Study On Fluctuating Asymmetry(FA) As An Indicator To Alkaline And Saline Soil

Soil salinization is an important environmental issues. Soil salinization affects soilphysical and chemical properties, resulting in reduced soil productivity. Soil salinization hasrestricted the economic and social sustainable development. In recent years, more and moreresearchers are concerned about the adverse impact of ecosystems degradation on organisms.Biological indicators are important for assessing environmental conditions because biologicalresponses is the comprehensive effects of environmental changes. It is crucial to choose anindicator both easily operative and sensitive. Many studies have shown that plant fluctuatingasymmetry (FA)is an ideal biological indicator that can be used to measure the level of thepressure on the environment or the adaptive ability of organisms. But there is few reports onFA as an indicator to saline and alkaline soil.In this paper, Iris lactea was selected as an indicator plant. We mainly studied dynamicsof leaves fluctuating asymmetry, biomass, proline content and malondialdehyde in differentsaline-alkali soil in the growing season. We also compared FA among Iris lactea,Chlorisvirgata and phragmites communis under different soil salinity gradient. Results are showed asfollows:(1) In Soil salinity-alkalinity complex stress, the leaves fluctuating asymmetry (FA) ofthe Iris lactea can be used as an indicator. From May to September of fuctuating asymmetry(FA)、malondialdehyde(MDA) and proline in Iris lactea leaf decreased with increasingof EC and pH; biomass of in Iris lactea decreased with increasing of EC and pH.Fuctuating asymmetry (FA), proline and biomass reached maximum in August,andmalondialdehyde(MDA) decreased with increasing of month..(2) The leaves fluctuating asymmetry (FA) of the Iris lactea can be used as the earlyindicators of soil saline when the soil electrical conductivity (EC) in the range from727.8us/cm、to1007.4us/cm and pH from9.358to9.83, in which FA, biomass, MDA andproline in Iris lactea leaf began to increased significantly.(3) FA of the Iris lactea for monitoring the soil salinization are not more sensitively whenEC was from932μs/cm to1164μ s/cm and pH was from8.55to9.2.,FA value inPhragmites communis leaf began to increased significantly when EC value was from536μs/cm to914μs/cm and pH was from8.61to8.86. FA in Chloris virgata began to increasedsignificantly when EC value was from536μs/cm to975μs/cm and pH was from8.67to8.86,.