Interactions between water deficit, ABA, and provenances in Picea asperata

Abstract

The effects of exogenous abscisic acid (ABA) on the acclimation of Picea asperata to water deficit were investigated in two populations originating from wet and dry climate regions of China. Exogenous ABA was sprayed onto the leaves, and changes in plant growth and structure, gas exchange, water use efficiency (WUE), endogenous ABA content, and antioxidant enzyme levels were monitored. The results demonstrated that ABA application affected the two P. asperata populations in different ways during the water deficit. ABA application resulted in significantly lower CO(2) assimilation rates (A) under water deficit in plants from the wet climate population, whereas there were no significant changes in this parameter in the dry climate population. On the other hand, ABA application significantly decreased the dry shoot biomass, stomatal conductance (g(s)), transpiration rate (E), and malondialdehyde (MDA) content, and it significantly increased the leaf mass per area (LMA), root/shoot ratio (Rs), fine root/total root ratio (Ft), WUE, ABA content, and the superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) activities under water-deficit conditions in the dry climate population, whereas ABA application did not significantly affect these parameters in the wet climate population. The results clearly demonstrated that sensitivity to an exogenous ABA application is population-dependent in P. asperata. Direct evidence is presented that variation in physiological mechanisms rather than different rates of ABA absorption explain the population differentiation in the sensitivity to exogenous ABA, and that the physiological basis for the amplified response to water deficit caused by exogenous ABA, present mainly in the dry climate population, is related to internal ABA accumulation. These results provide evidence for adaptive differentiation between populations of P. asperata, and they support the expected relationship between environmental heterogeneity and the magnitude of plastic responses in plant populations.

Effect of drought and ABA on growth, photosynthesis and antioxidant system of Cotinus coggygria seedlings under two different light conditions

“…Furthermore, the treatments by exogenous ABA and D + ABA significantly decreased A, g s and E under FL. Thus, our results are consistent with previous studies showing that ABA plays a critical role in the negative regulation of stomata (Dodd, 2003) and has a predictable negative relationship with g s (Duan et al, 2007). However, modes of stomatal behavior are too complex to be explained by ABA alone (Liang and Zhang, 1999), and the sensitivity of stomata to ABA varies considerably according to environmental factors, such as temperature, leaf water potential and atmospheric [CO 2 ], ionic composition of epidermal strip, incubation solutions and the presence of other hormones (Dodd et al, 1996).…”

“…Abscisic acid (ABA) is an essential mediator in triggering the plant responses to many environmental stresses (Zhu, 2002;Lu et al, 2009). ABA can increase the activity of the reactive oxygen species (ROS) scavenging enzymes, superoxide dismutase (SOD) and catalase (CAT), and reduce malondialdehyde (MDA) formation (Lei et al, 2006;Duan et al, 2007). On the other hand, shade treatment can affect the endogenous hormone levels (Huang et al, 2008).…”

Water use efficiency of marandu palisadegrass as affected by nitrogen and sulphur rates

“…Therefore, reduction in water uptake by plants contributes to cell dehydration and adaptive changes in plant growth and physio-biochemical processes, such as changes in plant structure, growth rate, tissue osmotic potential and antioxidant defenses (DUAN et al, 2007). According to Volenec and Nelson (2003), low water availability in soil causes the plant stomata to close, reducing CO 2 assimilation, transpiration, leaf expansion and allocation of photo assimilates to organs.…”

Soil cadmium toxicity and nitrogen deposition differently affect growth and physiology in Toxicodendron vernicifluum seedlings

“…The mixture was heated in boiling water for 15 min, and then quickly cooled on ice. After centrifugation at 12,000g for 10 min, the absorbance of the supernatant was measured at 450, 532 and 600 nm to determine the MDA content (Duan et al 2007). …”