liquid were prepared and coated homogeneously on sterile BG11 solid cultural medium at light/dark=16 h/18 h and 25 ℃ for one month.Chose single algae and inoculated in BG11 liquid nutrient medium to pure culture,and compared the number of algae in different pH,Na＋ concentration and Mg2＋ concentration.Results：In the neutral condition,the absorbency increased as culture time expanding;the absorbency of species 1 reached the maximum and began to reduce on the 13th day,at pH=5;the maximal absorbency attained on the 15th day,at pH=9 or pH=11;there is dose dependent between the growth process of species 1 and Na＋ concentration and Mg2＋ concentration.Conclusion：The desert algae has some resistance to alkali,however,strong basicity would affect the growth of algae.It appears to be inverse relationship between algae growth and salinity.