连续施用生物炭对花生不同生育时期叶绿素荧光特性的影响

【目的】通过测定花生不同生育时期功能叶片的叶绿素荧光特性,探讨连续9年施用不同用量生物炭对花生叶片光系统Ⅱ的电子传递、光能吸收和氧化还原性能影响规律,同时观测叶片放氧复合体（OEC）受损程度变化趋势,为指导花生施肥提供理论支撑。【方法】于2011年建立的田间定位试验,设3个处理：CK（不施肥）;C15（生物炭225 kg·hm^-2）;C50（生物炭750 kg·hm^-2）。2019年分别采集不同生育时期花生功能叶,利用M-PEA-2仪器测定暗处理后的叶片光合指标。 【结果】通过分析不同生育时期花生功能叶叶绿素荧光参数发现,连续施用不同用量生物炭对快速叶绿素荧光动力学曲线（OJIP曲线）有显著影响。C15处理的K点的相对可变荧光强度差（ΔV_T）在花生苗期和开花下针期分别为-0.002和-0.020,在结荚期和成熟期分别为-0.024和-0.053,与CK处理相比花生各生育时期功能叶K点的相对可变荧光强度显著降低;随着生物炭用量的增加,开花下针期与成熟期K点降低幅度有不同程度增大。花生功能叶叶绿素荧光参数在开花下针期和成熟期对生物炭的连续施用有积极响应,其具体表现为：在开花下针期,与CK处理相比C15处理的J点相对可变荧光强度（V_J）降低23.9%,初级醌受体（Q_A）被还原速率（M_O）降低32.1%,捕获的激电子将电子传递到电子传递链中Q_A下游的其他电子受体的速率（Ψ_O）增加25.0%,以吸收光能为基础的光化学性能指数（PI_ABS）增加154.6%。缓解了花生功能叶片的放氧复合体（OEC）受损程度,提高电子由初级醌受体（Q_A）向电子传递链下游的其他电子受体传递的能力,随着生物炭用量的增加,效果越明显。在成熟期,施用不同量生物炭对花生叶片叶绿素荧光特性指标的影响与开花下针期基本一致,具体表现为：C15处理较CK处理J点相对可变荧光强度（V_J）和初级醌受体（Q_A）被还原速率（M_O）显著降低,分别减少12.5%和16.0%,捕获的激电子将电子传递到电子传递链中Q_A下游的其他电子受体的速率（Ψ_O）增加7.8%,以吸收光能为基础的光化学性能指数（PI_ABS）增加73.7%;C50处理与CK处理相比J点相对可变荧光强度（V_J）减少13.2%,初级醌受体（Q_A）被还原速率（M_O）减少19.4%,捕获的激电子将电子传递到电子传递链中Q_A游的其他电子受体的速率（Ψ_O）增加8.2%,以吸收光能为基础的光化学性能指数（PI_ABS）增加79.7%。【结论】连续施用生物炭能显著提高花生功能叶片在开花下针期和成熟期光系统Ⅱ电子传递效率,缓解OEC损伤程度,从而提高花生功能叶的光合性能。

Effects of Continuous Application of Biochar on Chlorophyll Fluorescence Characteristics of Peanut at Different Growth Stages

【Objective】By measuring the photosynthetic performance indexes of functional leaves of peanut at different growth stages, the effects of different amounts of biochar on electron transport, light energy absorption and redox properties of peanut leaves photosome II were studied for 9 years in a row. Meanwhile, the change trend of leaf oxygen evolution complex (OEC) damage degree was observed to provide the theoretical support for guiding peanut fertilization. 【Method】 A field experiment was conducted in 2011 with three treatments: CK (no fertilization), C15 (biochar 225 kg·hm^-2), and C50 ( biochar 750 kg·hm^-2). In 2019, the peanut functional leaves at different growth stages were collected, and the photosynthetic indexes of leaves after dark treatment were measured by M-PEA-2 instrument.【Result】By analyzing the chlorophyll fluorescence parameters of peanut functional leaves at different growth stages, it was found that continuous application of biochar had a significant effect on the rapid chlorophyll fluorescence kinetic curve (OJIP curve). The relative variable fluorescence intensity difference (ΔV_t) of K point treated with C15 was -0.002 and -0.020 at seedling stage and flowering and needle setting stage, and -0.024 and -0.053 at pod setting stage and maturity stage. Compared with CK treatment, the relative variable fluorescence intensity of K point in functional leaves of peanut at different growth stages was significantly decreased; with the increase of biochar dosage, the decrease range of K point at flowering, needling and mature stages increased in varying degrees. The chlorophyll fluorescence parameters of peanut functional leaves had a positive response to the continuous application of biochar at the flowering, needling and maturity stages. Compared with CK treatment, the relative variable fluorescence intensity at the J-step (V_J) under C15 treatment decreased by 23.9%, the approximated initial slope of the fluorescence transient (M_O) decreased by 32.1%, and the rate at which trapped excitons transfer electrons to other electron receptors downstream of Q_A in the electron transport chain (Ψ_O) increased by 25.0%.The performance index on absorption basis (PI_ABS ) increased by 154.6%, which alleviated the damage of oxygen releasing complex (OEC) in peanut functional leaves and improved the ability of electron transfer from primary quinone receptor (Q_A) to other electron receptors downstream of electron transport chain, and its effect on chlorophyll fluorescence performance increased. With the increase of biochar dosage, the effect was more obvious. At the mature stage, the effects of biochar application on chlorophyll fluorescence characteristics of peanut leaves were basically consistent with those at flowering and needling stage. The specific performance was as follows: the relative variable fluorescence intensity at the J-step (V_J) and the approximated initial slope of the fluorescence transient (M_O) under C15 treatment were significantly lower than those under CK treatment 12.5% and 16.0%, respectively, and the trapped excitons transferred electrons into the electron transfer chain (Q_A).Compared with CK treatment, the relative variable fluorescence intensity at the J-step (V_J) decreased by 13.2%, and the approximated initial slope of the fluorescence transient (M_O) decreased by 19.4%. The probability that a trapped exciton moved an electron into the electron transport chain beyond Q_{A (}Ψ_O) was 8.2%, and the performance index on absorption basis (PI_ABS) increased by 79.7%.【Conclusion】Continuous application of biochar could increase the electron transfer efficiency of photosystem II in functional leaves of peanut at the time of flowering and maturity, and improve the photosynthetic performance of functional leaves of peanut during this period.