Water-use efficiency and carbon isotope discrimination of Acacia ampliceps and Eucalyptus camaldulensis at different soil moisture regimes under semi-arid conditions

Abstract

Acacia ampliceps Maslin and Eucalyptus camaldulensis Dehnh. were grown for one year in lysimeters at three soil moisture regimes: 100 % (well-watered), 75 % (medium-watered) and 50 % (low-watered) of total plant available water. Biomass yield of both species increased with increase in soil moisture. Water-use efficiency (WUE) of E. camaldulensis decreased and that of A. ampliceps increased markedly with decrease in available soil moisture. A. ampliceps showed 4 -5 times more biomass yield than E. camaldulensis grown at similar soil moisture. A. ampliceps showed almost 5, 9 and 12 times higher WUE than E. camaldulensis under low-, medium-and well-watered treatments, respectively. Significant negative correlation of δ 13 C with WUE (r = -0.99) was observed in A. ampliceps. In contrast, δ 13 C of E. camaldulensis showed a significant positive correlation with WUE (r = 0.82).Additional key words: biomass production, plant available soil water, transpiration efficiency.

Growth, biomass partitioning, and water-use efficiency of a leguminous shrub (Bauhinia faberi var. microphylla) in response to various water availabilities

“…The decrease in WUE of B. faberi var. microphylla seedlings under water stress, contradicts the finding with some species (Hubick et al 1986;Liu et al 2005;Maggio et al 2005), and agrees with reports on crops (Zhao et al 2004;Clavel et al 2005) and on Acacia ampliceps (Akhter et al 2005). Engelbrecht et al (2005) suggested that decreased WUE in water-stressed seedlings might be related to their root systems which are not well-established to acquire water from lower soil layers.…”

Morphological, anatomical and physiological responses of Campylotropis polyantha (Franch.) Schindl. seedlings to progressive water stress

“…Although many studies have found that the WUE of woody seedlings increased with increasing water stress (Kramer and Boyer, 1995;Yin et al, 2004;Akhter et al, 2005;Rodiyati et al, 2005;Bacelar et al, 2007;Gonzáles et al, 2008), it is still unclear about how plant WUE changes with water stress intensity. Our results along the water stress gradient with five levels provided good opportunity to explore it.…”

“…It has been found that the WUE is lower in water-stressed plants than in well-watered plants (Rodiyati et al, 2005;Bacelar et al, 2007) and believed that stomatal closure leads to a lower level of water loss per carbon assimilation, thereby improving the water-use efficiency (WUE) in water-stressed plants (Kramer and Boyer, 1995;Akhter et al, 2005;Gonzáles et al, 2008). However, the results keep to be controversial, because improving WUE may conflict with the high growth rate for many species (Hubick et al, 1986;Akhter et al, 2005;Wu et al, 2008a). The controversy focus is how plant WUE changes with water stress intensity.…”

The use of Eucalyptus in agroforestry systems of southern Rwanda : to integrate of segregate

“…Eucalyptus are known to have high water uptake which is primarily a strategy enabling them to grow even under harsh environmental conditions (Akhter et al, 2005). This high water uptake capacity enables them to outcompete other plants occurring in their vicinity.…”