Weng Jen-Hsien, Liao Tien-Szu, Sun Kuo-Hu, Chung Ji-Chy, Lin Chung-Ping, Chu Chung-Hei
Department of Life Science, National Chung-Hsing University, Taichung, Taiwan.
Tree Physiol. 2005 Aug;25(8):973-9. doi: 10.1093/treephys/25.8.973.
From January 1999 to May 2001, we investigated seasonal variations in the photosynthetic capacity of Taiwan spruce (Picea morrisonicola Hay.) growing in the subalpine region of subtropical Taiwan (23 degrees 29' N, 120 degrees 53' E, 2600 m a.s.l.). Photosynthetic capacity (near light-saturated net photosynthetic rate, Pnsat, chlorophyll fluorescence (Fv/Fm) and soluble protein concentration of needles all increased from mid or late spring to early winter. Even when minimum air temperature of the measuring day dropped to near 0 degrees C, Pnsat remained at about 20% of the highest value observed in winter. There was a curvilinear relationship between Fv/Fm and the minimum or mean air temperature of the measuring day. The increase in Fv/Fm with temperature was slowed when the daily mean air temperature was above 7 degrees C, or the minimum air temperature was above 3 degrees C; however, when air temperatures dropped below these values, Fv/Fm varied sharply. Seasonal variations in Pnsat paralleled those in Fv/Fm and needle soluble protein concentration. In early or mid spring when air temperature and Fv/Fm increased, Pnsat and soluble protein concentration remained low. Multiple regression analysis showed that seasonal variations in Pnsat were affected by Fv/Fm, air temperature and needle soluble protein concentration, and the multiple regression equation could be used to estimate Pnsat in different seasons. We conclude that the decrease in photosynthetic capacity of Taiwan spruce in winter and its subsequent recovery in spring were mainly caused by photoinhibition and its reversal, and changes in needle soluble protein concentration. Another possible explanation for the delayed recovery of photosynthetic capacity in spring may be associated with the slow increase in needle soluble protein concentration.
1999年1月至2001年5月，我们对生长在亚热带台湾亚高山地区（北纬23度29分，东经120度53分，海拔2600米）的台湾云杉（Picea morrisonicola Hay.）的光合能力季节性变化进行了调查。光合能力（接近光饱和净光合速率Pnsat、叶绿素荧光（Fv/Fm）和针叶可溶性蛋白浓度）从春末或夏末到初冬均有所增加。即使测量日的最低气温降至接近0摄氏度，Pnsat仍保持在冬季观测到的最高值的约20%。Fv/Fm与测量日的最低或平均气温之间存在曲线关系。当日平均气温高于7摄氏度或最低气温高于3摄氏度时，Fv/Fm随温度升高的速度减缓；然而，当气温降至这些值以下时，Fv/Fm变化剧烈。Pnsat的季节性变化与Fv/Fm和针叶可溶性蛋白浓度的变化平行。在早春或仲春，当气温和Fv/Fm升高时，Pnsat和可溶性蛋白浓度仍然较低。多元回归分析表明，Pnsat的季节性变化受Fv/Fm、气温和针叶可溶性蛋白浓度的影响，该多元回归方程可用于估算不同季节的Pnsat。我们得出结论，台湾云杉冬季光合能力的下降及其随后在春季的恢复主要是由光抑制及其逆转以及针叶可溶性蛋白浓度的变化引起的。春季光合能力恢复延迟的另一个可能解释可能与针叶可溶性蛋白浓度的缓慢增加有关。
