Net photosynthetic rates(Pn) were measured in 18-month-old seedlings of Machilus pauhoi from two provenances of Suichuan in Jiangxi and Jian’ou in Fujian using a LiCor LI-6400 portable photosynthesis system(LiCor Inc...Net photosynthetic rates(Pn) were measured in 18-month-old seedlings of Machilus pauhoi from two provenances of Suichuan in Jiangxi and Jian’ou in Fujian using a LiCor LI-6400 portable photosynthesis system(LiCor Inc.,Lincoln,NE,USA) with a LED light source. The other photosynthetic parameters,including maximum net photosynthetic rate(Pmax),apparent quantum yield(AQY),light saturation point(LSP) and light compensation point(LCP),were also detected in response to irradiation. The results showed: The average P max,AQY,LSP and LCP of the seedlings from the two provinces were 12.65 μmolCO2.m -2 s -1,0.052 7 μmolCO2.μmol -1 photons,1 120.99 μmol.m -2 s -1 and 18.03 μmol.m -2 s -1 respectively. There were significant differences between the two provenances in the all photosynthetic parameters except for AQY. The provenance of Suichuan performed better than that from Jian’ou with higher P max,AQY and LSP of 30.48%,4.66% and 25.70% respectively,though the LCP of Suichuan provenance was higher and needed stronger illumination. There was more variation in P max,AQY,LSP and LCP between the two provenances than that within the two provenances. There were significant differences between the upper and lower crown layers with higher P max and AQY in the upper crown,while there was no difference in LCP and LSP between the two crown layers due to the integrated influence of the shape of seedling crowns and the photosensitivity of leaves.展开更多
研究了腾格里沙漠东南缘沙坡头地区不同建植年限（16、21、27、44和52a）人工植被区中发育藻结皮的净光合速率、年固碳量和累计固碳量变化特征,并分析了其与结皮生物学参数（盖度和生物量）和土壤表层0-3 cm有机碳含量的相关关系。结果...研究了腾格里沙漠东南缘沙坡头地区不同建植年限（16、21、27、44和52a）人工植被区中发育藻结皮的净光合速率、年固碳量和累计固碳量变化特征,并分析了其与结皮生物学参数（盖度和生物量）和土壤表层0-3 cm有机碳含量的相关关系。结果表明：1）随着人工植被区建植年限的增加,藻结皮的最大净光合速率显著增加,从植被建植16a藻结皮的1.63μmol m^-2s^-1增加至植被建植52a的2.81μmol m^-2s^-1;藻结皮的最大光合速率与结皮生物量和结皮盖度呈显著正相关关系;2）藻结皮的年固碳量随植被区建植年限的延长呈指数增加,随着人工植被区建植年限的增加,藻结皮的年固碳量显著增加,从建植16a藻结皮的C 0.2 g m^-2a^-1增加到52a的C 2.78 g m^-2a^-1;3）植被区建植后,藻结皮的固碳总量经历两个阶段的变化,建植16a到27a,藻结皮固碳总量在C 2.2-6.2 g m^-2,建植44a后,固碳总量增加到C 23.9 g m^-2;并且,藻结皮的固碳总量与土壤表层有机碳含量呈显著线性正相关关系。以上研究结果说明,随着人工植被固沙区的演替,藻结皮发育成熟度逐渐提高,其光合固碳能力显著提高,有利于干旱区土壤有机碳的累计。展开更多
文摘Net photosynthetic rates(Pn) were measured in 18-month-old seedlings of Machilus pauhoi from two provenances of Suichuan in Jiangxi and Jian’ou in Fujian using a LiCor LI-6400 portable photosynthesis system(LiCor Inc.,Lincoln,NE,USA) with a LED light source. The other photosynthetic parameters,including maximum net photosynthetic rate(Pmax),apparent quantum yield(AQY),light saturation point(LSP) and light compensation point(LCP),were also detected in response to irradiation. The results showed: The average P max,AQY,LSP and LCP of the seedlings from the two provinces were 12.65 μmolCO2.m -2 s -1,0.052 7 μmolCO2.μmol -1 photons,1 120.99 μmol.m -2 s -1 and 18.03 μmol.m -2 s -1 respectively. There were significant differences between the two provenances in the all photosynthetic parameters except for AQY. The provenance of Suichuan performed better than that from Jian’ou with higher P max,AQY and LSP of 30.48%,4.66% and 25.70% respectively,though the LCP of Suichuan provenance was higher and needed stronger illumination. There was more variation in P max,AQY,LSP and LCP between the two provenances than that within the two provenances. There were significant differences between the upper and lower crown layers with higher P max and AQY in the upper crown,while there was no difference in LCP and LSP between the two crown layers due to the integrated influence of the shape of seedling crowns and the photosensitivity of leaves.
文摘用美国Li-Cor公司生产的Li-6400光合作用测定仪控制CO2浓度和温度,测量了华北平原冬小麦(Triticum aestivum)的光响应数据。分别用C3植物光响应新模型、直角双曲线模型、非直角双曲线模型和Prado-Moraes模型拟合这些实测数据,分析了由直角双曲线模型、非直角双曲线模型和Prado-Moraes模型拟合这些数据得到的最大净光合速率(The maximum net photosynthetic rate)远大于实测值,而光饱和点(Light saturation point)远小于实测值的原因。结果表明,由C3植物光响应新模型拟合的结果与实测数据符合程度最高(R2=0.9994和R2=0.9987);表观量子效率(Apparent quantum yield)不是一个理想的表示植物利用光能的指标,建议用植物光响应曲线在光补偿点处的量子效率作为表示植物光能利用的指标。
文摘研究了腾格里沙漠东南缘沙坡头地区不同建植年限（16、21、27、44和52a）人工植被区中发育藻结皮的净光合速率、年固碳量和累计固碳量变化特征,并分析了其与结皮生物学参数（盖度和生物量）和土壤表层0-3 cm有机碳含量的相关关系。结果表明：1）随着人工植被区建植年限的增加,藻结皮的最大净光合速率显著增加,从植被建植16a藻结皮的1.63μmol m^-2s^-1增加至植被建植52a的2.81μmol m^-2s^-1;藻结皮的最大光合速率与结皮生物量和结皮盖度呈显著正相关关系;2）藻结皮的年固碳量随植被区建植年限的延长呈指数增加,随着人工植被区建植年限的增加,藻结皮的年固碳量显著增加,从建植16a藻结皮的C 0.2 g m^-2a^-1增加到52a的C 2.78 g m^-2a^-1;3）植被区建植后,藻结皮的固碳总量经历两个阶段的变化,建植16a到27a,藻结皮固碳总量在C 2.2-6.2 g m^-2,建植44a后,固碳总量增加到C 23.9 g m^-2;并且,藻结皮的固碳总量与土壤表层有机碳含量呈显著线性正相关关系。以上研究结果说明,随着人工植被固沙区的演替,藻结皮发育成熟度逐渐提高,其光合固碳能力显著提高,有利于干旱区土壤有机碳的累计。
