EFFECTS OF DIFFERENT SUPPLEMENTAL LIGHT MODES ON THE BIOCHEMICAL ELEMENTS SYNTHESIS AND QUALITY OF TOMATO SEEDLINGS IN GREENHOUSE

Improving crop light environment can not only increase crop biomass accumulation, but also affect crop yield and quality. Therefore, exploring the light environment requirements of different crops has always been a research hotspot in the field of facility horticulture. In this paper, taking a region with short light time in western China as an example, the effect of leaf back light supplementation on the quality of greenhouse tomatoes was systematically studied. The results of the study show that according to the light intensity in the western region and the growth habit of tomatoes, it is necessary to properly supplement the light of greenhouse tomatoes. The net photosynthetic rate (P-a) of tomato leaves under supplemental light treatment was significantly higher than that of the control. During the test time, the change trend of Pn-PPFD is the same as that of P-n. Under the E1 treatment, the maximum Pn of the leaves under the saturated light intensity was the highest, which increased by 63.4% compared with the control; followed by E2 and E3, with an increase of close to 42.8%. Foliar spraying of exogenous calcium can increase crop yield and improve quality. Calcium not only promotes the growth and development of crops, but also improves the quality of crops by improving the absorption of mineral nutrients by plants. There is an interaction effect between different light supplement modes and calcium, and the effect of low concentration calcium fertilizer on fruit morphology and quality is better than that of high-concentration calcium fertilizer. Under different photoperiod conditions, exogenous Fe fertilizer has a promoting effect on the photosynthetic characteristics and fruit quality of tomato leaves, and the effect of spraying 145 mon Fe fertilizer on leaves under 16h/8h photoperiod is the best. This research can provide technical support for the high-yield and high-quality production of vegetables in areas with short sunlight hours in western China.