土壤施磷与叶面追肥互作对花生根系形态、结瘤特性及氮代谢的影响

Effects of interaction of phosphorus(P) application in soil and leaves on root,nodule characteristics and nitrogen(N) metabolism in peanut

叶面追磷是土壤施磷的重要补充。为明确不同土壤磷水平下花生适宜的叶面追磷浓度,本研究采用营养液沙培试验,研究了土壤充足供磷(P2O5浓度为7.1 mg L^-1,PA)及磷胁迫(P2O5浓度为0.71 mg L^-1,PD)时,不同浓度叶面磷肥(P2O50、0.1%和0.2%,简称CK、P0.1%和P0.2%处理)对花生根系形态、结瘤特性、叶片氮代谢酶及干物质重的影响。结果表明:(1)结荚期和饱果期,叶面追磷能够促进2种土壤供磷水平下花生根系和根瘤生长,提高叶片氮代谢关键酶活性,P 0.2%处理各指标增幅高于P 0.1%处理。收获期,土壤充足供磷时,高浓度叶面磷肥(P 0.2%)导致花生早衰,表现为P 0.2%处理根系、根瘤及氮代谢酶相关指标均低于P 0.1%处理。而土壤磷胁迫时,2种浓度叶面磷肥均能提高上述指标,P 0.2%处理下各指标与P 0.1%处理相当或略高于P 0.1%处理。(2)2种浓度叶面磷肥均能提高花生各器官氮、磷积累量及干物质重。土壤充足供磷时,P 0.1%处理的荚果氮、磷积累量及干物质重增幅大于P 0.2%处理,其他器官(根、茎、叶及果针)各指标则表现出相反趋势。土壤磷胁迫时,各指标均随叶面磷肥浓度增加而增加。追施叶面磷肥增产的主要原因是增加了单株果数。综上,土壤充足供磷及磷胁迫时,花生适宜的叶面追磷浓度分别为0.1%和0.2%。生产上应根据土壤供磷水平,选择适当浓度叶面磷肥。

Spraying P fertilizer is an important supplement for applying P fertilizer in soil.A pot experiment with nutrient solution was conducted to study effect of foliar fertilizer with different P contents on peanut root morphology,nodule characteristics,leaf N metabolic enzymes and dry weight of plant under adequate and stress P conditions,respectively.In pod setting and fulling stages,spraying P fertilizer improved growth of root and nodule,and enhanced activities of N metabolic enzymes in leaves.The increments of each parameter under P 0.2%treatment were larger than those under P 0.1%.In harvest stage,relevant parameters of peanut root,nodule and N metabolism in P 0.2%treatment were lower than those in P 0.1%treatment with adequate soil P.High foliar P fertilizer resulted in senescence of plant.Foliage spray with each of two P contents could improve the parameters mentioned above under soil P stress condition.The parameters of P 0.2%treatment were equal to or a little higher than those of P 0.1%treatment.Foliar P fertilizer increased N,P accumulations and dry weight of different organs.Under adequate soil P condition,the increments of pod N,P accumulations and dry weight in P 0.1%treatment were larger than those in P 0.2%treatment,and the response of the parameters in others parts(root,stem,leaf and peg)to foliar P fertilizer was adverse.Under P stress condition,the parameters increased with increasing foliar P-level.The reason of yield increase in spraying P fertilizer treatments was the improvement of pod number per plant.In conclusion,the suitable foliar P content under adequate soil P and stress conditions is 0.1%and 0.2%respectively.In peanut production,we should choose suitable content of foliar P fertilizer according to soil P level.