持绿和早衰花生品种根系形态、叶片生理及产量对叶面喷施磷肥的响应

【目的】叶面喷施磷肥是土壤施磷的重要补充,作物品种、喷施浓度等因素都会影响磷的喷施效果。比较不同花生品种喷施磷肥后根系形态、叶片酶活性、养分吸收特性及产量的差异,可加深对品种特性与叶面喷磷效果关系的理解。【方法】在温室大棚内进行沙培盆栽试验,采用两因素试验设计,以持绿型品种花育39和早衰型品种花育20为材料,设置P2O50(对照)、0.1%(P0.1)和0.2%(P0.2)3个叶面喷磷水平,以磷酸二氢钾作为叶面磷源,于初花后第5和15天各喷施1次。结荚初期(播种后70天)和成熟期(播种后110天)分别取新鲜叶片(主茎倒三叶)测定丙二醛(MDA)含量及抗氧化酶活性,取根系鲜样测定根系形态指标,将整株花生分为营养体(根、茎和叶)、果针和荚果三部分烘干后测定干物质重及氮、磷含量。【结果】结荚初期,与对照相比,P0.1处理显著提高了两品种根长、根体积、根表面积,提高叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)及过氧化氢酶(CAT)活性,降低了MDA含量;P0.2处理植株各指标增幅小于P0.1处理,多数与对照差异不显著。成熟期,持绿型品种两喷磷处理(P0.1和P0.2)各指标增幅较小,多数与对照差异不显著;叶面喷磷降低了早衰型品种根系长度、表面积和体积,增加了叶片膜脂过氧化程度,加速了植株衰老,其中P0.2对根系和叶片的负面影响大于P0.1处理。喷施叶面磷肥提高了两品种不同器官及整株的氮、磷积累量,持绿型品种P0.2处理荚果中元素积累量高于P0.1处理,而早衰型品种则表现出相反趋势。叶面喷磷提高了两品种各器官干重及荚果产量,其中持绿型品种P0.2处理整株干重低于P0.1处理,荚果产量高于P0.1处理,虽然早衰型品种P0.2处理的营养体干重高于P0.1处理,但其果针干重和荚果产量均低于P0.1处理。【结论】叶面喷磷对两个品种结荚初期根系发育及叶片生理活性均有促进作用,0.1%P2O5的效果好于0.2%P2O5。成熟期,持绿型品种根系和叶片对叶面磷肥的反应不敏感,但与P0.1相比,P0.2处理荚果中氮、磷元素累积量及荚果产量增幅更大,因此,该品种适宜的叶面喷施磷肥浓度为0.2%P2O5。喷施0.2%P2O5磷肥显著降低了早衰型品种成熟期根系形态指标和叶片生理活性,一定程度上抵消了叶面喷施磷肥对该品种结荚初期的积极作用,导致P0.2处理植株氮、磷积累量及荚果产量的增幅小于P0.1处理。因此,早衰型品种更适合的浓度为0.1%P2O5。

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

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。

Effect of Phosphorus and Potassium Foliar Treatment on Seed Yield and Yield Components of Red Clover （ Trifolium pratense L.） Cultivars

Proper mineral nutrition of red clover especially on the acid soils is a prerequisite for the realization of maximum potential for seed yield. The field experiment with four cultivars of red clover were established on soil having a pH （in H2O） of 4.8, in order to in conditions of dense planting （20 cm inter row） analyzes the effect of foliar application of phosphorus and potassium （PK） on yield and yield components （number of stems/m2, number of inflorescences/m2, number of inflorescences/stem, number of flowers/inflorescence, number of seeds/inflorescence and one thousand grain weight）. Regardless of foliar treatment with PK, varieties differed in the number of inflorescences/m2, number of flowers/inflorescence, number of seeds/inflorescence and seed yield. Foliar application of PK in the phase of intensive growth of red clover had a positive impact on number of stem/m2, number of inflorescences/m2 and seed yield in all varieties, as well as on the number of flowers/inflorescence, number of seeds/inflorescence in cultivar Viola.