| Blossom-end rot (BER), a kind of physiological diseases in the production of tomato, has a significant impact on the quality and the yield of greenhouse tomato. It is generally believed that the calcium deficiency of tomato fruit is the main reason for the BER, and the incidence of BER is obvious differences among different varieties. Therefore, it is significant to explore the relationship among different tomato varieties on the resistance of BER and the use of calcium for clearing the BER mechanism under calcium deficiency. In this paper 50 Lycopersicon pennellii introgression lines were selected as experimental material by soilless culture under the calcium deficiency. We studied the effect of low calcium hydroponic culture on calcium content in different parts of fruit along with the date from young to ripe during the fruit growing season and calcium absorption in the root system and photosynthesis in leaf during the seedling stage, The main results are as follows:1.50 Lycopersicon pennellii introgression lines planted on rock wool were cultured with modified Yamazaki nutrient solution of low calcium concentration. The resistant lines and susceptible lines were screened by the fruit total calcium content and the incidence of BER rate. The results showed that the incidence of BER in 1-3 lines and 5-4 lines was 48.1% and 28.3% on low calcium treatment, while, the incidence of BER in 4-2 lines and 8-3 lines was zero under low calcium treatment. The reduce rate of total calcium content between low calcium treatment and normal calcium treatment were differ on each lines,1-3 was 40.2% and 5-4 was 50.3%, but 4-2 was 11.0% and 8-3 was 2.7%. The test showed that the incidence of blossom-end rot related to the calcium content of the fruit and 1-3 was the susceptible lines and 8-3 was the resistant lines for BER.2. M82、1-3 and 8-3 were cultivated with low calcium nutrient solution, the incidence of BER was investigated, and the total calcium content of blossom end part, middle part and shouder part was tested from 10 days to 50 days after fruit setting. The results indicated that the 10 days fruits is easier to get BER. The total calcium content in blossom end part and the middle part was low, but it was high in shoulder. A higher incidence of BER was showed in 1-3, the low calcium treatment was 63.7% and the control was 50.1%, but it was zero incidence rate of BER in 8-3 lines. The total calcium content of blossom end part and middle part in 1-3 was lower than that in 8-3. It was 35.2% under low calcium treatment and 62.1% under normal calcium treatment on blossom end parts. While it was 23.4% under low calcium treatment and 47.2% under normal calcium treatment on middle parts. So it was the lower calcium content in blossom end of 1-3 cause the high rate of BER.3. The BER fruit and normal fruit of DR5:GUS hydroponiced with low calcium were tested for total calcium, total potassium and total magnesium content. The current speed of Ca2+was measured by Non-invasive Micro-test Technology. The results indicated that total calcium content of BER fruit was decreased, total potassium and magnesium content relative with total calcium increased; The current speed of calcium showed absorption on the epidermis of young fruit of tomato BER and the surface of the placenta and core measured by NMT, which from blossom end part to the fruit shoulder increased gradually, but the normal fruit was no significant. The results showed that the low calcium content of fruit and poor ability of fruit cell absorb the calcium lead to BER.4. Tomato seedlings of M82,1-3,8-3 were hydroponiced with low calcium and measured the photosynthetic and fluorescence value during the days under the treatment and the relative quantitation of Ca2+-ATPase and H+-ATPase genes were measured during the days under the stress of low calcium. The net photosynthetic rate、transpiration rate、stomatal conductance、 international carbon dioxide concentrations and maximal photochemistry efficiency of leaves decrease significantly,8-3 returned to normal after calcium recovery,1-3 and M82 were failed. The relative quantitation expression of Ca2+-ATPase and H+-ATPase genes in root tip and tender leaves increased and was the highest in 8-3. So,8-3 showed the ability on absorb calcium and low calcium resistance. |
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