花生产量形成期不同磷源利用特点及其基因型间差异机制研究

Roots, leaf-stems, peg-pods of peanut all have the function to absorb the phosphorus (P). During yield forming period, the absorption capacity, allocation proportion of P among organs could affect yield formation, as well as organs senescence which in turn affect the formation of production. China has been facing the dual pressures from lack of P resource and low efficiency of P fertilizer. So it is crucial for improving P efficiency. Based on the previous study on the effect of P to root morphological and physiological characteristics, this study will be conducted along the mainline of P metabolism and the main aim of exploiting P absorbing potentialities of different organs and promoting plant P efficiency. In this study, the partial "split" and overall "portfolio" combining methods based on P sources (deriving from roots, leaves, stems, pegs and pods ) are used to: (1) investigate the P absorbing characteristics, P transportation and distribution rule (including storage P and absorption P), and their contribution to yield formation and impact on nutritive organ senescence under different levels of P application to peanut organs and two genotypes in yield forming period; (2) clarify the compensatory, synergistic and inhibiting effect among organs, and their relations with other physiological metabolism; (3) determine P supplying potential of different P sources and their contribution potential to yield; (4) reveal the P metabolism mechanism between genotypes with different leaf senescence characteristics; (5) point out technological approaches based on collaborative exerting the P uptake potential of roots, leaf-stems, peg-pods, and enhancing the plant P efficiency.

花生根系、叶片及针果均具有吸磷功能，产量形成期各器官吸磷能力及磷在器官间的分配比例，不仅影响着产量的形成，而且对其它器官的衰老速率也有调控作用，这种调控作用反过来又影响着产量形成。我国一直面临着磷资源匮乏与磷肥利用率低的双重压力，提高磷利用效率意义重大。本项目以挖掘不同器官吸磷潜力及提高植株磷效率为目标，在前期研究磷对根系形态及生理特性影响的基础上，以磷代谢为主线，将不同磷源（来自根系、叶茎、针果）采取局部"分割"与整体"组合"相结合方法，在产量形成期对不同器官供磷，研究不同基因型品种磷的吸收特点、运转分配规律（包括贮藏磷和吸收磷）及其对产量形成和营养器官衰老的影响，阐明不同器官间磷的补偿效应、协同效应和相互抑制效应及其与其它生理代谢的关系，明确不同磷源供磷潜力及对产量贡献潜力，揭示不同落叶属性品种磷代谢差异机制，提出基于协同发挥根系、叶茎、针果磷吸收潜力及提高植株磷效率的技术途径。

我国是磷资源匮乏的国家，农业生产承受作物持续增产，磷利用效率低及施磷成本增加的多重压力。提高磷效率意义重大。花生叶片及针果均具有吸磷功能，是根系吸磷的重要补充。本项目研究了不同类型品种及土壤磷水平下，不同“磷源”的吸收、运转和分配规律及其对产量形成和营养器官衰老的影响，探讨了不同“磷源”供磷潜力、器官间补偿效应及对产量贡献潜力。结果表明：（1）与常绿型品种相比，早衰型品种产量形成期茎叶中贮藏磷向生殖体的转移量、转移率及转移磷对产量的贡献率分别高出125.4%、67.5%和120.7%，这种过量的向生殖体转移导致早衰型品种茎叶磷“入不敷出”，进而加速了叶片的衰老，是早衰型品种后期叶片加速脱落的生理机制，因此，叶面追磷是延缓早衰型品种早衰的有效途径之一；常绿型品种对叶面磷肥的吸收能力和磷肥浓度的耐受力高于早衰型，且磷分配也存在差异，前者对叶面磷肥的吸收率较后者高3.3~3.7个百分点，磷更多的分配到生殖体（籽仁和果壳）中，适宜的叶面磷肥（磷酸二氢钾）浓度为 0.2%，而后者更多的分配到营养体（根、茎和叶），适宜的浓度为0.1%，表明叶面喷施磷肥对维持早衰型营养体活力、延缓后期早衰作用显著，即叶面磷肥对不同类型品种增产机理不同。（2）土壤磷胁迫时，叶面追磷可显著促进根系和根瘤生长，提高叶片生理活性，增加氮磷养分累积。高浓度（0.2%）的增产效果好于低浓度（P 0.1%），对产量贡献率为6.6%~14.3%，补偿率为145.5%~333.3%。而土壤磷充足时，花生对叶面磷肥吸收率较土壤磷胁迫时降低13.2个百分点，低浓度效果好于高浓度。（3）针果供磷能够促进根系生长发育。根系层磷胁迫时，针果供磷主要用于荚果，对产量的贡献率达8.9%~15.1%，补偿率达16.7%~33.0%，远低于叶片的补偿效应。综上，花生生产中应根据土壤磷水平和品种特性，选择适宜浓度叶面磷肥，并适当调整根系层和结果层的施磷比例，充分发挥叶片和针果的吸磷潜力。研究结果为花生磷营养调控及高效施磷提供依据。