钨酸钠对苹果幼苗15N吸收利用、13C积累及果实品质的影响

分别以1年生苹果砧木M9T337幼苗和5年生烟富3/SH6/平邑甜茶为试材,开展盆栽和田间试验,并结合¹⁵N、¹³C同位素示踪技术,研究不同浓度(0、0.5、1、1.5 mmol·L^-1,分别用CK、T₁、T₂和T₃表示)硝酸还原酶(NR)抑制剂钨酸钠对苹果幼苗¹⁵N吸收利用、¹³C积累和成熟期果实品质的影响。结果表明: 盆栽试验中,喷施0.5~1.0 mmol·L^-1钨酸钠可显著抑制幼苗地上部生长,但对根系生长影响不显著;当钨酸钠浓度达到1.5 mmol·L^-1时可显著抑制根系生长。同一时期各处理叶片NR活性与钨酸钠浓度呈负相关,均表现为CK>T₁>T₂>T₃。随处理时间的延长,叶片硝态氮含量总体表现为先升高后降低的趋势,同一时期各处理硝态氮含量与钨酸钠浓度呈正相关,均表现为T₃>T₂>T₁>CK。喷施钨酸钠可不同程度地降低幼苗各器官¹⁵N吸收量和¹⁵N利用率,且钨酸钠浓度越高,抑制幼苗氮素吸收和利用的效果越显著。随钨酸钠浓度的提高,地上部¹³C积累量呈先升高后降低的趋势,在T₂处理时达到最高;幼苗整株¹³C积累量呈相似的规律。田间试验结果表明,喷施钨酸钠可降低成熟期叶片和果实的氮含量,果皮花青苷含量、果实可溶性固形物、可溶性糖含量和糖酸比均不同程度提高,其中T₂处理的效果最好。综上,T₂处理(1.0 mmol·L^-1钨酸钠)可有效抑制幼苗地上部生长,降低¹⁵N吸收利用,提高¹³C积累,有利于果实品质的提高。

Effects of Na2WO4 on 15N absorption and utilization,13C accumulation of apple seedling,and fruit quality

Pot culture and field experiments were carried out with one-year-old apple rootstock M9T337 seedlings and five-year-old ‘Yanfu3’/SH6/M. hupehensis Rehd. as test materials respectively. Combined with ¹⁵N and ¹³C isotope tracer technology, we examined the effects of different concentrations of NR inhibitor Na₂WO₄(0, 0.5, 1, 1.5 mmol·L^-1, expressed by CK, T₁, T₂ and T₃ respectively) on ¹⁵N absorption and ¹³C accumulation of seedling and apple quality. The results showed that 0.5-1.0 mmol·L^-1 Na₂WO₄ significantly inhibited shoot growth but not root growth of seedling in the pot experiment. Root growth was significantly inhibited when the concentration of Na₂WO₄ reached 1.5 mmol·L^-1. The NR activity of each treatment was negatively correlated with the concentrations of Na₂WO₄ in the same period, with an order of CK>T₁>T₂>T₃. The content of nitrate in leaves showed the trend of first rising and then decreasing with the extension of processing time. Nitrate content was positively correlated with Na₂WO₄ concentration in the same period, with an order of T₃>T₂>T₁>CK. Spraying Na₂WO₄ reduced the ¹⁵N absorption of each organ and ¹⁵N utilization rate, with such effects increasing with the amount of spraying. With the increases of Na₂WO₄ concentration, ¹³C accumulation on the ground increased first and then decreased, with highest value in T₂ treatment. The ¹³C accumulation of whole plant showed a similar pattern. The results of field experiment showed that Na₂WO₄ application reduced nitrogen contents of leaves and fruits at maturity stage, and increased the anthocyanin content in peel, soluble solids, soluble sugar content and sugar acid ratio in fruits. The T₂ treatment showed the best effect. In summary, T₂ treatment (1.0 mmol·L^-1 Na₂WO₄) could inhibit shoot growth of seedlings, reduce ¹⁵N absorption and utilization, improve ¹³C accumulation, which would improve apple quality.