Sayan Sdoodee and Junjira Somjun

pp. 561 - 564

Abstract

Measurements of stem water potential, leaf water potential and stomatal conductance were simultaneously done in 3-year old trees of neck orange. The trees were subjected to 3 levels of watering: 1) daily watering (control), 2) 4-day interval watering and 3) 8-day interval watering. It was found that stem water potential was more sensitive to soil moisture than leaf water potential. This led to high correlation between soil moisture and stem water potential (r² = 0.80), but the correlation between soil moisture and leaf water potential was low (r² = 0.66). Likewise, stomatal conductance was highly
correlated with stem water potential (r²= 0.74). The correlation was higher than that of stomatal conductance with leaf water potential (r² = 0.62). Therefore, stem water potential appears to be a sensitive indicator to assess water stress in neck orange.