Effects Of Aluminum On Physiological And Ecological Characteristics Of Solanum Khasianum And Plantago Asiatica

The prime objective of the present investigation is to observe the effect of various concentrations of aluminum along with different durations on the invasive plant Solanum khasianum and the native plant Plantago asiatica.The observations include the change of growth characteristics,physiological nature,photosynthesis characteristics and reproductive characteristics. The findings of the investigation are as follows:1).Low concentration of aluminum had very little or no effect on the growth of Solanum khasianum and Plantago asiatica.Leaf area,leaf number,root growth and biomass above ground found to be drastically decreased at high concentration of aluminum.The height and caudex of Solanum khasianum was inhibited by the high concentration of aluminum.2).Very little effect was noticed on the physiological characteristics of Solanum khasianum and Plantago asiatica at low concentration of aluminum.The membrane permeability and the content of malondialdehyde(MDA)increased with the increased concentration of aluminum and as well as increased treatment days.The content of Proline in the leaf of Solanum khasianum rises significantly alongwith the increased aluminum concentration and prolonged treatment duration. Plantago asiatica,on the other hand had high proline content at high concentration of aluminum but significantly decreased with the increasing duration of treatment.Similarly,the soluble sugar contents ascends with short period of treatment with high aluminum concentration and descends alongwith increasing time.When the aluminium concentration exceeds 500mg/L,the activity of SOD,POD and CAT were increased,which indicates that the plant had initiated the process of tolerance against stress conditions by upgrading its protective enzyme system. Under Al stress situations,the damage of cell membrane of Solanum khasianum were found to be less serious than that of Plantago asiatica.The increasing of proline in Solanum khasianum are more significant than that of Plantago asiatica.So does the activity of SOD.The result indicated that the invasive plant Solanum khasianum could have ability to reduce stress through the mechanism of physiological defense.3).Aluminum stress noticed to have influenced the photosynthesis,photoresponse curve and fluorescence parameter.Under the aluminum stress,the content of both chlorophyll and carotenoid went up in Plantago asiatica.The chlorophyll content of Solanum khasianum also increased while carotenoid in Solanum khasianum ascends fast and later descends.The aluminum stress reduced the Pn,Gs,Tr and WUE in both Solanum khasianum and Plantago asiatica,While Ci in both enhanced.According to the photoresponse curve,treatment with low concentration of aluminum made Amax,AQE,Rday and LSP of Plantago asiatica increased,and so does LSP of Solanum khasianum.With increasing of Al concentreation,Amax,AQE,LSP of Solanum khasianum showed descending tendency,and the change of Rday and LCP of Solanum khasianum ascending tendency.It demonstrate that the photosynthesis of Solanum khasianum could be promoted by low concentration of aluminium,while high concentration of aluminum could weaken seriously. The chlorophyll fluorescence parameter were reduced by the stress of aluminumUnder the 500mg/l Al³⁺treatment,the influence of photoresponse curve and parameter on Plantago asiatica was found to be greater than on Plantago asiatica.The Amax,AQE,LSP of Plantago asiatica reduced significantly under that concentration.However there was no change in Solanum khasianum.The results showed that the invasive plant Solanum khasianum could reduce stress through the mechanism of photosynthesis defense.Solanum khasianum showed more resistive toward Al in aspect of photosynthesis characteristics.4).The plant reproductive growth was inhibited intensively by the aluminum stress.Under the 2000mg/l Al³⁺treatment,the two plants could not bloom while under the 800mg/l Al³⁺treatment,. the flowering stage was delayed.The whole process reduced the flower number,the spike number.The spike length was greatly decreased.