Studies On Callus Induction And Mechanism Of Browning And Control Methods In Loquat

In this study, anthers of’6-6-6’loquat (Eriobotrya japonica L.) were used as experimental materials, a series of studies were carried out on the callus induction, determination of total phenolic content and browning related enzyme activities in anther callus. Preliminary study on the mechanism of anther callus browning, and find the effective measures to control the browning of anther callus. Conclusions of the study are as follows:1. The microspore developmental stages were closely related to external morphological characteristics and anther color, the transverse diameter and vertical diameter of the buds were positively correlated with the development stages of the microspore. When the transverse and vertical diameters of flower buds were 4.68mm and 4.96mm respectively, anther color was yellow green, the microspores were at the late-uninucleate stage which were suitable for anther callus induction.2. Low temperature pretreatment time:low temperature pretreatment at 4℃ for 1 day resulted in the highest callus induction rate(71.11%), but with the treatment time prolonged, the callus induction rate gradually decreased.3. Sucrose concentration:5% sucrose in medium caused the highest callus induction rate(75.93%). With further increasing sucrose concentration, the callus induction rate decreased.4. In the anther callus culture, the total phenolic contents and the activity of PPO were positively correlated with the degree of browning. The browning callus and non browning callus had a opposite trend of POD activity, and degree of browning without obvious correlation. The SOD activity was negatively correlated with the degree of browning of callus.5. The most suitable conditions for anther callus culture were pH5.4, sucrose at 40g/L and agar at 7.5g/L, Under different treatments, the total phenolic contents and PPO activity were positively correlated with browning index, while POD and SOD activity were not significantly correlated.6. When the basic medium was MS added 1.Omg/L NAA and 0.25mg/L 6-BA, the lowest browning index of callus was 28.92%. In this culture condition, the total phenolic contents and activity of PPO were positively correlated with the browning index, POD activity was not correlated with browning index, and SOD activity was negatively correlated with browning index of callus.7. In the experiment of AgNO3, the callus browning index was lowest when the medium was added AgNO3 6mg/L, and the results showed that total phenolic contents and PPO were positively correlated with browning index, POD was no significant correlation with browning index, and SOD was negatively correlated with browning index.8. In the experiments with the different antioxidant treatments, 100mg/L ascorbic acid and 10mg/L citric acid had the best anti-browning effect. With different treatments of ascorbic acid, the total phenolic content and PPO activity were all affected by browning, while POD was not correlated.9. In the experiments with the different adsorbent treatments,1.2g/L activated charcoal and 1.5g/L PVP had the best anti-browning effect. With different treatments of activated charcoal, The browning index was positively correlated with the total phenolic contents, and negatively correlated with SOD activity, and no correlation with POD activity, PPO activity is a factor that causes browning, but not a major factor.