豫西高山夏季番茄育苗温度适宜度定量评价

高温是夏季蔬菜育苗的主要障碍因子,利用高海拔地区夏季气候冷凉优势,发展适地育苗是优化蔬菜种苗基地布局的重要方向。为了科学利用高山夏季气候优势,探明夏季高山育苗的温度适宜性及对幼苗生长的影响,该文以番茄为试材,于2016、2017两个年度,分别于高海拔(海拔998 m)和平原地区(海拔98 m)的同一类型的塑料大棚内进行了4茬育苗试验。运用温度适宜度模型和游程理论对温度特征进行了定量分析,探讨了气温和根际温度适宜度与番茄幼苗生长的关系。结果表明:夏季高山育苗设施内气温和根际的夜间均温比平原分别低了16.14%、18.99%,差异达极显著水平。育苗期间高山温度适宜度为163.64%(白天+夜间+根际),是平原的2.23倍;不适宜度为13.34%(白天+夜间+根际),比平原降低了88.73%。播后28 d,高山番茄幼苗全株干物质积累量是平原的1.39倍,壮苗指数是平原的1.34倍,可溶性糖含量比平原高37.91%,根系活力比平原提高了65.42%。白天温度适宜度与幼苗干物质(r=0.774)及地上干质量(r=0.773)的积累量,夜间温度适宜度与根冠比(r=0.934)及地下干物质(r=0.808)的积累量相关性均达极显著水平。高山培育的番茄幼苗定植后开花节位显著减低,开花数、坐果数和坐果率显著增加。综上,夏季利用高海拔地区气候冷凉优势是培育蔬菜壮苗的有效的途径,该研究为高海拔地区夏季开展蔬菜集约化育苗提供了参考。

Quantitative assessment of temperature suitability of alpine summer tomato seedling in west of Henan province

Heat stress is well recognized as a major biotic stress that severely limits plant growth worldwide. In particular, high temperature is a main limiting factor in the production of vegetable industrialized seedlings raising in summer. Optimal and stable temperature is an important factor for plant growth and metabolism. Tomato is thermophilic, but it cannot withstand high temperature. Hence, how to lower the temperature is an urgently problem that needed to be solved. The low temperature at high altitude localities provided an opportunity to develop the vegetable industrialized seedlings raising production in summer. Raising vegetable seedlings at high altitude is more economical compared with some cooling methods (e.g., forced ventilation, fan/pad system, mist/fog system, roof cooling, mechanical cooling technology system, aquifer coupled cavity flow heat exchanger system, and earth-to-air heat exchanger system) depending on energy consumption. Furthermore, it also provided a new direction to select a suitable location for vegetable industrialized seedlings raising. The objective of this study was to investigate the temperature suitability of the summer alpine seedlings and the effects of high-altitude temperature on tomato seedling growth. During 2016 and 2017, several experiments were performed within four cropping seasons using tomato (Solanum lycopersicum L. Roller) seedlings in the same type of plastic greenhouses at two altitudes, respectively at high (998 m) and low (98 m). Then, temperatures of the alp and plain were measured during tomato seedlings growth. In addition, temperature characteristics were analyzed using the temperature suitability model and run-length theory. Finally, the relationship between air and root-zone temperature and tomato seedling growth were determined by path analysis. In summary, the results showed that the average air and root-zone temperature of night at high altitude significantly (P<0.05) decreased by 16.14% and 18.99%, respectively, in comparison to the plain. More importantly, the average duration of daily maximum temperature decreased by 7.74h at alpine greenhouse in comparison to plain greenhouse. Consequently, raising tomato seedlings at alpine greatly alleviated the damage of high temperature on seedlings. The temperature suitability and temperature unsuitability were 163.64% (daytime+nighttime+root-zone) and 13.34% (daytime+nighttime+root-zone) at high altitudes, which increased by 2.23-fold and decreased by 88.73%, respectively, in comparison to the plain. Furthermore, compared to the plain, the whole plant dry weight, and the seedling healthy index of 28-days-old tomato seedlings growth at high altitude were significantly (P<0.05) increased by 1.39-fold, 1.34-fold, respectively, the soluble sugar content and root vigor significantly (P<0.05) increased by 37.91% and 65.42%, respectively. The day temperature suitability had an extremely significant correlation with the plant dry weight (r=0.774) and shoot dry weight (r=0.773).The night temperature suitability had extremely significant correlation with the root/shoot ratio (r=0.934) and root dry weight (r=0.808), respectively. Compared with the plain, tomato seedlings grown at high altitude had a significant lower flowering node position, and increased numbers of flowers, fruit and fruit set rate after transplanting. In conclusion, this study indicated that raising tomato seedlings at high altitude is an effective method to alleviate high temperature stress and promote tomato seedling growth during summer season.