Details

Autor(en) / Beteiligte

• Weng, J.H
• Liao, T.S
• Sun, K.H
• Chung, J.C
• Lin, C.P
• Chu, C.H

Titel

Seasonal variations in photosynthesis of Picea morrisonicola growing in the subalpine region of subtropical Taiwan

Ist Teil von

• Tree physiology, 2005-08, Vol.25 (8), p.973-979

Ort / Verlag

Canada

Erscheinungsjahr

2005

Quelle

MEDLINE

Beschreibungen/Notizen

• 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, P(nsat)), chlorophyll fluorescence (F(v)/F(m)) 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, P(nsat) remained at about 20% of the highest value observed in winter. There was a curvilinear relationship between F(v)/F(m) and the minimum or mean air temperature of the measuring day. The increase in F(v)/F(m) 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, F(v)/F(m) varied sharply. Seasonal variations in P(nsat) paralleled those in F(v)/F(m) and needle soluble protein concentration. In early or mid spring when air temperature and F(v)/F(m) increased, P(nsat) and soluble protein concentration remained low. Multiple regression analysis showed that seasonal variations in P(nsat) were affected by F(v)/F(m), air temperature and needle soluble protein concentration, and the multiple regression equation could be used to estimate P(nsat) 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.