Biochemical changes in Conocarpus species under saline soils of Lal Suhanra National Park, Bahawalpur

In Pakistan, arid and semi-arid areas are more prone to limited rainfall, extensive evapo-transpiration and higher temperatures. For better understandings of current situation, a field experiment was carried out to study the morphological characteristics, biochemical responses and ionic composition of Conocarpus species (Conocarpus erectus and Conocarpus lancifolius) under saline soil conditions in Lal Suhanra National Park, Bahawalpur during 2019-21. Three sites one at normal soil (S.I) and two at different salinity levels (Medium and High Salinity) were observed in order to assess their effect on plant growth and other parameters. The data regarding physiological and biochemical parameters were recorded. Conocarpus lancifolius and Conocarpus erectus has maximum (233) mmol m-2sec-1 and (162) mmol m-2sec-1 stomatal conductance respectively. Maximum transpiration rate (4.57 MMOL M-2S-1) was observed at site-I in case of C. lancifolius, while maximum transpiration rate in case of C. erectus was (2.94 MMOL M-2S-1) at site-I. At control level, maximum photosynthetic rate was measured as (8.76 µmol m-2sec-1) in C. lancifolius and (5.59 µmol m-2sec-1) in case of C. erectus. Conocarpus species; Conocarpus lancifolius and Conocarpus erectus has maximum SOD (13.29 and 19.62) and CAT (16.48 and 42.05), and POD (14.81 and 8.81 U/mg protein) respectively. Maximum values of Na+K+ ratio in leaves (3.08), shoots (5.98) and roots (9.84) were detected at site-I in C. lancifolius. Based on statistically analyzed data, it is revealed that Conocarpus lancifolius can tolerate better salt stress as compared to Conocarpus erectus. Both species of Conocarpus can tolerate salinity up to 40 dSm-1 but growth of Conocarpus erectus is affected more as compared to Conocarpus lancifolius.