Effects Of Application Of Seaweed Extract Combined With Copper, Iron And Boron On Nutritive Peculiarity Of Rape (Brassica Campestris L.)

In recent years, seaweed extract has been increasingly used as fertilizer, soil conditioners and plant growth modifier in agricultural production. However, little is known about the application effect of the seaweed extract as fertilizer and its acting mechanism. And further study need to be done on the effect of co-application of seaweed extract and trace element fertilizer. We took the lead in studying co-application of sea extract and trace elements of Cu, Fe and B so on effect on seed burgeoning, nutritive peculiarity and ability of unti-salt stress of the rape, by the method of nutrimental solution incubating, aiming to provide scientific basis for proper utilization of fertilizer and sea bioresource. The main results obtained were stated as follows:1. Sea extract or it combined with B applications significantly promotes rape seed burgeoning, with the increasing rate of 8.27% and 7.69% compared to control, respectively.2. Dry weight of rape with sea extract application alone, it application combined with Fe, it application combined with Fe and Cu, or it application combined with Fe, Cu and B, increases by 2.97%, 53.81%, 63.98% or 86.02%, respectively, than that with control. The application of sea extract combined with Fe, Cu and B significantly promotes rape growth, and enhances trunk height, leaf number, leaf area and dry weight.3. Fe application significantly elevates leaf chlorophyl content and photosynthesis rate of rape, and the effects are found more significant under co-application of sea extract and Fe, with the photosynthesis rate of up to 24.66 mol CO2 m-2 s-1, increasing by 64.07% and 88.17% than that under Fe application alone and sea extract application alone treatments, respectively. The treatments of co-application of sea extract and Fe significantly increases rape leaf photosynthesis rate, 6 to 8 times than that with control. Sea extract application alone does not have obvious influence on rape leaf chlorophyl content and photosynthesis rate.4. Sea extract combined with Fe, Cu and B application can promote nutrients uptake of rape. The most significant effect thereinto is observed in N or P uptake by rape aboveground under sea extract combined with B application, 1.15 or 1.08 times that respective that under control, respectively. The uptake mass of N, P, K, Cu, Fe and B by rape with sea extract combined with Fe, Cu and B application is 1.65, 1.55, 1.71, 1.61, 2.01 and 2.52 times than respective that with control.5. Compared to trace element fertilizer application alone, the co-applications of Fe and Cu, Cu and B, or Fe and B significantly reduce rape trace element contents, suggesting the inhibiting action occur among the trace elements. While, the co-application of sea extract contributed to balance uptake of N, P, K and micro element nutrients by rape.6. Application of sea extract can elevate resistant ability of rape to salt stress. Under salt stress, sea extract application relatively reduces rape leaf MDA content, alleviates the damaged degree of rape protoplast film osmosis, and meanwhile effectively promotes accumulation of praline in rape leaf.