The effect of different concentrations of DA-6 and DCPTA on the form and quality of Yellow Mauritius pineapple was studied.The results showed that the 10,50 mg/L of DA-6 increased the average weight of single fruit by 12.42% and 11.88%,respectively,but the same concentration of DCPTA increased that by 7.49% and 2.55%,respectively.Different treatments could increase fruit longitudinal diameter and pineapple morphological index,reduce core diameter,enhance contents of soluble solids,Vc and soluble sugar,decrease organic acid content,and improve pineapple quality.

NaCl,MnSO4 and NaH2PO4 were respectively sprayed on the leaves of pineapple(Bali variety) 20 and 30 days after anthesis in order to investigate the effects of these chemicals on the quality and stress resistance of pineapple fruits.The results showed that spraying of NaCl,MnSO4 and NaH2PO4 increased the single-fruit weight by 15.37%,18.83% and 10.01%,respectively.All these treatments could increase the content of total soluble solid(TSS) and vitamin C,and MnSO4 treatment was the best,which decreased titratable acid content and increased superoxide dismutase(SOD) and peroxidase(POD) activities,but had no effect on total surge content.In collusion,MnSO4 and NaH2PO4 treatments can increase the quality of pineapple,and MnSO4 is superior to NaH2PO4.

The effects of Rare Earth on the yield and quality and protective enzymes of Pineapple were studied by field experiments.The results showed that the effects of 200 mg/L Cerium nitrate treatment were the best.The width and length of pineapple fruits increased by 5.08%,10.82%;Fruits quality increased by 20.13%;Vitamin C improved by 135.81% and Sugar-acid ratio improved by 17.75%;SOD activity increased by 69.96% and POD activity reduced.