caa a22 4500 605480885 CHVBK 20210128100418.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s11099-015-0143-0 doi (NATIONALLICENCE)springer-10.1007/s11099-015-0143-0 Photosynthetic adaptation and survival strategy of Duvalia velutina in an extremely arid environment [Elektronische Daten] [Y. Masrahi, T. Al-Turki, O. Sayed] Leafless Duvalia velutina Lavranos (Apocynaceae) is an arido-active stem succulent common in the arid region southwest of the Arabian Peninsula. This region is characterized by a short wet season with erratic rainfall and a long dry season with high temperature and high irradiance. We investigated the survival strategy of D. velutina by studying nurse association, gas exchange, and chlorophyll fluorescence. Results showed that D. velutina exhibited the strict nurse association with shade for protection against heat and high irradiance. Results also showed that D. velutina is an obligate CAM plant with ample physiotypic plasticity involving a shift to CAM-idling under prolonged drought. Chlorophyll fluorescence measurements revealed water stress-induced reduction of PSII activity occurring in concomitance with a marked rise of nonphotochemical quenching and chlorenchyma anthocyanin content. These results reflected photoprotective capacity involving nonradiative excess energy dissipation and antioxidative attributes. We concluded that the complex survival strategy of D. velutina in its natural arid habitat includes a multifaceted interplay of nurse association, physiotypic plasticity, and photoprotective mechanisms. The Institute of Experimental Botany, 2015 chlorophyll fluorescence nationallicence CAM nationallicence CAM-idling nationallicence drought nationallicence Duvalia velutina nationallicence nurse association nationallicence photoprotection nationallicence C i : intercellular CO2 concentration nationallicence Chl : chlorophyll nationallicence Fv/Fm : maximal photochemical efficiency of PSII antenna nationallicence g s : stomatal conductance nationallicence NPQ : nonphotochemical quenching nationallicence P N : photosynthetic rate nationallicence ΦPSII : PSII quantum yield nationallicence Masrahi Y. Faculty of Science, Jazan University, 45142, Jazan, Saudi Arabia aut Al-Turki T. King Abdul Aziz City for Science and Technology, 11442, Riyadh, Saudi Arabia aut Sayed O. Faculty of Science, Jazan University, 45142, Jazan, Saudi Arabia aut Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/4(2015-12-01), 555-561 0300-3604 53:4<555 2015 53 11099 https://doi.org/10.1007/s11099-015-0143-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11099-015-0143-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Masrahi Y. Faculty of Science, Jazan University, 45142, Jazan, Saudi Arabia aut NATIONALLICENCE 700 1- Al-Turki T. King Abdul Aziz City for Science and Technology, 11442, Riyadh, Saudi Arabia aut NATIONALLICENCE 700 1- Sayed O. Faculty of Science, Jazan University, 45142, Jazan, Saudi Arabia aut NATIONALLICENCE 773 0- Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/4(2015-12-01), 555-561 0300-3604 53:4<555 2015 53 11099