Influence of Medium and Light Intensity on the Leaf Explant Browning in Phalaenopsis sp. in vitro

The browning ratio of Phalaenopsis sp.leaf explant in vitro growing on MS liquid paper bridge and 1/2MS after 10d is 0 and 67%,respectively,less than that growing on MS,B5 and N6.Doubling the content of FeSO4 or microelement deficiency could increase the browning rate of explant cultured in MS medium.Reducing the content of agar could increase the degree of browning.The higher the intensity of light,the more serious the explant browning.Explant cultured on medium supplemented with citric acid showed a considerable reduction in browning.Adding Vit C,active carbon or PVP could not overcome the browning of explant.