嫁接和施氮量对冬瓜干物质、氮素积累及其氮代谢酶的影响

本研究通过开展嫁接栽培与施氮量对冬瓜干物质、氮素累积及其氮代谢酶的影响,明确冬瓜干物质、氮素积累动态规律和氮素吸收利用规律,旨在为冬瓜科学施肥提供理论依据.试验以'铁柱2号'冬瓜和'海砧1号'砧木为材料,试验为裂区设计,主区为栽培方式,分别为嫁接栽培和自根栽培2种栽培方式;副区为氮肥施用量,分别设置N0(0 kg/hm...

Effects of Grafting and Nitrogen Rate on Nitrogen and Dry Matter Accumulation and Nitrogen Metabolism Enzymes in Wax Gourd

The effects of grafting cultivation and nitrogen rates on nitrogen and dry matter accumulation and nitrogen metabolism enzymes of wax gourd were studied to elucidate the dynamic rule of dry matter and nitrogen accumulation and provide theoretical basis for the scientific fertilization of wax gourd. In this study, ‘Tiezhu No. 2’ wax gourd and ‘Haizhen No. 1’ rootstock were used as the materials. A split-plot experiment design was used with cultivation patterns worked as the primary plot, including grafting cultivation and self-root cultivation, and nitrogen rate as the secondary plot, including N₀ (0 kg/hm ²), N₁₈₀ (180 kg/hm²), N₃₆₀ (360 kg/hm²) and N₅₄₀ (540 kg/hm²). The accumulation of nitrogen and dry matter and activity of nitrogen metabolism enzymes for wax gourd in five different growth stages were studied. The total accumulation amount of nitrogen and dry matter first increased and then decreased with the increase of nitrogen application rate with peak values at N₃₆₀, whose nitrogen and dry matter accumulation were significantly higher than those of the other three nitrogen rate treatments. The average nitrogen and dry matter accumulation of grafted wax gourd was 16.11% and 11.76% higher than those of self-rooted wax gourd, respectively in the whole growth period. The maximum theoretical value (K), maximum accumulation rate (V_max), average accumulation rate (V_mean), the beginning period of rapid accumulation period (T₁), the ending period of rapid accumulation period (T₂) and the occurrence time of maximum accumulation rate (T_max) of nitrogen and dry matter accumulation of wax gourd increased first and then decreased with the increase of nitrogen rate with peak values at N₃₆₀. While K, V_max) and Vmean of nitrogen and dry matter accumulations in grafted wax gourd were higher than those of self-rooted wax gourd. The activity of nitrate reductase (NR) and glutamine synthetase (GS) increased first and then decreased with the growth period proceeded, and reached the maximum at 75 days. The activity of NR and GS increased first and then decreased with the increase of nitrogen application rate, with peak value at N₃₆₀, the activity of NR and GS was significantly higher than those at N₀, N₁₈₀ and N₅₄₀. Compared with self-rooted wax gourd, the NR activitiy of grafted wax gourd increased by 33.08%, 28.95%, 34.63%, 36.03% and 67.23% at 30 days (vine extension stage), 55 days (flowering stage), 75 days (early fruit development stage), 95 days (middle and late fruit development stage) and 110 days (mature stage), with GS increased by 29.64%, 22.11%, 21.00%, 28.00% and 35.27%, respectively. In conclusions, grafting can significantly improve the accumulation and the rate of dry matter and nitrogen and the activity of NR and GS. N₃₆₀ was the optimum nitrogen application rate for wax gourd in production.