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【目的】探究稀土铈对太子参生长和光合特性的影响,以期提高太子参产量,并通过探讨铈对太子参的增产效应及其机制,为太子参高效栽培提供理论和应用依据。【方法】通过不同质量浓度稀土铈(CK、25、100、400和700 mg/L)处理后,对太子参生长指标和光合特性进行测定,并进行数据分析。【结果】随着铈质量浓度的增加,太子参植株苗高和地径相对生长量、块根长、块根直径、块根鲜质量及干质量、单位面积产量,以及叶片叶绿素和类胡萝卜素总量均表现先增加后下降的趋势,呈明显的浓度效应,以400 mg/L处理效果最佳,其中单位面积块根鲜、干质量产量分别比对照提高42.59%和41.83%。适当质量浓度稀土铈处理能显著提高光合日变化参数净光合速率(P_n)、气孔导度(Gs)、蒸腾速率(Tr)日均值,而使胞间二氧化碳浓度(C_i)降低,有效缓解光合“午休”现象。试验期间,PSⅡ最大光化学效率(F_v/F_m)、PSⅡ有效光化学效率(F_v’/F_m’)、PSⅡ实际光化学效率(Φ_(PSⅡ))和光化学淬灭系数(C_(PQC))随着稀土铈质量浓度的增加均呈现先升后降的趋势,非光化学淬灭系数(CNPQ)则呈相反的趋势。相关分析表明稀土处理下苗高、地径与P_n呈极显著正相关,P_n与叶绿素含量、类胡萝卜素含量、Gs、Φ_(PSⅡ)和F_v’/F_m’呈显著正相关,而与C_i、C_(NPQ)成负相关。灰色关联分析表明,色素含量、Φ_(PSⅡ)和F_v’/F_m’和C_(PQC)是制约太子参光合作用的主要因素。【结论】适当质量浓度的稀土铈处理能有效促进太子参生长、提高块根产量,改善光合性能。其对太子参光合作用的调节作用与促进光能吸收、转换、提高光化学效率、缓解光抑制有关。与气孔因素相比,非气孔限制因子的改善是其缓解光合“午休”现象的主要原因。
【Objective】 The purpose of this study was to investigate the effects of rare earth cerium on the growth and photosynthetic characteristics of Pseudostellaria heterophylla, in order to improve the yield of Pseudostellaria heterophylla and to provide theory and application basis for the efficient cultivation of Pseudostellaria heterophylla by exploring the stimulation effect and mechanism of cerium on Pseudostellaria heterophylla. 【Method】 The growth parameters and photosynthetic characteristics of Pseudostellaria heterophylla were determined by different concentrations of rare earth cerium (CK, 25, 100, 400 and 700 mg / L), and the data were analyzed. 【Result】 With the increase of the mass concentration of cerium, the seedling height and relative growth of root diameter, length of root, diameter of root, fresh and dry mass of root tuber, yield per unit area, and the total amount of chlorophyll and carotenoid The trend of first increase and then decrease was obvious concentration effect, and the treatment effect of 400 mg / L was the best. The fresh and dry mass yield per unit area increased by 42.59% and 41.83% respectively compared with the control. Rare earth cerium treatment could significantly increase photosynthetic diurnal variation of net photosynthetic rate (P_n), stomatal conductance (Gs), transpiration rate (Tr) daily average, while the intercellular carbon dioxide concentration (C_i) decreased, effectively alleviate photosynthesis “Lunch break” phenomenon. During the experiment, the maximum photochemical efficiency of PSⅡ (F_v / F_m), the effective photochemical efficiency of PSⅡ (F_v ’/ F_m’), the actual photochemical efficiency of PSⅡ (Φ_ (PSⅡ) and the photochemical quenching coefficient (C_ (PQC) The increase of mass concentration showed a trend of first increasing and then decreasing. The non-photochemical quenching coefficient (CNPQ) showed the opposite trend. Correlation analysis showed that seedling height and diameter had a significant positive correlation with P_n under rare earth treatment. P_n had significant positive correlation with chlorophyll content, carotenoid content, Gs, Φ_ (PSⅡ) and F_v ’/ F_m’ C_ (NPQ) is negatively correlated. Gray correlation analysis showed that pigment content, ΦⅡ (PSⅡ) and F_v ’/ F_m’, and C_ (PQC) were the main factors that restricted the photosynthesis of P. heterophylla. 【Conclusion】 Rare-earth cerium treatment with appropriate mass concentration can effectively promote growth of Pseudostellaria heterophylla, increase root yield and improve photosynthesis. The regulation effect on the photosynthesis of Radix Pseudostellariae is related to the promotion of light energy absorption, conversion, improvement of photochemical efficiency and alleviation of light inhibition. Compared with the stomatal factors, the improvement of non-stomatal limitation factors is the main reason for alleviating photosynthesis and lunch break.