engleski

The photosynthetic responses of two Brassica species to the short-term salinity stress

In order to investigate early photosynthetic responses of Chinese cabbage (B. rapa ssp. pekinensis) and kale (B. oleracea var. acephala) to the increased salinity, photosynthetic performance, chlorophylls concentration and relative accumulation levels of the photosynthetic proteins (Rubisco LSU, Cyt f, LHC b II and D1) were analyzed. Plants were grown hydroponically, treated with NaCl in a range of conc. 0-200 mM for a short-term (24 hours). Results showed that investigated species had different tolerance to the salt stress what was based on their different photosynthetic adjustment strategies. Kale, as a more salt tolerant species, revealed considerably better photosynthetic performance under increased salinity conditions due to more competent electron transport, in comparison to the moderately sensitive Chinese cabbage. On the other hand, Chinese cabbage plants decreased considerably their photosynthetic performance under the salt stress conditions. This was due to the less competent electron transport as well as increased light harvesting and trapping properties of PSII. This led to the increase in dissipation flux and the modification of a certain number of RC from active to dissipative ones. The observed differences in the photosynthetic performance of two investigated species corresponded to the differential accumulation of chlorophylls and photosynthetic proteins that regulate electron transport and light harvesting.

Chinese cabbage, kale, chlorophyll a fluorescence kinetics, PSII, short-term salinity stress

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