玉米/花生间作功能叶片光合适应的生理生化及分子机制

Maize intercropped with peanut(maize/peanut) can improve peanut iron nutrient, and realized light complementary use of maize to strong light, peanut to low light. However, the net photosynthetic rate of intercropping peanut was decreased during the later coexistence stage, which affects interspecific complementary bewteen maize and peanut. In our study, different root separation methods will be used in maize/peanut intercropping system to disclose the effects of interspecific rhizosphere nutrition complementary on light reaction system performance and carboxylation reaction system performance of functional leaves. The relationship between above-ground or below-ground interspecific interaction and photosynthetic characteritics of funcational leaves will be illustrated, and the key factors of enhancing the utilization of strong light for maize, and low light for peanut in maize/peanut intercropping will be found. The treatments of different intercropping maize sowing date and the rows ratio of intercropping maize and intercropping peanut will be conducted to investigate the funcational leaves characteristics light absorption, transmission, transformation, CO2 fixing, photosynthetic carbon assimilation enzyme activity, and their response to different light control, respectively. This will aid elucidating physiological and biochemical mechanism that intercropping heightens maize photosynthetic funcation and lowers peanut net photosynthetic rate during the later coexistence stage. Different protein synthesised in maize/peanut intercropping system will be screened on the molecular level and molecular mechnism of fuanctional leaves photosynthetic adaptation reaponse to chemical regulator and phosphate fertilizer will be revealed. .The study will have great theory values of enriching intercropping principles, eapecially in the interspecific complement and light energy utilization among maize/peanut system and benefitting to formulate key cultivational measures of implementing high yield and high effeciency in practice.

玉米/花生间作改善花生铁营养，实现了玉米对强光、花生对弱光的互补利用，但共处后期花生光合速率降低，抑制了种间互补效应。本项目采用不同根系分隔方法，研究玉米/花生间作种间根际营养效应对功能叶片光反应系统性能和羧化反应系统性能的影响，明确玉米/花生间作地下、地上种间效应与光合特性的关系，阐明间作提高玉米对强光、花生对弱光利用能力的关键因素；调节间作玉米播期和间作行比，分别研究间作花生、间作玉米功能叶片光能吸收、传递、转化、CO2羧化固定和光合碳同化酶活性的变化特点及其对光调控措施的响应，阐明间作提高玉米光合功能和共处后期花生光合速率下降的生理生化机制；从蛋白质合成分子水平揭示玉米/花生间作功能叶片光合适应对化学调控和磷肥响应的分子机制。.该研究对发挥玉米/花生间作种间互补效应，提高光能利用效率，提升间套作理论具有重要意义；在生产上，明确玉米/花生间作的关键栽培措施，实现高产高效具有重要应用价值

玉米‖花生间作改善花生铁营养，实现玉米对强光、花生对弱光的互补利用，但共处后期花生光合速率降低，抑制了种间互补效应。为了明确花生光合降低限制因素，协调种间竞争，提高玉米对强光、花生对弱光利用能力，本项目采用根系分隔法和iTRAQ技术，研究了玉米‖花生间作功能叶片光合适应的生理生化及分子机制。主要结果如下：.（1）地上、地下种间作用显著影响作物光合作用。地上、地下种间作用对玉米净光合速率(Pn)、光饱和时最大净光合速率(LSPn)、羧化效率(CE)、Rubisco最大羧化速率(Vcmax)、最大电子传递速率(Jmax)、磷酸丙糖利用速率(TPU)及对铁与氮吸收的贡献为正效应，对花生ΦPSII和表观量子效率(AQY)为正效应，地下种间作用对花生Pn、LSP、LSPn和铁与氮的贡献为正效应, 地上作用则为负效应。可见, 玉米‖花生间作优势来源于地上、地下种间共同作用, 地下种间铁氮效应促进花生光合，但地上光竞争降低花生光合，主要在于抑制了CO2羧化固定能力，地上、地下种间作用均促进玉米光合，且地上作用大于地下。.（2）大口期至灌浆期，间作玉米穗位叶的SPAD值、AQY、LSP、LSPn、CE、Jmax、TPU、气孔导度(gs)、蒸腾速率(Tr)和Pn均表现随着光强增强而提高，胞间CO2浓度(Ci) 则反之；蜡熟期后2:8间作玉米的AQY、LSPn、gs、CE、Jmax和TPU均低于2:4间作玉米；间作花生对弱光的利用能力随着光强减弱逐渐增加，但遮阴超过一定程度而下降。施磷提高间作玉米、花生的AQY、Pnmax、Vcmax、Jmax和TPUmax，间作优势增加15.5%~112.6%。这说明间作玉米对强光、花生对弱光的适应是个渐进过程，在一定范围促进光能利用；施磷增强玉米对强光、花生对弱光的利用、延缓叶片衰老。.（3）化学调控间作玉米显著协调种间光竞争。化学调控剂改善间作玉米株型，降低株高和叶面积指数，提高PSⅡ的CO2羧化固定能力，缩短高光合功能期；增加间作花生冠层光照强度，提高花生CO2羧化固定能力和光合速率；间作优势提高5.8%~7.1%；施磷促进间作玉米、间作花生光合，提高产量。.（4）与单作相比，不施磷间作玉米功能叶的磷酸烯醇式丙酮酸羧化酶(PEPCK)、PSI反应中心亚基V、PSII 11 kD蛋白和脂类相关蛋白2等表达显著上调，施磷间作玉米的果糖二磷酸醛缩酶蛋