To clarify the photosynthetic mechanism contributing to the enhancement of intercropping advantages through co-ridge intercropping of maize and peanut, we conducted a field randomized block experiment under two phosphorus levels of 0(P0) and 180 kg P2O5·hm-2(P180) with flat intercropping of maize and peanut (FIC) as the control. We analyzed the effects of co-ridge intercropping of maize and peanut (RIC) and groove-ridge intercropping of maize and peanut (GIC) on crop leaf area index (LAI), SPAD values, CO2 carboxylation ability, photosystems coordination (ΦPSⅠ/PSⅡ), and intercropping advantage of yield. The results showed that RIC significantly increased SPAD value at the silking stage of intercropping maize, and significantly improved the apparent quantum yield of photosynthesis (AQY), maximum electron transfer rate (Jmax), maximum rate of Rubisco carboxylation (Vc,max), net photosynthetic rate at the CO2 saturation (Amax) and ΦPSⅠ/PSⅡ of intercropping maize compared with those of FIC and GIC at silking stage and milking stage, but reduced the ratio of variable fluorescence Fk to amplitude Fj-Fo(Wk) and the ratio of variable fluorescence Fj to amplitude Fp-Fo(Vj) of the functional leaf photosystem Ⅱ (PSⅡ) at the milking stage of maize. There were no significant differences in these parameters between FIC and GIC. Compared with FIC, both RIC and GIC increased LAI of intercropping peanut at late growth stage and SPAD value at pod setting stage, significantly improved Vc,max, Amax, and ΦPSⅠ/PSⅡ, and reduced Wk and Vj values of intercropping peanut functional leaves at pod expanding stage. The difference in these parameters between RIC and GIC were not significant. The land equivalent ratio and intercropping advantages of RIC were higher than those of FIC and GIC. Phosphorus application could further promote Vc,max, Jmax, Amax and ΦPSⅠ/PSⅡ of intercropping maize and peanut, and significantly improve yield advantages of intercropping. The findings indicated that co-ridge intercropping could enhance CO2 carboxylation and fixation by improving photosynthetic electron transport and pho-tosystems coordination, improve the photosynthetic rate of functional leaves of maize and peanut, thus increase crop yield and intercropping advantages.
为了明确玉米和花生同垄间作提高间作优势的光合机理,采用大田随机区组试验,以玉米和花生平作间作(FIC)为对照,分别在0(P0)和180 kg P2O5·hm-2(P180)两个磷水平下,分析了玉米和花生同垄间作(RIC)与玉米和花生沟垄间作(GIC)对作物叶面积指数(LAI)、SPAD值、CO2羧化能力、光系统间协调性和间作产量优势的影响。结果表明: 与FIC和GIC相比,RIC显著提高了间作玉米吐丝期SPAD值及吐丝期、乳熟期功能叶的表观量子效率(AQY)、最大电子传递速率(Jmax)、最大羧化效率(Vc,max)、CO2饱和时的净光合速率(Amax)和光系统间协调性(ΦPSⅠ/PSⅡ),降低了乳熟期功能叶K相可变荧光Fk占Fj-Fo振幅的比例(Wk)和J相可变荧光Fj占Fp-Fo振幅的比例(Vj),各指标在FIC与GIC间差异不显著。与FIC相比,RIC和GIC能够提高间作花生生育后期LAI和结荚期SPAD值,显著提高了Vc,max、Amax和ΦPSⅠ/PSⅡ,降低荚果膨大期功能叶Wk和Vj值,各指标在RIC与GIC间差异不显著。RIC的土地当量比和间作产量优势均高于FIC和GIC;施磷能进一步促进间作玉米、花生功能叶的Vc,max、Jmax、Amax和ΦPSⅠ/PSⅡ,提高间作产量优势。表明同垄间作可通过改善间作玉米、花生功能叶的光合电子传递及光系统间协调性,增强CO2羧化固定能力,提高光合速率,进而增加作物产量和间作优势。.
Keywords: CO2 carboxylation fixation; co-ridge intercropping; maize and peanut intercropping; photosystems coordination; yield advantage of intercropping.