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Associated growth of C₃ and C ₄ desert plants helps the C ₃ species at the cost of the C ₄ species

Su, Peixi, Yan, Qiaodi, Xie, Tingting, Zhou, Zijuan, Gao, Song
Acta physiologiae plantarum 2012 v.34 no.6 pp. 2057-2068
C3 plants, C4 plants, Salsola, carbon, chlorophyll, electron transfer, fluorescence, gas exchange, habitats, isotopes, leaf water potential, leaves, photosynthesis, transpiration, water use efficiency, xerophytes
C3 desert plant Reaumuria soongorica (RS-C3) and C4 desert plant Salsola passerina (SP-C4) may exist either in individual or in associated communities. Carbon isotope composition, leaf water potential, gas exchange and chlorophyll fluorescence characteristics of the individual and associated communities were compared with reveal, whether the associated growth represent an advantage under harsh habitat. The results showed that the δ13C values of leaves of RS-C3 and SP-C4 across different habitats fluctuated, respectively, from -24 to -27 ‰ and from -14 to -16 ‰. Leaf water potential of RS-C3 was lower than SP-C4 all day long, growing either individually or associated with the C3 plant. When associated with the C4 plant, the net photosynthetic rate of the RS-C3 increased, and the photosynthetic rate of the partner SP-C4 decreased. The transpiration rates of the associated RS-C3 and SP-C4 were both lower than in their individual colonies. In associated communities, in RS-C3, the maximal photochemical efficiency, the effective photochemical efficiency, the relative electron transport rate, the photochemical quenching of PS II increased, and the non-photochemical quenching of PS II decreased; all these parameters changed oppositely in the SP-C4 plant. This shows that, in the associated community, the C4 plants might facilitate adaptation of the RS-C3, while SP-C4 plant can adapt to the harsh environment through their own specialties. The association favored the expression of natural photosynthetic characteristics and survival of RS-C3, while retarded the growth of SP-C4. Associated growth decreases the transpiration rate of the whole community; it is conducive to improve its water use efficiency. © 2012 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.