Water relations of needle of tall Cryptomeria japonica tree

Abstract

Tree's water condition depends on soil moisture, air humidity, and height growth.
Photosynthetic rate and water relations' parameters of Cryptomeria japonica needle cells living in various water conditions were determined, such as soil dryness/wetness, air humidification, and tall/short tree crown.
The results indicate that needles can adapt to bad water conditions, and also to temporary water deficit by diurnal osmotic adjustment and/or diurnal change of cell wall elasticity. Those diurnal adaptations seem to be more remarkable in the needles living in good water condition. This is important for trees to live and grow under water stress.