Studies On Pollen Cold Storage And Cryopreservation Of Chimonanthus

Plants of Chimonanthus are used as important landscape materials with high ornamental value. Procedure of pollen cold storage and cryopreservation, pollen viability after storage, physiological and physiochemical indexes' changes before and after cryopreservation were studied here. By means of plentiful experiments, cryopreservation procedure was established primarily. The results showed:1. The procedure of pollen cryopreservation was stated as following. After drying for 24h at the stationary temperature of 25℃, pollen could be plunged into LN2 without being-frozen. Then water at 37℃ was used for pollen thowing.2. The basic pollen germination medium of Chimonanthus was 15%sucrose+7% agar+1.5mg/L 2, 4-D+50mg/L H3BO3+0.05%Ca2+. Adjusting the concentration of indigrents in the medium had effect on pollen germination. But pollen germination rates of H11 H29 H46 H50were highest on the medium when the combination of ingredients was arranged as stated above.3. The storage temperature was an important factor affecting the pollen life span. Room temperature (22℃ ) and 4℃ were suitable for pollen short-time storage(10-15d). For instance, Pollen of H8 H11 H89; at -20 ℃ -70℃ -196℃, storage period of pollen could be prolonged. After one-year conservation in LN2 germination rates of H29 H50 H5 pollen were respectively 21.027% 23.136%, 1.623% higher than before storage. The results showed that cryopreservation was a valid way for pollen of most genotypes to keep for a long period of time. For example pollen of H29 H50 H82 H86 H5.4. As drying time prolonged, pollen viability increased. But when drying time reached 36h, pollen germination rates began to decrease. By setting six different dehydration time(4h 8h 12h 16h 24h 36h) and testing pollen germination rates at the respective time stated above, the optimal drying time for pollen of Chimonanthu confirmed by contrast was 24h.5. Pre-frozen temperature and thowing ways affected pollen cryopreservation. Plunging pollen into LN2 directly and thawing in 37℃ series water was better for pollen storage effect.6. As sheltered enzyme, SOD POD CAT activity took different changes after cryopreservation than before. Stress at -196℃ mainly accelerated the improvement oftheir activity. MDA was one physiological resistance index of pollen. After cryopreservation, the increase of MDA content in pollen indicated that membrane peroxidation enhanced, system of membrane was injured. LN2 storage also imposed effect on material metabolism of pollen.Thus the soluble protein content fluctuated in the procedure.