RELATIONSHIP BETWEEN PHYSIOLOGICAL INDICATORS OF OAT AND METEOROLOGICAL FACTORS IN TIBET'S ALPINE PASTORAL AREAS.

According to large daily temperature difference, strong solar radiation and significant change of air humidity in the alpine area of Tibet, a field experiment was conducted to analyze the oat's diurnal variation of the leaf water potential (ψ_L), transpiration rate (Tr) and net photosynthetic rate (Pn). Meanwhile, the relationship between oat's physiological indicators and typical meteorological factors (atmospheric temperature (T), solar radiation (R_s), relative air humidity (RH)) were investigated with regression models. Results showed that the oat's daily change curve of ψ_L showed 'V-type' in the seeding and heading stages and 'W-type' in the jointing and tillering stages. As shown in the results, oat's Pn presented a decreasing tendency in a day and the peak appearing between 9:00 and 10:00 at one day in each growing stage. The Tr presented double-peak curves and midday depression in the seeding and heading stages. The variation tendency about oat's Tr in the tillering stage and jointing stage was "Multipeak" type without distinct midday depression and parabolic tendency. By multiple regression analysis between the data of oat's physiological indexes and comprehensive factors, the ψ_L, Tr and Pn of oat in alpine region can be predicted under condition of adequate water supply. [ABSTRACT FROM AUTHOR]