Water deficits are more important in delaying growth than in changing patterns of carbon allocation in Eucalyptus globulus

Abstract

Potted cuttings of three Eucalyptus globulus Labill. clones (AR3, CN44, MP11) were either well watered or subjected to one of two soil water deficit regimes for six months in a greenhouse. Reductions in lateral branching, leaf production and leaf expansion were the leading contributors to the large differences observed in biomass production between well-watered and water-stressed plants. Although no significant differences among clones were observed in dry matter accumulation or in the magnitude of the response to soil water deficits, sensitivity of lateral branching, leaf initiation and whole-plant foliage to water stress was significantly lower in CN44 than in AR3 and MP11. When the confounding effect of differences in plant size resulting from the different watering regimes was removed, allometric analysis indicated that the genotypes differed in biomass allocation patterns. In addition to a drought-induced reduction in leaf number, water deficits also resulted in smaller leaves because leaf expansion was inhibited during dehydration events. Resumption of leaf expansion following stress relief occurred in all of the clones, but was particularly evident in severely stressed plants of Clone AR3, possibly as a result of the osmotic adjustment observed in this genotype.

Arugula production as a function of irrigation depths and potassium fertilization

“…Under water deficit condition, there is a restriction to biomass accumulation, which damages the number of leaves both in the initial and later stages, limiting the dimension of individual leaves and, consequently, total leaf area, number and growth rates of branches and stem growth (Osório et al, 1998).…”

Physiological and growth responses of Populus davidiana ecotypes to different soil water contents

“…WUE seems generally to have a high correlation with plant growth, however, the relationship may be postive or negative. Increasing plant WUE has been shown to either increase or decrease biomass productivity (Cregg, 1994;Leroux et al, 1996;Osorio et al, 1998;Li et al, 2000). When water is limited, plants that use water more efficiency by producing greater biomass for a given quantity of water transpired would grow more rapidly, resulting in a positive correlation between WUE and productivity.…”

Adaptive diversity in Castanea sativa Mill. half-sib progenies in response to drought stress

“…In order to withstand drought, trees have developed diverse mechanisms, the cost of which may differ in terms of productivity (Ludlow, 1989). Morphological and growth responses to drought stress include reductions in total dry weight, in the number of lateral branches, in leaf production and in the expansion of both leaves and roots (Osorio et al, 1998). Plants adapt to drought by elongating and expanding their root systems and, in addition, severe drought appears to inhibit the growth of branches more severely than that of roots (Saab et al, 1990).…”