| Apple Rootstock 31 is an excellent line selected by in-situ resistance breeding.In this experiment,the two-year-old tissue culture seedlings of rootstock 31 and M.hupehensis Rehd were used as experimental materials.After transplanting,the pot experiment was carried out to determine the morphological and physiological and biochemical indexes of the two rootstocks under different stress,and the drought resistance,salt tolerance,cold resistance and waterlogging resistance of excellent line 31 were preliminarily evaluated,Provide technical support for its extensive regional test in the main apple producing areas.The results are as follows:Under drought stress,the ground diameter of rootstock M.hupehensis Rehd showed significant difference from the 14th day,while the ground diameter of rootstock 31 showed significant difference from the 28th day;The Pn,Tr and Gs of the two rootstocks were significantly lower than those of their normal treatment from 7 days.Under moderate drought stress,the Pn of the two rootstocks decreased to the lowest on 35 days.The Pn of rootstock31 was significantly lower than that of normal treatment by 86.38%,and that of rootstock M.hupehensis Rehd was significantly lower than that of normal treatment by 91.93%;During the whole stress process,the activities of SOD,POD,CAT,MDA and proline increased significantly compared with their normal treatment.Under severe drought stress,the SOD activities of the two rootstocks reached the peak on the 21st day of treatment,the activities of rootstock 31 increased significantly by 141.27%compared with the normal treatment,and the activities of rootstock M.hupehensis Rehd increased significantly by 117.59%compared with the normal treatment,After 35 days of treatment,the SOD activity of rootstock M.hupehensis Rehd was significantly lower than that of normal treatment.Under salt stress,the Na+content and K+content of the two rootstocks increased significantly compared with the normal treatment,and K+/Na+decreased with the extension of stress time,reaching the lowest at 35 days.Under the treatment of 100mmol/L and200mmol/L,the K+/Na+of rootstock 31 decreased significantly by 12.62%and 49.61%compared with the normal treatment,and the rootstock M.hupehensis Rehd decreased significantly by 48.93%and 62.32%compared with the normal treatment,The decline of rootstock M.hupehensis Rehd treated with two salt concentrations was greater than that of rootstock 31;The plant height,ground diameter and MDA content of rootstock M.hupehensis Rehd showed significant differences between salt concentration treatment and normal treatment at 14 days,while rootstock 31 showed significant differences between salt concentration treatment and normal treatment at 28 days;After salt stress,the antioxidant enzyme activities of the two rootstocks increased in varying degrees.Under 200mmol/L treatment,the SOD activity of rootstock M.hupehensis Rehd reached the peak before rootstock 31.When reaching the peak,the SOD activity increment of rootstock 31 was99.24%,and that of rootstock M.hupehensis Rehd was 89.79%.After the peak,the SOD activity of rootstock M.hupehensis Rehd decreased;The Pn,Tr and Gs of the two rootstocks showed a gradual downward trend with the extension of treatment time.After treatment with200mmol/L for 35 days,the Pn,Tr and Gs of rootstock 31 were significantly lower than those of normal treatment by 74.30%,63.11%and 83.88%,and the Pn,Tr and Gs of rootstock M.hupehensis Rehd were significantly lower than those of normal treatment by 90.68%,73.33%and 87.80%.From the perspective of Pn,Tr and Gs,the decline of rootstock M.hupehensis Rehd was greater than that of rootstock 31.Under low temperature stress,the relative conductivity of the two rootstocks increased significantly from-20℃to-40℃compared with 4℃respectively.Under-30℃treatment,the relative conductivity of rootstock 31 and rootstock M.hupehensis Rehd increased significantly by 48.57%and 53.49%compared with 4℃respectively,and the relative conductivity of rootstock 31 was always lower than that of rootstock M.hupehensis Rehd during the whole stress period;The activities of SOD,POD and proline of the two rootstocks showed an"increase decrease"trend with the decrease of temperature.At the peak,the activities of SOD and POD of rootstock 31 increased significantly by 80.48%and 34.60%compared with its treatment at 4℃,and the activities of SOD and POD of rootstock M.hupehensis Rehd increased significantly by 66.40%and 29.39%compared with its treatment at 4℃.Under waterlogging stress,the plant height and ground diameter of rootstock 31 were significantly lower than those of normal treatment from 21 days,the plant height of rootstock M.hupehensis Rehd was higher than that of treatment for 28 days,and the ground diameter was significantly lower than that of normal treatment from 35 days;The SOD activity of rootstock 31 and rootstock M.hupehensis Rehd increased significantly by 46.40%and 55.56%compared with normal treatment,and the increase of SOD activity of rootstock 31 was less than that of M.hupehensis Rehd;The MDA content of rootstock 31 and rootstock M.hupehensis Rehd increased significantly by 112.50%and 75.00%respectively;The Pn,Tr,Gs and root activity of the two rootstocks showed a downward trend with the extension of stress time.At 35 days,the Pn of rootstock 31 and rootstock M.hupehensis Rehd decreased by85.14%and 71.43%respectively compared with their normal treatment,and the root activity decreased by 74.72%and 47.03%respectively compared with their normal treatment.Based on the performance of rootstock 31 and M.hupehensis Rehd in drought resistance,salt tolerance,cold resistance and waterlogging resistance,rootstock 31 is superior to M.hupehensis Rehd in drought resistance,salt tolerance and cold resistance,and inferior to M.hupehensis Rehd in waterlogging resistance,showing strong biological resistance,which is due to its application in Northern semi-arid areas The popularization and application in coastal saline areas and cold areas is of great significance. |
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