4个薄壳山核桃品种的光合特性研究

【目的】探讨4个薄壳山核桃品种‘莫愁’‘卡多’‘绍兴’‘威奇塔’的光合与生长特性,为薄壳山核桃良种优选与推广应用提供理论依据。【方法】测定4个品种5年生嫁接苗的光合日变化、光响应曲线、叶绿素荧光以及生长量参数,并进行相关性分析。【结果】4个品种7月下旬光合日变化趋势均呈单峰型,‘绍兴’的净光合速率(P_n)峰值和日均值均高于其他3个品种,影响4个品种P_n的主要因子为光合有效辐射(PAR)、蒸腾速率(T_r)和气孔导度(G_s);‘绍兴’的最大净光合速率(P_n,max)与光饱和点(P_LSP)显著高于其他品种,光补偿点(P_LCP)和呼吸速率(R_d)低于其他品种;荧光参数光系统Ⅱ最大光化学效率(F_v/F_m)和潜在的光化学活性(F_v/F₀)均是‘绍兴’最高,‘莫愁’次之。相关性分析表明,光响应特征参数与荧光参数有极强的相关性,F_v/F_m和 F_v/F₀均与 P_n,max呈显著相关;地径与P_n,max呈极显著正相关。【结论】4个薄壳山核桃品种均具有较强的强光和高温适应能力,其中‘绍兴’的生长适应性最强,‘莫愁’次之。苗木生长与夏季光合性能之间呈明显正相关,‘绍兴’较优的光合性能主要表现为高光化学效率和较宽幅的光强利用能力。

Study on photosynthetic characteristics of four pecan cultivars

【Objective】The photosynthetic and growth characteristics of four pecan cultivars ‘Mochou’ ‘Caddo’ ‘Shaoxing’ and ‘Wichita’ were investigated to provide a scientific basis for their breeding and popularization. 【Method】Diurnal changes in photosynthesis, the light response curve, chlorophyll fluorescence and the growth parameters of five years old plants from the four grafted cultivars were investigated, and the degree of correction for these factors was analyzed.【Result】In late July, the diurnal changes in photosynthesis for the four cultivars showed single peak changes. The peak and average values for the net photosynthetic rate (P_n) of ‘Shaoxing’ were significantly higher than those of the other three cultivars. The main factors affecting P_n were found to be photosynthetically active radiation (PAR), the transpiration rate (T_r) and stomatal conductance (G_s). Analysis of the light response parameters showed that the maximum net photosynthetic rate (P_{n, max}) and the light saturation point (P_LSP) of ‘Shaoxing’ were significantly higher than for the other three cultivars, while the light compensation point (P_LCP) and the respiration rate (R_d) were lower than the other cultivars. The PSⅡ of ‘Shaoxing’ had the highest photochemical quantum yield (F_v/F_m) and potential photochemical activity (F_v/F₀), followed by ‘Mochou’. Correlation analysis showed that there was a significant correlation between the fluorescence parameters and the characteristic parameters for the light response curve. F_v/F_m and F_v/F₀ were significantly correlated with P_{n, max}, and the ground diameter was highly significantly correlated with P_{n, max}.【Conclusion】All four pecan cultivars have a strong ability to adapt to strong light and high temperatures. ‘Shaoxing’ has the strongest growth adaptability, followed by ‘Mochou’. There is an strong positive correlation between the growth and photosynthetic performance during summer. The better photosynthetic performance of ‘Shaoxing’ is mainly manifested in its high photochemical efficiency and wide light intensity use ability.