Effects Of Fertilization And Preservative On The Quality And Physiology Of The Culm For Fewflower Wildrice On The Mountains

Fewflower wildrice(Zizania latifolia) is a kind of important aquicolous vegetable.However,in recent years its production has not increased significantly and its quality has reduced due to the variations of cultivation systems and the blindfold use of a large amount of fertilizers.At the same time,the use of the fertilzer has also badly polluted our environments and increased the occurrence of plant diseases and insect pests.In addition,the young stem of fewflower wildrice can be preserved for only 3～5 days under the normal temperatures,which has affected its market circulation.In this study,the effects of the fertilization and the measures of the storage and preservative on the quality of fewflower wildrice,which is grown on Yuexi mountains,have been systematically studied.The main following results are obtained:(1) The Vitamine C contents evidently increase under the treatments of the medium-level N, high-level K and the high-level N and K.However,they are lower under the low-level N.The Vc contents in the single-season fewtlower wildrice are all higher than those in the double-season fewflower wildrice.The use of more N and K fertilizers can increase the Vc content in the single-season fewflower wildrice.The protein content in the double-season fewflower wildrice is lower under the low-level N or no use of N fertilizer while it is higher under the medium-level N. The P use can significantly increase the protein level in fewflower wildrice.The single-season fewflower wildrice showed lower protein level,and the addition of more P and K fertilizers can significantly increase the protein level in fewflower wildrice under the high-level N.The middle-level N and the appropriate proportion of P and K fertilizers can favor the sugar accumulation in fewflower wildrice.The addition of more P and K fertilizers can increase the sugar content of the double-season fewflower wildrice under the middle-level N and the absence of P and N fertilizers. The K fertilizer has an important effect on the sugar content in the single-season fewflower wildrice.(2)When more N fertilizer was added,the double-season fewflower wildrice showed higher nitrate content.The addition of more K fertilizer can decrease its nitrate content under the same N level.The addition of the N fertilizer has an insignificant effect on the nitrate content in the single-season fewflower wildrice when no organic fertilization is added.The addition of K fertilizer did not significantly decrease the nitrate content in the single-season fewflower wildrice under the same N level.The nitrite and nitrate contents showed a significantly negative correlation in both the single- and double-season fewflower wildrice.(3) The contents of some elements have evident differences under the different fertilization treatments.The N,P and K mixed fertilizers with the different proportion did not significantly affect N,P and K contents in fewflower wildrice.However,the different N,P and K mixed fertilizers had an important effect on the Pb,Fe,As,Se and Hg levels in fewflower wildrice,indicating that fewflower wildrice absorbed these elements from the soils with the selectivity.The contents of the nutrient elements(N,P and K) have also an important effect on the absorbability to other elements. Therefore it is very necessary for the production of high-quality fewflower wildrice that N,P and K fertilizers keep a proper mixed proportion and balance with other mineral elements during the nutrient element regulation and management.(4) The different preservatives had a different effect on the storage quality of fewflower wildrice grown on Yuexi mountains under the low temperatures.Results showed that the respiration rates of fewflower wildrice gradually increased with the days and then rapidly fell down.The slowest respiration rotes occurred in the fewflower wildrice treated by the mixture of GA and Sodium Benzoate,followed by special reagent of fewflower wildrice and GA.The hardness in the bottom and central parts of fewflower wildrice fell down with the days and it was relatively stable or slightly increased in the upper parts.The variations of the hardness in all parts of fewflower wildrice treated by the mixture of GA and Sodium Benzoate were slower than those by other treatments.During the storage,the content of the soluble sugar generally decreased and the slowest decreasing rates were also found in fewflower wildrice treated by the mixture of GA and Sodium Benzoate.The Vc and protein contents also decreased and the differences between the treatments were insignificant. Therefore the treatment of GA+ Sodium Benzoate mixture is the best method for the storage of fewflower wildrice.(5) The SOD and CAT activities in fewflower wildrice fell down during the low-temperature storage via the different preservative treatments.However,the POD activity all slowly increased with the date.In addition,the MDA content in fewflower wildrice gradually increased with the date during the low-temperature storage.