Allelopathy Of Suaeda Glauca On Crops And Pasture Grasses

Allelopathy is a type of effect that a plant exhibits to stimulate or inhibit the growth ofinterspecific or intraspecific plants through releasing some sencondary metabolites. S.glauca is a kind of halophytic plant, and it must accumulate some ions to regulate osmoticbalance. The metabolites from S. glauca plants can enter into the environment throughrainfall, fog or root secrete and have effects on the growth of other species or their ownspecies. The research on the allelopathy of S. glauca is very important to study thestructure of community and Songnen grassland deterioration.S. glauca was selected as the research material, using water extract to analyse the cellmitotic of lettuce root tips, the growth of wheat seedling and the activity of POD, SOD andCAT, determin the allelopathy of aboveground of S. glauca plants, analysis themechanism of allelopathy preliminarily. Based on the results, the bioassay of seeds andprimary growth of crop and pasture grass were measured, and the differences of effectsbetween S. glauca extract and equivalent electric conductivity of NaCl aqueous werecompared. Additionally, according to the growth law of S. glauca in the field, thequantities of phenolic substances in S. glauca plants and soil at different growth stageswere measured during the research, and the activities of PAL were studied along with thechange of seasons.The mitotic index of lettuce cell at root tips was decreased by S. glauca extracts.During the prophase and the metaphase, the cells of root tips were much more than thoseof the anaphase and the telephase (more than twice). Cell shapes were destroyed, andchromosomes were abnormally, such as chromosome trail, and chromosome-bridge.Compared with that of hypocotyls, the growth of wheat radicles were more sensitive toallelochemicals from S. glauca extracts. S. glauca extracts had effect on the activities ofPOD, SOD and CAT in wheat seedlings. These antioxidant enzymes could resist the effectof allelopathy through raising their activities. The higher the concentration increased, thestronger the activity of enzyme presented.Compared with the effects of equivalent electric conductivity of NaCl aqueoussolution, S. glauca extracts had more significant effects on receptor plants, whichdepended on the concentrations and the kinds of receptors. The seed germination rates of R.sativus, S. glauca, C.virgata were stimulated at low concentrations, and inhibited at highconcentration, while those of cucumber, sorghum, barley, K.sieversiana, A.anethifoliawere suppressed. With the concentration increased, the suppressive effects were raised.The effects of allelochemicals on activity index were presented more siginificantly thanseed germination rate. All concentrations of S. glauca extracts had inhibitive effect on theactivity indexes of all receptor plants, and the higher the concentration the more siginificant the inhibitive effects presented. Different receptor plants also responded to thesame concentration differently. The results showed that crop seeds were more sensitivethan pasture grass seeds.There were phenolic substances in most plants, and most phenolic substances hadbeen identified as allelochemicals. Allelochemicals could enter into the soil throughrainfall, and the research results showed that the quantities of phenolic substances weredifferent at different growth stages in S. glauca plants and soils. Both were higher atseedling growth stage and reproductive stage than that at vegetative growth stage. Thequatities of phenolic substances in plants were much higher than those of soil. Theactivities of PAL were raised with the season variation.