| Marine oligosaccharides degraded from the polysaccharide in marine organismare a series of oligosaccharide fragments. Marine oligosaccharides have specialmolecule structure and biological activity that used as a new-style plant growthregulator，which are characterized with natural and physiological activity multiplicity.This paper took monocotyledon barley, wheat and tobacco cell suspension as studyobjects, studied the action effect of two marine oligosaccharides with differentconcentrations and electric charge on plants and the effect of regulating plants’ growthand eliciting plants’ defense responses of oligosaccharides on some preliminaryexploration were carried out.In the aspect of plant growth-promoting: The seeds of barley and wheat wereimmersed in alginate-derived oligosaccharide (ADO) and chitosan oligosaccharide(COS) of different concentration and then cultured in illumination box of24℃, thebest concentration of growth-promoting was obtained preliminary on the base ofgrowth indexes: leaf’s height, root’s length, leaf’s weight and root’s weight.Meanwhile, the paper was to explore the mechanism of oligosaccharides ongrowth-promoting by combining the physiological indexs in seeds’ germination andgrowth process: chlorophyll content of leaves, amylase activity of seeds and rootactivity of plant with the basic growth indexes. The results showed that the bestpromoting concentration of ADO on barley and wheat were different, which were at0.5%and0.25%respectively, but both of them had a better effect on growthpromoting between the concentration0.25%and0.5%, when the concentration was at0.75%it began to inhibit the growth of plant; the effect of COS on barley growthpromoting was as similar as wheat, the best promoting concentration of COS was at0.025%, and the promotion was weak when the concentration was at0.075%. Basedon the determination of physiological indexes of these monocotyledons, it showed that the oligosaccharides promoted seed germination and seedling growth throughimproving chlorophyll content, amylase activity and root activity. Therefore, the trendof physiological indexes was identical to that of plant.The field experiment of wheat: The wheat seeds were immersed byoligosaccharides before seeding, the effect of marine oligosaccharides on the yieldand quality was determined by single panicle weight, grain number, grain weight perspike,1000-grain weight and the content of grains’ protein and starch. The resultsshowed that: the single panicle weight, grain weight per spike and1000-grain weightof the wheat seeds reached4.06g,3.37g,71.80g, and the increment can reach26.7%,25.7%,17.9%compared with control group, the protein and starch content of grainsreached13.53%and60.39%and the increment improved6.14%and1.46%whenthey were treated by ADO at the concentration of0.25%; the increment of singlepanicle weight, grain weight per spike and1000-grain weight of the wheat seedsreached3.42g,2.86g,67.55g and the increment can reach6.7%,6.6%and10.9%compared with the control group, which was treated with COS at the concentration of0.025%, but there was no obvious effect on the quality of wheat grains’ improvement.Marine oligosaccharides can promote plant growth and improve physiological activity,simultaneous, can improve yield and quality in the late growth stage of crops.The experiment of tobacco cell suspension: the techology of cell suspensionculture is a new system of cell culture which appeared after callus induction. Thispaper studied the difference of dense volume and dry weight of cell by addingdifferent cocentrations of marine oligosaccharides into medium, which used tobaccocell suspension as the experimental material in order to determine the bestcocentration of marine oligosaccharides. The effect of oligosaccharides on elicitingplants’ defense responses was determined by combining the activity of defenseenzymes and accumulation of lignin in cells with cell growth curves. The resultsshowed that: the best cells’ promoting concentration of the oligosaccharide was at0.03%which was treated with different concentrations of ADO, the activitiy of theSOD, POD and CAT in cells reached maximum after adding oligosaccharides40min-50min and the activity of defense enzymes in plants was activated, the content of lignin was improved to20.87%and9.30%after adding oligosaccharides2d-5d,however, it began to inhibit the cells’ growth when the concentration was at0.05%;The best promoting concentration of the COS is at0.005%, the activitiy of the SOD,POD and CAT in cells reached maximum after adding oligosaccharides60min-70min,the content of lignin improved to45.17%and28.63%after adding theoligosaccharides2d-5d, but it began to inhibit the cells’ growth when theconcentration was at0.01%.The results showed that these two kinds of marine oligosaccharides can promotethe plant growth and improve the yield and quality of the crops through regulating thephysiological activity; they can induce the eliciting plants’ defense responses bystarting the signal transduction process and regulating the immune performance of thecells based on interacting each other with plant cells, which gave the scientific theoryfor applied on agriculture of marine oligosaccharides. |
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