Study of functional and physiological response of co-occurring shrub species to the Mediterranean climate

Abstract

The Mediterranean basin is characterised by increasingly dry summers and the study of the adaptive traits developed by plants living in this stressful environment is of great interest, also in relation to climate projections for this area.Cistus monspeliensis, Myrtus communis and Phillyrea angustifolia are three co-occurring shrubs typical of the Mediterranean maquis. Their functional and physiological parameters were studied in spring, summer and autumn in order to highlight adjustments of these traits and to test eventual different adaptive strategies.Soil and leaf chemical characteristics were determined in the different seasons. Leaf area, specific leaf area, leaf dry matter content, succulence index, pigment contents hydric status and main markers of oxidative stress and antioxidant response were detected.The stressful summer season induced disturbance in hydric balance, decrease in succulence index and chlorophyll content and high contents of hydrogen peroxide. Thanks to higher enzymatic activities and total glutathione content, in the two evergreen species M. communis and P. angustifolia oxidative damage remained at levels equal to or lower than the other seasons. Only in the semideciduous C. monspeliensis both functional and biochemical traits showed a higher stress condition in summer. The higher stability of functional traits in the two evergreen species may be explained by the sclerophyllous nature of their leaves. Four environmental variables – Tmax, Tmin, soil conductivity and organic matter – mostly influenced NMDS segregation of these species.

Pasta Fortification with Leaves of Edible Wild Plants to Lower the P Glycaemic Index of Handmade Fresh Noodles

“…The environment and climatic conditions influence pigment content. For example, greater amounts of pigment are measured in plants growing in shady conditions [26]. Pigments are sensitive to temperature and light, nevertheless, consistent results have been recorded in other studies [27].…”

Differential responses of Hollyhock (Alcea rosea L.) varieties to salt stress in relation to physiological and biochemical parameters

“…Such a decrease in chlorophyll content may be as a result of a disorganization of thylakoid membranes, with more degradation than synthesis of chlorophyll via the formation of photolytic enzymes like chlorophyllase, as well as damaging the photosynthetic apparatus 32 . A similar observed decrease in chlorophyll content under salt stress, has been reported to be due to pigment photo oxidation 33 , loss of chlorophyll membranes, distortion of the lamella vesiculation as well as excessive swelling 34 and damage of chlorophyll by ROS 35 . It was suggested that the rate of photosynthesis was directly related to chlorophyll content and chlorophyll degradation leads to a reduction of the photosynthetic rate.…”

Stress markers and physiochemical responses of the Mediterranean shrub Phillyrea angustifolia under current and future drought and ozone scenarios

“…Plant resistance to oxidative stress also depends on leaf biochemical traits which are crucial for avoiding and preventing oxidative stress (Sharma et al, 2012). A plethora of studies have described how antioxidant concentrations and antioxidant enzymatic activities are modified under abiotic stresses, also in P. angustifolia plants subjected to individual and combined stresses (e. g., drought, O 3 , high temperature; Munné-Bosch and Peñuelas, 2003;Peñuelas et al, 2004;Ciccarelli et al, 2019). Carotenoids not only absorb blue light used for photosynthesis (as previously discussed), but they are also involved in energy dissipation by heat through the xanthophyll cycle, quenching 1 O 2 formed during photo-oxidation, abscisic acid biosynthesis, and regulation of thylakoid membrane fluidity (Havaux et al, 2005).…”