Tissue chemistry and carbon allocation in seedlings of Pinus palustris subjected to elevated atmospheric CO2 and water stress

Abstract

Summary Longleaf pine (Pinus palustris Mill.) seedlings were grown in 45-1 pots and exposed to ambient or elevated (365 or 730 jamol CO 2 mo1-1 ) CO2 concentration in open-top chambers for 20 months. Two water-stress treatments (target values of -0.5 or -1.5 MPa xylem pressure potential) were imposed 19 weeks after initiation of the study. At harvest, tissues (needles, stems, taproots, coarse roots, and fine roots) were analyzed for carbon (C), nitrogen (N), nonpolar extractives (fats, waxes, and oils), nonstructural carbohydrates (sugars and starch), structural components (cellulose and lignin), and tannins. The greatest dry weights and lowest N concentrations occurred in tissues of plants grown at elevated CO 2 or with adequate water.Although allocation of C fractions among tissues was generally unaffected by treatments, concentrations of the analyzed compounds were influenced by treatments in needles and taproots, but not in stems and lateral roots. Needles and taproots of plants exposed to elevated CO 2 had increased concentrations of nonstructural carbohydrates. Among plant tissues, elevated CO2 caused reductions in structural C concentrations and foliar concentrations of fats, waxes and oils.

Drought effects on composition and yield for corn stover, mixed grasses, andMiscanthusas bioenergy feedstocks

“…Another possible contribution to the increased extractives is an accumulation of fats, waxes, and oil, which are also components included in the extractives values. Previous work on longleaf pine seedlings demonstrated that plants stressed for water had elevated fats, waxes, and oil concentrations [41]. As the precipitation was much lower and temperatures were elevated in 2012 compared with 2010, these compositional trends are most likely associated with the drought rather than the differences in hybrid (Figure 3).…”

Evergreen Quercus aquifolioides remobilizes more soluble carbon components but less N and P from leaves to shoots than deciduous Betula ermanii at the end-season

“…that plants grown with low water availability had higher tissue NSC concentrations, because drought may restrict plant growth rather than reduce the rate of photosynthesis, leading to an accumulation of NSC (Runion et al 1999). Contradicting results on the variation of NSC, sugars, and starch concentrations with elevation are reported in the literature (increase, steady, decrease -Hoch & Körner 2003, Li et al 2008a, Gruber et al 2011).…”

Effects of AtmosphericCO2Enrichment on SoilCO2Efflux in a Young Longleaf Pine System

“…Plant tissue produced under high CO 2 often has higher C : N ratios [13,14] and may be structurally different, with alterations in leaf anatomy [15] and epicuticular waxes [16,17]. Plants grown under elevated CO 2 may also exhibit altered tissue chemistry, including lower N concentrations [18,19], higher concentrations of carbohydrates [19,20], and increased levels of defense compounds such as phenolics [21,22].…”