RT Journal
T1 Role of photosystem II activity in salt tolerance of Panicum antidotale and Panicum turgidum: Insights from chlorophyll a fluorescence analysis on excised leaf
A1 Muhammad Javed
A1 Muhammad Iqbal
A1 Habib-ur-Rehman Athar
A1 Zafar Ullah Zafar
A1 Fahim Arshad
A1 Muhammad Ashraf
JF Journal of Animal and Plant Sciences
JO JAPS
SN 1018-7081
VO 34
IS 2
SP 387
OP 399
YR 2024
FD 2024/03/31
DO DOI https://doi.org/10.36899/JAPS.2024.2.0725
AB <p>Salt stress limits photosynthetic capacity of plants by disturbing thylakoidal reactions. Chlorophyll fluorescence measurements help in measuring the extent of photosystem-II (PSII) photodamage. <em>Panicum antidotale </em>(<em>P. antidotale</em>) and <em>Panicum turgidum</em> (<em>P. turgidum</em>) are potential fodder grasses, adapted to a variety of environmental stresses like salinity and drought. In the present study, photosynthetic performance was assessed by chlorophyll <em>a</em> fluorescence kinetic analysis of excised leaves of these two grass species immersed in varying concentration of NaCl (0, 250, 500 and 1000 m<em>M</em> NaCl) after 24 hours. Salt stress decreased chlorophyll fluorescence at J, I and P steps indicating reduced efficiency of electron transfer at PSII and from PSII to PSI. In addition, salt induced increase in Fo (11% in <em>P. antidotale</em>; 29% in <em>P. turgidum</em>) along with reduction in Fm indicated PSII photoinhibition at the donor end. Performance index (PI<sub>ABS</sub>) and quantum yield of PSII were decreased in excised leaves of both <em>Panicum</em> species with increasing salt levels. However, <em>P. antidotale</em> had greater PI<sub>ABS</sub> (1.08) and quantum yield of PSII (0.72) than in <em>P. turgidum</em> (0.47 and 0.57 respectively), which is associated with better management in absorption (0.84% as compared to 12.4% in <em>P. turgidum</em>), trapping and electron transport or better management of PSII excitation pressure under salt stress. Activity of PSII measured as PI<sub>ABS</sub> and some related JIP-test parameters can be used as potential indicators of salt tolerance. So increasing salinity stress affected primary photochemistry of PSII in excised leaves of both grass species but adverse effect of salt stress on PSII photochemistry was greater on <em>P. turgidum</em> than that of <em>P. antidotale</em>. It is suggested that assessment of fast chlorophyll <em>a</em> kinetic analysis on excised leaves of different species/cultivars may help in screening and selection for salt tolerance.</p>
K1 Salinity stress, grasses, chlorophyll fluorescence, electron transport chain, photosystem II
PB Pakistan Agricultural Scientists Forum
LK https://thejaps.org.pk/AbstractView.aspx?mid=2023-JAPS-1135