Rakhmankulova Z.F., Shuyskaya E.V., Khalilova L.A., Orlova Y.V., Burundukova O.L., Velivetskaya T.A., Ignat'ev A.V.
В журнале Russian Journal of Plant Physiology
Год: 2020 Том: 67 Номер: 5 Страницы: 490-500
The plants from two populations (P1 and P2) of xero-halophyte Sedobassia sedoides (Pall.) Freitag & G. Kadereit (Chenopodiaceae) with С3–С4 intermediate type of photosynthesis were examined. Morphophysiological parameters were determined: dry biomass of the above-ground organs, maximum quantum yield of photosystem II (PSII), ultra- and mesostructure of the leaf, carbon isotope discrimination (δ13С) in plants grown under normal conditions and exposed to moderate salinization (0 and 200 mM NaCl). By the values of δ13С and efficiency of PSII, we did not detect significant differences between the populations. Under control conditions, the chloroplasts and mitochondria were located in Kranz-like cells of the bundle sheath of both populations in the region adjacent to vascular bundle, which is characteristic of С2 type of photosynthesis (with photorespiratory СО2 concentrating mechanism). P2 plants were notable for a greater volume of Kranz-like cells of the bundle sheath and more numerous, larger chloroplasts and mitochondria than in P1 plants. By structural leaf parameters, P1 plants may be attributed to a proto-Kranz type of photosynthesis (intermediate between С3 and С2 types) and P2 plants to С2 photosynthesis. Under salinization, the accumulation of dry biomass was reduced in both populations but more considerably in P1. The ultrastructure of organelles in both populations showed different responses to salinization, which was especially pronounced in Kranz-like cells of the bundle sheath. In P1 plants, the area of chloroplasts and mitochondria rose, whereas the area and number of chloroplasts under stress did not change in P2 plants but the area and number of mitochondria decreased. In the cells of plants from both populations, signs of degradation were observed (more pronounced in P1 plants); they were shown in chloroplasts twisting and a disturbance of their granal stacking. In P2 plants, Kranz-like cells of the bundle sheath preserved safer organelles but there occurred the cells with complete degradation of a vacuolar type. Thus, intraspecific ultra- and mesostructural differences were detected in plants from two populations of С3–С4 intermediate species S. sedoides, which reflect different stages of development of photorespiratory СО2 concentrating mechanism. Under salinization, the plants from two different populations showed unlike strategies of adaptation on the level of leaf ultra- and mesostructure.
