The Cryopresevation Of Oncidium Protocorm Like Bodies By Vitrification And Their Physiological And Histological Characteristics Analysis

Oncidium belongs to Orchidaceae Subribe Oncidiinae.Because of its special flower shape,outstanding flower color,it has been called one of "the five beauty" of cut flower arranging flowers.At present,there are more and more pieces of Oncidium,and germplasm resources conservation become more and more important.Thus establishing a suitable and effective preservation method becomes very important.Here Oncidium PLBs were employed as the test material.And the main factors effective on cryopreserved-vitrification of Oncidium were investigated.1.The optimized conditions for cryopreserved-vitrification of Oncidium PLBs were:(1)Oncidium PLBs were dried 3 hours on the super clean hood,then pretreated with 50%PVS2 at room temperature for 15 minutes;(2)Successively treated with 100%PVS2 for 10 minutes;(3)PLBs were put into and stored in liquid nitrogen;(4)The cryopreserved-vitrification PLBs were thawed in 40? water bath;(5)The cryopreserved-vitrification PLBs were rinsed with 1.2mol/L sucrose solution for 3 times,and 10 minutes/time.2.The effects of drying during cryopreserved-vitrification on the physiological and biochemical characteristics of Oncidium PLBs.Our results showed that after drying treatment,the soluble sugar content,the soluble protein content and antioxidant enzyme activities first increased then declined,indicating that drying pre-treatment may enhance the frost resistance.This study suggests that a suitable pre-treatment method is essential to ensure a higher survival rate.3.The histological structure of Oncidium PLBs from different stages of cryopreserved-vitrification was observed by staining the paraffin sections.The results showed that the PLBs' structure was significantly changed after cryopreserved-vitrification.The vitrification and liquid nitrogen cryopreservation and thawing were all harmful to Oncidium PLBs.While suitable pre-treatment can effectively reduce these injuries.And loading with vitrification solution before the vitrification process can also decrease the dehydration hurt.