研究不同水氮对甘肃省河西地区西瓜生育后期生长状况的影响，为西瓜合理栽培提供技术支撑。以西研8号为指示品种，采用田间裂区试验设计，主处理为3个灌水量:分别为田间最大持水量80%、65%、50%，副处理为4个施氮量，分别为施N 0、100、200、300 kg/hm2，对西瓜生育后期伤流液量、可溶性蛋白(SP)、谷氨酰胺合成酶(GS)、硝酸还原酶(NR)、过氧化氢酶(CAT)、过氧化物酶(POD)、根系脱氢酶活性含量及西瓜生长状况进行了检测。结果表明，灌水量为田间最大持水量的80%时施N 200 kg/hm2处理伤流液量最高，为32.04 mg/h；西瓜SP含量最高，为4.62 mg/g；水氮均显著影响西瓜根系脱氢酶活性，田间最大持水量65%处理最大，平均达84.06 μg/(g·h)。GS、NR及根系活力在施N 100、200 kg/hm2处理中随灌水量增加呈先升后降的趋势，且田间最大持水量65%处理最高。综合评价可知，田间最大持水量65%下施N 200 kg/hm2处理西瓜成熟期生长综合评价得分最高，为0.72，西瓜生育后期生长状况最佳，适宜河西地区西瓜品种西研8号的水肥管理。

In order to explore the effects of water and nitrogen coupling on the late stage of growth of watermelon in Hexi region of Gansu Province, Xiyan 8 was used as test material, a field split-plot experiment was conducted with 3 main treatments of 80%, 65% and 50% field capacities, and 4 secondary treatments of N 0 kg/ha, N 100 kg/ha, N 200 kg/ha and N 300 kg/ha nitrogen application rates, and a total of 12 treatments were set up. The amount of wound fluid, soluble protein content(SP), glutamine synthetase(GS), nitrate reductase(NR), catalase (CAT), peroxidase (POD), root dehydrogenase activity and growth status were detected. The results showed that 80% field capacity+N 200 kg/ha had the highest fluid volume (32.04 mg/h) and SP content (4.62 mg/g). Water and nitrogen significantly affected the root dehydrogenase activity of watermelon, and 65% field capacity treatment was the highest with an average of 84.06 μg/(g·h). GS, NR and root activity increased firstly and then decreased with the increase of irrigation amount in N 100 kg/ha and N 200 kg/ha treatments and were both peaked at 65% field capacity. The overall evaluation showed that 65% field capacity+N 200 kg/ha treatments had highest scores of comprehensive evaluation of watermelon growth at maturity stage(0.72), the growth of watermelon in this treatment group was the best at the late stage, which was suitable for Xiyan 8 watermelon cultivation in Hexi region.

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甘肃省农业科学院成果转化项目(2022GAAS-CGZG03)；甘肃省农业科学院条件建设项目(2022GAAS-TJJS04)。