Preliminary Research In Carbon Sequestration And Oxygen Release And Photosynthetic Characteristics Of Datura Stramonium

Datura stramonium for annuals erect large herbaceous plants, adaptive to the marginal land habitat, are potential energy plant. During June to September, daily changes of physiological characteristics indexes (including net photosynthetic rate, photosynthetically active radiation intensity and stomatal conductance) and monthly average changes of net photosynthetic rate and chlorophyll content of potential energy plant Datura stramonium L. were measured with LI-6400 portable photosynthesis system, light and CO₂ response curves of net photosynthetic rate were fitted with non-rectangular hyperbola; The same time, net photosynthetic rate and chlorophyll content of Datura stramonium L. were studied in different plant density, soil moisture, nitrogen concentration,NaCl concentration, and preliminary discussion in Carbon Sequestration and Oxygen Release of Datura. The results show that, (1) during experimental period (June to September), daily changes of photosynthetically active radiation intensity and net photosynthetic rate of D. stramonium leaves are'single peak type'with a peak occurring at about 11:00, and peak value of net photosynthetic rate in July is the highest with a value of (19.01±0.82)μmol·m^-2·s^-1. Daily change of stomatal conductance is'double peak type', the highest peak and secondary peak values appear at 12:00 and 14:00, respectively. Monthly averages of net photosynthetic rate in different months have extremely significant differences (P<0.01), in which that in July is the highest with a value of (9.41±0.04)μmol·m^-2·s^-1. Changes of monthly averages of chlorophyll content is similar to that of net photosynthetic rate in different months, and monthly average of chlorophyll content in July is also the highest, but monthly averages of Chla, Chlb and total chlorophyll contents have a certain difference. (2) Light and CO₂ response curves of net photosynthetic rate of D. stramonium are similar, both of them increase linearly under low photosynthetically active radiation intensity and CO₂ concentration conditions, then increase slowly after reaching of a saturation point, and tend to steady at last. Light compensation point and light saturation point of D. stramonium are 22.42 and 689.26μmol·m^-2·s^-1, respectively, while CO₂ compensation point and CO₂ saturation point are 74.06 and 1331.97μmol·mol^-1, respectively. It is concluded that D. stramonium is a shade-tolerant capability with a certain positive for C3 plants. (3) D. stramonium leaf net photosynthetic rate of different plant density, soil moisture, nitrogen concentration, NaCl concentration was no significant difference in the response, while the chlorophyll content of the response to these factors a significant difference(P<0.05), this shows that three factors on the D. stramonium through the influence of chorophyll content role.(4) The maximum leaf area net carbon storage of D. stramonium was (6.01±0.019) g·m^-2·d^-1, the largest unit of leaf area on plants release oxygen was (5.46±0.017) g·m^-2·d^-1, the carbon sequestration capacity is equal with Hippophae rhamnoides Linn. Which is important energy plants.