| The mechanical models of the photosynthesis were established from the leaves to the canopies of nigra L. and hindsi L.'s seedlings of 1 or 2 years old, using solar radiation as dominant environmental factor and the response of photosynthesis to environment as main clue; on this account, the accumulation and distribution dynamic models of black walnut's dry matter were set up. The quantitative relation between black walnut's ecophysiological processes from organ, individual to population and environmental factors was systematically studied. The purpose of this research is to provide theoretical support for the regionalization, standardization and refinement of fruit tree cultivation, and to provide basic theories for the study on ecological adaptation of black walnu and its development in China. The main results of the research are as follows.l.A coupled model of photosynthesis - stomatal conductance was set up by means of uniting biochemical model of photosynthesis introduced by Farquhar with B-B model of stomatal conductance. And the estimated results by this coupling model correspond with the measured materials. The model to simulate CO2 concentration in leaf substomatal cavity (Ci)-one submodel in the coupling model, was put forward by way of gas transmission theory.2. Under the condition of water and fertilizer optimum in the field, and when PAR maintains 1000 u mol. m'V and CO2 concentration in the air doubles (from 350 to 700 V- mol. mol"1), the leaf photosynthetic rate of nigra and hindssi respectivelyincreases by 25.3% and 26.2%.The response of the photosynthetic rate to temperature is a one - humped curve, and their optimal temperature is respectively about 25.3 and 26.8,when CO2 concentration in the air is at 350 n mol 'mol'1 and PAR at 1000 u mol m'V. When the temperature is below the optical, the response of their photosynthetic rate to temperature is little different; but when the temperature is over the optimal, hindssi's photosynthetic rate is obviously higher than nigra's, which means the former is more adaptable to environment.The response of their photosynthetic rate to PAR is consistent with Michaelis-Menten's when CO2 concentration and temperature in the air keep constant (350 u mol ?mol'1 and 25.0). In typical clear days, the daily course of their photosynthetic rate presents a double-humped curve, which has two maximums at about 10:00 and 16:00; about at noon, their photosynthetic rate is relatively lower.3. On the basis of Ross's and Nilson's models of leaf declination distribution and mathematization of geometric structure of canopies, the highly distinguishable models of canopy structures and the transmissive submodels of direct and diffused radiation in the canopies were set up according to their qualities and transmissive characteristics. The leaf photosynthetic rates of "facula region" and ''umbrageous region" in the canopies were calculated to make the multiplayered model more exact.The extinction coefficients in the canopies of nigra of 1 year old and hindiss of 2 years old are obviously daily changeable, especially before 8:00 or after 16:00. In typical clear days, the canopy photosynthetic rate of hindssi (LAI=6 about) reaches the maximum, the rate being the same probably at the corresponding moment in morning and in afternoon; however, that of nigra (LAI=3 about) reaches the maximum at 11:00, the rate being different at the corresponding moment in morning and in afternoon.4. Under the condition of water and fertilizer optimum, the accumulative and distribution models of photosynthetic dry matter were set up according to matter conservation laws and concentration gradient theories. Supposing the concentration of assimilation product in every organ is in direct proportion with its photosynthate gained. The formula of dry matter transmissive flux (K,) is as follows.And the estimated values with the models fitted the measured material in the field .During the period of the canopy forming of nigra of 1 year old, the dry matter accumulation of the...
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