Physiological Responses of Handeliodendron bodinieri (Levl.) Rehd. to Exogenous Calcium Supply under Drought Stress

Abstract

The soils in karst regions, with carbonate rocks as the background material, are characterized by two main factors, drought and high calcium levels. Handeliodendron bodinieri (Levl.) Rehd is an endemic plant species in this area of China. However, few studies have been carried out on the adaptation mechanism of H. bodinieri to drought and high calcium soil. To reveal the physiological responses of H. bodinieri to exogenous calcium under drought stress, 10% PEG-6000 was used to simulate drought stress, and the effects of exogenous calcium at different concentrations on the physiology of H. bodinieri seedlings under drought stress were studied. The results showed that drought stress significantly reduced the relative water content and water potential of H. bodinieri seedlings. Malondialdehyde (MDA) content, O2− and H2O2 production rates significantly increased under drought stress. The addition of exogenous calcium significantly reduced MDA content and O2− and H2O2 production rates. Moreover, peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbic acid peroxidase (APX) and glutathione peroxidase (GPX) activities increased significantly under drought stress. At the same time, the accumulation of osmotic regulators such as soluble sugar, betaine and free proline also increased significantly. The addition of exogenous calcium further increased the activity of antioxidant enzymes and the accumulation of osmotic regulatory substances. Consequently, the oxidative stress and osmotic stress induced by drought decreased. Finally, exogenous calcium enhanced the photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of H. bodinieri under drought stress and significantly improved water use efficiency (WUE). This study confirmed that the application of exogenous calcium can enhance the water condition, photosynthetic capacity, osmotic regulation and antioxidant capacity of H. bodinieri under drought stress. Of the treatments, the 10 mmol·L−1 CaCl2 treatment is more likely to improve survival of H. bodinieri under drought tolerance. This study provides an important reference for describing the adaptation mechanism and appropriate conservation of H. bodinieri under drought and high calcium conditions.

Proline and Oxidative Metabolism in Young Pecan Trees Associated with Sulphate Accumulation

“…In contrast, when the concentration of H 2 O 2 is increased in Panax ginseng seedlings, greater tolerance to salinity has been demonstrated by the activities of CAT and GP [42]. This behavior may be linked to the homeostasis generated by the specific production of H 2 O 2 and the activities of the antioxidant systems [9]. This contrasts with our observations for GP in leaflets suffering 'moderate' and 'severe' damage.…”

“…The presence of sulphates in the soil significantly impacted the production of H 2 O 2 in pecan nut leaflets (Table 3). One of the physiological responses to stomatal closure and low CO 2 availability is associated with the production of H 2 O 2 for the oxygenation of RuBisCO and the increase in photorespiration [9]. In this sense, the behavior in the production of H 2 O 2 is associated with the activity of SOD through the Haber Weiss reaction [13,39].…”

“…Other factors that contribute to the accumulation of salts in soils are excessive applications of chemical fertilizers and inappropriate tillage, especially in clay soils with poor drainage [4]. Pecan trees growing in soils with excessive salts show signs of distress indicated by stomatal closure, reduced vegetative growth, necrosis of leaf margins and early leaf senescence [8,9]. Consequently, the accumulation of biomass and the yield and quality of the nuts are all reduced [1].…”

Effects of drought stress and rehydration on physiological and biochemical of four oak species in China

“…Similar results were observed in Handeliodendron bodinieri (Levl.) (Leng et al 2020), Olea europaea L (Denaxa et al 2020). We also found that the SOD activity increased signi cantly at day 6.…”

Effects of ultra-dry storage on seed germination and seedling growth of <i>Handeliondendron bodinieri</i>

“…2) including, Guangxi, Guizhou, and Yunnan (Cao et al 2008;Wang et al 2008). This woody, fuel-oil plant species is excellent for rock desertification control (Guo et al 2019a;Guo et al 2019b;Leng et al 2020). However, due to its low seed germination rate, its vulnerability to insects, slow growth, shallow root system, and to the destruction of its habitat, it is currently on the verge of extinction and is therefore listed as a national, first-level protection species (He et al 2012).…”