Photosynthetic potentials of in vitro-grown juvenile, adult, and rejuvenated Sequoia sempervirens (D. Don) Endl. shoots

In vitro shoot tips of Sequoia sempervirens (D. Don.) Endl.—including a juvenile, two adult, and two rejuvenated adult clones—were examined for differences in basic physiological characteristics. Moisture contents were the same, around 85%, for all tissues regardless of origin. Growth rates, determined by fresh weight increase and shoot elongation, were higher for the juvenile and rejuvenated shoots. They correlated with higher total nitrogen contents. Juvenile and rejuvenated shoots also showed higher rates of photosynthesis and respiration, evidenced by faster O2 evolution and consumption. The photosynthetic rates were associated with more chlorophyll, especially chlorophyll a, in the juvenile and the rejuvenated shoots. Nevertheless, identical quantum efficiencies of photosystem II indicated the same photosystems were operating and with equal effectiveness in juvenile, adult, and rejuvenated tissues.