| Apple is one of very important fruits in China. Calcium has a very important role in production and storage of apple. Study calcium of Apple in the past mainly on the morphology and cellular, the research of Ca2+/H+Antiporter of apple has not been reported in the moment. In this research, we studyed calcium concentration in fruit and leaf of Nagafu 6'apple; Ca2+/H+ antiporter activity in plasma and tonoplast. We also researched the expression of MdCAX1 gene in defferent parts of Malus robusta seedlings. All those researches would help improve the quality of apple in the future. The results were as follows:1. The experiment was carried out with the 'Nagafu 6' apple for studying concentration of calcium. The results showed that calcium concentration of leaf was increased in whole time, but in fruit calcium concentration was declined and its curve was just like a reversed "j". Calcium concentration in leaf is obviously higher than in fruit. In different parts of apple, calcium concentration in seed was the highest, and peel was secondly. Pulp and core were more less than peel and seed; and calcium concentration between them have a significantly difference. By treatment with calcium with 15min, calcium concentration of seed and peel was increased remarkably, while pulp and core was increased just a little; and calcium concentration between them still have a significantly difference.2. The experiment was carried out with the 'Nagafu 6' apple for studying Ca+/H+ antiporter activity in different times of apple. The plasma was isolated from leaf and fruit by using two-phase partitioning in aqueous dextran T-500 and polyethylene glycol, and tonoplast was isolated by using sucrose gradient. The purity of plasma and tonoplast were 80% and 40% respectively, which met the research. Ca2+/H+ antiporter activity was studied by the filtration method using 45Ca2+. The results showed that Ca2+/H+ antiporter activity on plasma of fruit was increased in whole time, and was the highest at the time after two month of the begging of blooming; and on plasma in leaf Ca2+/H+ antiporter activity was higher at one week and two month after the begging of blooming than at other times. While on tonoplast Ca2+/H+ antiporter activity of fruit and leaf increased firstly and then decreased, at the time after one month of the beginning of blooming was the highest, and at this time, Ca2+/H+ antiporter activity of fruit is 4 times of leaf.3. The experiment was carried out with the 'Nagafu 6' apple fruit for studying Ca2+/H+ antiporter activity in different parts of apple by calcium treatment. The result showed that on plasma Ca2+/H+ antiporter activity was highest in seed, followed by core, peel and pulp, and Ca2+/H+ antiporter activity between them have a significantly difference. While on tonoplast the highest was in peel, followed by seed, pulp and core, Ca2+/H+ antiporter activity between them have a significantly difference. But by the treatment of calcium, the Ca2+/H+ antiporter activity on tonoplast was declined markedly in all parts of apple.4. In order to study the expression characteristics of MdCAXl gene, we treated Malus robusta seedlings by different concertration of calcuim (with 0%,0.5%,1.2% of CaCl2) to study in high calcium and low calcium MdCAX1 gene expression. The results showed that the time to treating apple various, then MdCAXl gene expression varies; treatment with one day, MdCAXl expressed mainly in the stem. Treatment with three-days, seven days, and 12 days later, stem and leaf all have a higher expression of MdCAXl gene. To deal with different calcium concentrations showed that MdCAXl gene expression varied, and dealing with various concentrations of calcium at a certain time can have a higher expression. Treatment with water as control, MdCAXl gene has the highest expression when dealing with three days; Treatment with 0.5% concentration of calcium, MdCAXl gene has the highest expression when dealing with one day and twelve days; Treatment with 1.2% concentration of calcium, MdCAXl gene has the highest expression when dealing with seven days. Study the expression in different parts of seedling have shown that MdCAXl gene expressed little in root, and more in stem and leaf. |
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