盐碱胁迫对香樟幼苗根际土壤酶活性的影响

摘要

The potted camphor seedlings of two years were taken as the materials and were treated by the mixed solution of salinity-alkalinity (Na2CO3︰NaHCO3 = 1︰1) with different concentrations (0, 50, 100 and 200 mmol/L), the enzyme activities and pH of rhizosphere soils were studied. The results showed that pH value of rhizosphere soil increased with the stress time and concentration of salinity-alkalinity; Urease activity of 0 mmol/Ltreatment showed an increasing trend, but those of salinity-alkalinity stress increased first and then degreased. Urease activity increased with the increase of salinity-alkalinity concentration. Catalase activity showed an increasing trend, and it also increased with the increase of salinity-alkalinity concentration. Invertase activity increased first and then decreased, and it decreased with the increase of salinity-alkalinity concentration. Alkaline phosphatase activity was promoted under slight salinity-alkalinity stress (0–50 mmol/L) but restrained under severe salinity-alkalinity stress (50–200 mmol/L). Proteinase activity of 0 mmol/L treatment showed an increasing trend, but inhibited under salinity-alkalinity stress. The conversion of available nutrients in soil and nutrient absorption by plants are influenced by salinity-alkalinity stress.%以2年生盆栽香樟幼苗为材料,分别施用0、50、100、200 mmol/L的Na2CO3和NaHCO3(1︰1)混合溶液,研究盐碱胁迫对香樟幼苗根际土壤酶活性的影响.结果表明:随着盐碱胁迫时间的延长,各处理土壤pH不断上升,且随盐碱处理浓度越高,pH越大;对照的脲酶活性呈不断上升的趋势,盐碱胁迫处理的脲酶活性呈先升后降的趋势,盐碱处理浓度越高,土壤脲酶活性越小;过氧化氢酶活性呈不断上升的趋势,盐碱处理浓度越高,过氧化氢酶活性越大;土壤蔗糖酶活性呈先升后降的趋势,盐碱处理浓度越高,土壤蔗糖酶活性越小;轻度(0~50 mmol/L)盐碱胁迫程度促进碱性磷酸酶活性,而重度盐碱(50~200 mmol/L)胁迫抑制碱性磷酸酶活性;0 mmol/L处理的蛋白酶活性不断上升,而盐碱胁迫抑制蛋白酶活性.盐碱胁迫影响了土壤中有效养分的转化.