T. Koike et al., COMPARISON OF THE PHOTOSYNTHETIC CAPACITY OF SIBERIAN AND JAPANESE BIRCH SEEDLINGS GROWN IN ELEVATED CO2 AND TEMPERATURE, Tree physiology, 16(3), 1996, pp. 381-385
The effects of increased CO2 and temperature on the photosynthetic cap
acity of Siberian white birch and Japanese white birch (Betula platyph
ylla Sukatch. and B. platyphylla Sukatch. var. japonica Hara) were mea
sured. Birch seedlings were raised with a CO2 partial pressure of 36 /- 0.3 Pa (i.e., ambient) or 70 +/- 0.6 Pa at day/night temperatures o
f either 30/16 degrees C or 26/12 degrees C. Siberian birch leaves wer
e smaller and thicker than Japanese birch leaves. Water use efficiency
and nitrogen use efficiency of Siberian birch grown in the CO2-enrich
ed air were higher than those of Japanese birch. Both species showed a
physiological adjustment to the growth CO2 partial pressure. Carboxyl
ation efficiency and quantum yield of both species grown in CO2-enrich
ed air were lower than those of seedlings grown in ambient CO2. The ad
aptation of Siberian and Japanese birch to elevated CO2 and temperatur
e are discussed in relation to predicted climate change.