Taking young pear trees in Jixian Country

Shanxi Province for an example

the paper analyzes the effects of different soil water conditions on physiological characteristics of young pear tree based on a potted exper-iment. The result indicates that the daily change in t ranspirat ion rate presents a single-peak or double-peak curve and the relat ionship between water consumption of pear tree and soil water content can be described significantly by a quadratic curve. Under different soil water conditions

daily chang e in net photosynthetic rate of young pear tree presents/S0 shape

which rises to a peak at 8: 00 am and appears a midday depression of photosynthesis at 12: 00am. Soil water deficient markedly reduces photosynthetic rate. Soil water content suitable for high w ater use ef f-iciency is 10% ~ 14%. The dried weig ht of leaves and total biomass of young pear tree has a downtrend w ith decreased soil water content. U nder the normal soil water condition

the proportions of biomass overground and underground are nearly the same

but the greater photosynthetic production of young pear tree tends to occur in the underground.