With the continuous development of facilities and horticulture, the area of vegetable planting in facilities increased year by year. Watermelon (Citrullus vulgaris Schrad) as the main cultivars within the facility, the continuous cropping problem is very serious, resulting in continuous cropping obstacles become increasingly obvious, the incidence of fusarium wilt increased year by year. Grafted watermelon roots developed to improve the growth of grafted roots of the conditions, resulting in robust plant growth. At the same time, the use of different purposes of the rootstock can make watermelon in different soil conditions under normal growth, such as the use of low temperature, drought, salt tolerance, barren and other characteristics of the rootstock. Secondly, the rootstock of the strong absorption of water absorption capacity, to promote the growth of grafted watermelon plants strong, large watermelon fruit, high yields. In addition, grafted watermelon seedlings grow fast early, for early maturing cultivation and overcome the seedless watermelon early growth slow defects is extremely favorable. So the use of pumpkin as a watermelon grafting rootstock, can effectively improve the effect of watermelon resistance to Fusarium wilts. And provide the theoretical basis and scientific basis for the further study of photosynthetic characteristics, disease resistance breeding and effective control of watermelon. In this experiment, the watermelon varieties with different resistance to fusarium wilt were selected, and the anti-fusarium wilt watermelon was studied systematically. There are changes in physiological characteristics during growth and development. In conclusion, grafting promotes the growth of watermelon and physiological characteristics of the index rose.

KEYWORDS: watermelon; fusarium wilt; growth period; physiological characteristics

Objective: To study the changes of growth, physiological and absorption characteristics of Pinus bungeana under ozone (O₃) stress, to elucidate the correlations among the indicators, and to determine its degree of response to O₃. Methods: The growth, physiological characteristics and O₃ uptake capacity of Pinus bungeana seedlings were measured in an open-top O₃ fumigation manual control experiment with three concentration gradients (NF: normal atmospheric O₃ concentration, NF40: normal atmospheric O₃ concentration plus 40 nmlol/mol; NF80: normal atmospheric O₃ concentration plus 80 nmol/mol), and the relationships between the characteristics of Pinus bungeana under different O₃ concentrations were investigated with correlation analysis, redundancy analysis and analysis of variance. Results: (1) Plant height growth (ΔH), diameter growth at 50 cm (ΔDBH), stomatal size (S), stomatal density (M), stomatal opening (K), stomatal conductance (G_s), net photosynthetic rate (P_n), transpiration rate (E_t), water use efficiency (WUE), maximum photochemical efficiency (F_v/F_m), chlorophyll content (CHL), whole tree water consumption (W), and O₃ uptake rate () all decreased with the increase of O₃ concentration; while intercellular CO₂ concentration () and relative conductivity (L) increased with the increase of O₃ concentration; (2) growth indicators of Pinus bungeana under O₃ stress (ΔH, ΔDBH) were the most correlated with O₃ uptake status (, W), followed by photosynthetic indicators (, WUE, ,, ) and growth indicators (ΔH, ΔDBH) and stomatal characteristics (K, M, S) under O₃ stress, some physiological indicators (L, ) were relatively weakly correlated with photosynthesis (, WUE,,, ) and stomatal (K, M, S); (3) all the indicators of Pinus bungeana were significantly different under O₃ treatments of NF and NF80 (P < 0.05), ΔH, ΔDBH, M, CHL, , , W and were most significantly different under NF and NF40 treatments, and K, S, WUE, , , , L were more significantly different under NF40 and NF80 treatments. Conclusion: The experiment proved that the growth of Pinus bungeana was slowed, photosynthetic capacity was reduced, and the absorption capacity of O₃ was further reduced by long-term exposure to high concentration of O₃. The growth of Pinus bungeana was most correlated with the changes of O₃ absorption characteristics, and the stomatal characteristics were most correlated with photosynthetic physiological characteristics, and the reduction of photosynthetic capacity etc. further led to the curtailment of its growth.