Abstract:
Meager information is available on the specific effects of root volume (V) and N concentration in the water (CN) on uptake rates of water and N by apple trees, as related to fruit yield and tree growth. To investigate this relationship, Golden Delicious/Hashabi trees were grown for 5 years in containers of 200, 50 and 101. Trees in the 200-1 containers were irrigated with a nutrient solution containing 10.7±1.3, 7.1±1.5 or 2.5±1.0 m M NO3. Trees in the remaining two container-volume treatments were uniformly supplied with a solution of 7.1±1.5 m M NO3. Elevated CN had no effect on the rate of water uptake, but increased the rate of N absorption by the trees from 2.4 to 4.8 g N tree-1 day-1 during July. The stimulated N uptake rate stemmed from enhanced fluxes of N uptake by the roots. CN had a negligible effect on root weight and root permeability to NO3 and water. The elevated N uptake rate did not result in greater fruit yield and growth, or greater N content in tree organs, indicating considerable release of N from living and decaying roots to the growth medium. Reducing the container volume decreased yield, total dry matter production and N and water uptake rates, but increased root permeability to NO3 and water, and total soluble solids in fruits. The all-season average CN in the irrigation solution above which N concentration in the transpiration stream was lower than the inflowing CN was 4.2 m M NO3. © 1988 Kluwer Academic Publishers.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם
