| Liliaceae Polygonatum odoratum(Mill.) Druce, a perennial plant, is a kind of wild herb with great potentials. By now physiological and ecological properties of photosynthesis for Polygonatum rdoratum hasn't been yet systematically studied home and abroad. In this article, two-year old Polygonatum odoratum growing in the wild conditions was used as materials to systematically study its physiological and ecological properties of photosynthesis. Also experiment of studying photosynthetic properties under artificial conditions was designed to understand the effect causing by interaction between the plant internal physiological factors and environmental factors. Besides, studying on the relevant relation between non-uniform stomatal closure and modified Ci value was conducted with the purpose to establish a mathematical model between them and try to reveal the relevant relationstruly and precisely.The following results of the properties of photosynthetic ecology and physiology in wild Polygonatum odoratum leaves had been obtained by several years' work:1. For clear days, daily course of net photosynthetic rate (Pn) existed in polygonatum odoratum was the single-peaked pattern. In general, Pn level reached its peak at noon then decreased. It was found that the ambient conditions and internal physiological status of the plant would codetermine the actual level of Pn at every moment. On clear days, the Pn of polygonatum odoratum ascended by the increasing photon flux density (PFD) and ambient temperature (AT). Under shading treatment(50%), The Pn ,light saturation point and light compensation point decreased slightly. When PFD was artificially increased by 150%, the daily course of Pn was two-peaked pattern.Under high CO2 (700 mol mol-1), the Pn increased while decreased under low CO2(40 mol mol-1) AC350 Which is the net photosynthetic rate at Ci=350 mol mol-1 always decreased during the period form morning to afternoon on clear days.Generally, when the Pn of polygonatum odoratum reached the peak, relative humidity (RH) was the lowest on a clear day, so the daily course of Pn roughly mirrored the daily trend of RH. Pn was also influenced by the accumulation of photosynthetic product in polygonatum odortum2. On clear days, changes in apparent quantum yield ( 1) which represent the efficiency of polygonatum odoratum leaves in utilizing light energy followed a daily pattern of decreasing from morning to noon then increasing, reaching the lowest around noon. 1 decreased or increased by the ascending or decline of PFD and temperature. Shading treatment (50%) led to the increasing of 1. The 1 of polygonatum odoratum at every moment in a day was almost similar under the constanttemperature. Low O2 treatment(2%), under which plant photorespiration didn't existed, compared with the obvious decline of the control, the 1 of polygonatum odoratum from morning to noon didn'tremarkable decreased.3. Under artificially control conditions (PFD: 700 mol m-2; AT.- 25?癈; RH: 70% 10%), daily changes of Rs in polygonatum odoratum leaves still existed with slight increasing from morning to noon then decreasing. Carboxyiation efficiency (CE) of polygonatum odoratum didn't declined until 8-hour irradiation, while AC350 still decreased from morning to noon.4. Seasonal changes of diurnal maximum Pn m polydonatum odoratum leaves followed a regular course with higher value during the period from June to August while relatively lower during the period from April to May, September to November. Similar to the seasonal changes of Pn, the corresponding annual changes of transpiration rate (E) of polydonatum odoratum, PFD, AT, and RH also were single-peaked patterns.The results obtained from path coefficient analysis showed that among three ecological factors affecting Pn of polynatum odoratum, PFD was the dominant factor. However, among three physiological factors affecting Pn, the dominant factor was Rs.5. In this part, the diurnal change of stomatal opening and closure of polydonatum odoratu...
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