2019, Vol. 17, No. 2
Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/5393
Sirvi
Sirvi 2019, Vol. 17, No. 2 Märksõna "CO2 exchange" järgi
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Kirje A research on models of the photosynthetic light response curves on the example of evergreen types of plants(2019) Korsakova, S.; Plugatar, Yu.; Ilnitsky, O.; Karpukhin, Yu.The peculiarities of CO2 exchange in the leaves of ornamental evergreen plant species that are common in the Southern coast of Crimea were studied: Nerium oleander L., Laurus nobilis L., Aucuba japonica Thunb., and Melissa officinalis L. The results of approximation of the most commonly used four models of PN/I curves with the measured data were compared. The values of the parameters 𝑃𝑔𝑚𝑎𝑥, (𝐼𝑐𝑜𝑚𝑝), 𝑅𝐷, 𝐼𝑚𝑎𝑥, which were calculated from the modified Michaelis-Menten model in comparison with the measured values were higher by 5–15%, and those that were calculated by the hyperbolic tangent model – lower by 3–13%. The use of a modified rectangular hyperbola model, which is capable of describing the photoinhibition by the nonrectangular hyperbola and the modified nonrectangular hyperbola model, showed a high degree of adequacy of the proposed models for describing the true dependence between the rate of photosynthesis and the light intensity for Nerium oleander L., Laurus nobilis L., Aucuba japonica Thunb. and Melissa officinalis L. Measurements of CO2 exchange in leaves under similar environmental conditions showed significant differences in the parameters of the PN/I curves: the light compensation point, the rate of photosynthesis and dark respiration, light saturation, and quantum yield. The highest values of photosynthesis efficiency were observed in Nerium oleander, the lowest values in Aucuba japonica – the light saturation was noted at a very low photosynthetically active radiation. The lower values of the light compensation point and the saturation constants in Laurus nobilis and Aucuba japonica indicate their effective use of the photosynthetically active radiation, which allows them to survive in conditions of durable shade.