【作者】 吕建亮；

【导师】 廖超英； 孙长忠；

【作者基本信息】 西北农林科技大学 ， 环境科学， 2009， 硕士

【摘要】 黄土高原丘陵区是世界上水土流失最严重的地区之一,在黄土高原半干旱区局部地段生长的土壤藻类能在严重干旱缺水、营养贫瘠、生境条件恶劣的环境中生长、繁殖,通过其生活代谢方式影响并改变环境。当前,对于环境因子影响藻类结皮形成与生长的研究涉及较少,因此,研究环境因素对藻类结皮的形成及生长有着重要意义。本研究通过野外调查和室内培养相结合的方式对环境因子进行测定,评价藻类结皮对各种环境条件变化的适应能力。室内培养运用单因素实验和完全组合实验,分析了氮素水平、水分,温度,光照等对土壤藻类生长的影响,确定了土壤藻类培养的优化营养条件和环境条件。本研究旨在揭示环境因素对藻类结皮形成过程的影响,从而为水土流失的治理提供科学依据。主要研究成果如下:1.植被类型对土壤藻类结皮盖度和厚度的影响呈现出不同的规律性。植被类型不同,藻类结皮盖度不同,荒坡>樟子松林>油松林。但结皮厚度表现出相反的特点,即油松林>樟子松林>荒坡地。2.坡向对土壤藻类结皮分布有极显著影响,阴坡藻类结皮盖度和厚度均大于阳坡;坡度对藻类结皮盖度的影响差异不显著;但对结皮厚度有明显的影响,即平缓坡>缓坡>陡坡>极陡坡。3.地貌部位对土壤藻类结皮分布有明显影响,林地结皮盖度表现为坡上部>坡中部>坡下部,结皮厚度无显著差异。荒坡地上、中、下坡藻类结皮盖度和厚度差异不大。干扰程度对藻类结皮分布具有极显著影响,干扰程度弱,藻类结皮盖度和厚度均较大,反之则小。4不同水分处理下,以土壤最大持水量的100%供水时藻类盖度最大,达到40.7%,其次为80%供水、60%供水、40%供水。20%供水时由于严重水分亏缺,藻类基本不生长。不同水分条件下,60%供水比40%供水藻类盖度大70.2%,80%供水比60%供水藻类盖度大87.5%,100%供水比80%供水藻类盖度大33.3%。5.土壤藻类在25℃时生长最好,15℃时的生长明显受到抑制,而50℃时土壤藻类基本不生长。从生长趋势来看,35℃下的土壤藻类生长速度很快,30d的培养已达到生长最高点,而15℃下的生长较缓慢,但如果延长培养时间,其生长量还可以增加。室内培养土壤藻类最适生长温度为15～35℃。在不同光照培养下,以7000lx光照强度和以18h/d的光照时间对土壤藻类的生长最有利。6.氮素水平对土壤藻的生长影响显著,不同氮素培养时以CO(NH2)2盖度、密度和株高均最高,分别为55%、36株/cm2和4.2mm。不同浓度培养时,随着NaNO3浓度提高,生长速率逐渐增大,提高氮素的浓度能促进土壤藻类的生长。7.温度、pH值、氮磷比三因素不同水平完全组合试验条件下,土壤藻生长量达到最大时的条件是温度25℃、氮磷比16∶1、初始pH值设定为8.2。更多还原

【Abstract】 The Loess Plateau Hilly and Gully Regions is one of the most serious soil erosion areas in the world. Soil algae which is grows in the Loess Highlands semi-arid region can not only endure the drought and barren conditions, but also can alter the environment. Presently, the research which is focus on the environment factors how to effect the algae’s formation and growth are few. Therefore, study on the effect of environmental factors in algae’s formation and growth have great meanings.This paper determinate the environment factors through the methods of the indoor rising and the open country investigation, to appraise the adaptive ability which algae mantle effect environmental. The indoor raising utilized the single factor experiment and the complete combination experiment, analyzed the constant element, the nutritional conditions, the moisture content, the temperature, the illumination, how to influence the growth of the soil-dwelling algae, and determined the soil algae’s optimism nutritional condition and the environmental condition. The purpose of research is for promulgating the environmental factor how to influence the algae mantle forming process, thus providing the scientific basis for soil loss control. The main conclusion was following:1. The different vegetation structures present the different regularity to the algae mantle’s degree of cover and thickness. When the vegetation structure was different, the algae mantle degree of cover was different. The soil aglae’s coverage under different vegetation structures ranked in order of barren slopes> Mongolian pine forest> Chinese pine forest. But the mantle thickness displaied the opposite characteristic, ranked in order of Chinese pine forest > Mongolian pine forest > barren slopes.2. The effect of different slopes on soil algae crust distribution were extremely obvious, the coverage and thickness of soil algae crust in the shady slope were bigger than that in the sunny slope; The different slope was not remarkable to soil algae crust’s distribution. The degree of disturbance had extremely obvious effection to the algae mantle degree of cover, the degree of disturbance was weak, the algae mantle degree of cover was bigger, otherwise was small.3. Parts of different landforms crust of algae had a significant effect on the distribution, in the woodland, the crust cover the performance of the Department for the slope> slope central> lower slope. Crust thickness had no significant difference. In the slopes, the upper, middle and downhill algae crust cover and thickness difference.4. Under different moisture content, the 100% water supply’s algae degree of cover was the biggest, achieves 40.7%, next was the 80% water supply, 60% water supply, 40% water supply. 20% water supply under the serious moisture content owes lacks, the algae did not grow. Under different moisture content condition, the 60% water supply was bigger 70.2% than 40% water supply degree of cover, the 80% water supply was bigger 87.5% than 60% degree of cover, and the 100% water supply was bigger 33.3% than 80% water supply.5. The soil-dwelling algae growth most well in 25℃, at 15℃, the growth suppresses of the soil-dwelling algae was inhibited. Moreover, the soil-dwelling algae dies basically at 50℃. Look from the long growth tendency, soil-dwelling algae growth speed was very quick at 35℃, the 30d raising had achieved the growth peak, but at 15℃the growth was slow, but if the time was prolong, its biomass could increase. Under the different illumination condition under the 7000lx strength of illumination and the 18h/d illumination time, soil-dwelling algae growth very well.6. The nitrogen level influence the soil algae’s growth remarkably, when took the CO(NH2)2 as the nitrogen source, the degree of cover, the density and plant height was most high, respectively was 55%, 36 /cm2 and 4.2mm. Under the different density of raising condition, when the NaNO3 density strengthened, the nitrogen assimilation also strengthened, the growth rate increases strengthened gradually, increase the density of nitrogen source can promoted the soil-dwelling algae’s growth.7. Temperature, pH, nitrogen and phosphorus levels of three different combination of factors under the condition of orthogonal experiment, soil algae growth conditions at the time of maximum temperature 25℃, nitrogen and phosphorus than 16:1, the initial pH value was set to 8.2.更多还原