Effect Of Low Temperature And Poor Light On Growth And Development Of Eggplant In Solar Greenhouse

Eggplant(Solarium melongena L) is one of the most important vegetables cultivated indoor in north China. The cold weather in early spring in the northern area has big influence on the indoor cultivated vegetables. This experiment focus on the influence of different low temperatures and light level conditions on the growth, root system vatality, photosynthesis, antioxidant enzyme activity of Tianfeng Youguan variety, Quanxing purple round eggplant and Ha eggplant2012and black eggplant. By studying the adaptation system of eggpalnt plants to low temperatures and low light levels we try to provide theoretical basis for the cultivation of eggplant and low temperature endurance and low light level eggplant breeding.1. Under low temperature and poor light level(Temperature:21-23℃, illumination intensity set as75%of the compared sample) for7days, the plant height, stem diameter and leaf area growth were restrained to different extent. As time went on(14days) and temperature keep lowering(18-20℃) and weakening of light(50%of the compared sample), we find more evident restrained aspects mentioned and more distinct differences between the different treatments. By recovering these factors, the eggplant treated by extreme low temperature and low light level is difficult to recover back to normal growing conditions while by weaker treatment it can recover to normal conditions.The root system vitality study under low temperatures and low light levels. Treatment2(Temperature:18-20℃, Illumination intensity as50%of the compared sample), the root system vitality of eggplant decrease greatly, in which Tianfeng Youguan variety decreased72.8%. Through variance analysis the Tianfeng Youguan variety shows greater average difference to every treatment. Other varieties show greater difference in treatment1and3, treatment1and treatment2.After treatment for14days, the root system vitality of Tianfeng Youguan variety in the different eggplant varieties shows greater decrease, about83.5%. Through variance analysis it shows greater differences to every treatment. During recovery, Tianfeng Youguan and Qunxing purple round eggplant recover their normal root system vitality in7days, while for Ha eggplant2018and Black eggplant they did not recover in21days, which shows the root system vitality of Tianfeng Youguan and Quanxing purple round eggplants are stronger than the other two varieties.2.Under low temperatures and low light level for14days, for treatment2and treatment3the increase of MDA content in Tianfeng Youguan among these varieties is the largest. During later stage of recovery, in treatment2and3the MDA content did not have big change in other varieties. In treatment1Tianfeng Youguan and Qunxing Purple Round eggplant affected by the outside weather conditions, while for Ha eggplant2018and Black eggplant show little impaction. the MDA content of these varieties are able to back to the level in treatment1and Tianfeng Youguan is the fastest.3. After low temperature and low light level treatment, the SOD enzyme activity of eggplant sprouts of every treatment get lower, by lowering temperature and light level furtherly, the decrease of enzyme activity becomes evident. On the7day of recovery(the21st day) the SOD enzyme activity show high level in the eggplant sprout leave in every treatment. On the28th day and35th day, the SOD enzyme activity of Tianfeng Youguan, Qunxing Purple Round Eggplant and Ha Eggplant2018shows big difference, maybe affected by the weather condition. Black eggplant shows little difference, maybe affected little by the late stage low temperature and light level.4. Continual treatment for7days under two conditions:Treatment2:18-20℃, light intensity as50%of treatment1; Treatment3::21-23℃, light intensity as75%of treatment1, the Proline content in the four varieties of eggplant leaf increased, treatment2>treatment3. As time goes by, the increase of Proline content becomes evident and distinct. After recovery, the Proline content in Tianfeng Youguan variety did not have significant change and for other varieties decrease greatly.Soluble sugar content in two conditions change greatly. Soluble protein content change is not regular thus need further study.5. The net photosynthesis efficiency, transpiration rate, intercellular CO2density and stomatal conductance of plants in treatment2has distinct change and have significant difference with the compared sample. The photosynthesis features change of these varieties in treatment3is small and have significant difference with compared sample. During late stage of recovery the photosynthesis aspects recover to the level of the compared sample while the other varieties did not.6. The experiment shows, the yield of plants were affected in different degree after low temperature and low light level treatment. Treatment2has great influence in the soluble sugar content, soluble protein content, organic acid content and Vitamin C content and yield in the fruits of every variety. Treatment3has little influence of these aspects, quite different with the compared sample. The yield of eggplant in treatment3is not affected greatly and the difference with sample is not big, but the low temperature and low light level affected the actual picking time and commercial efficiency.