Changes in ¹³C/¹²C of oil palm leaves to understand carbon use during their passage from heterotrophy to autotrophy

Abstract

The carbon isotope composition of leaf bulk organic matter was determined on the tropical tree Elaeis guineensis Jacq. (oil palm) in North Sumatra (Indonesia) to get a better understanding of the changes in carbon metabolism during the passage from heterotrophy to autotrophy of the leaves. Leaf soluble sugar (sucrose, glucose and fructose) contents, stomatal conductance and dark respiration, as well as leaf chlorophyll and nitrogen contents, were also investigated. Different growing stages were sampled from leaf rank -6 to rank 57. The mean values for the delta(13)C of bulk organic matter were -29.01 +/- 0.9 per thousand for the leaflets during the autotrophic stage, -27.87 +/- 1.08 per thousand for the petioles and -28.17 +/- 1.09 per thousand for the rachises, which are in the range of expected values for a C(3) plant. The differences in delta(13)C among leaf ranks clearly revealed the changes in the origin of the carbon source used for leaf growth. Leaves were (13)C-enriched at ranks below zero (around -27 per thousand). During this period, the 'spear' leaves were completely heterotrophic and reserves from storage organs were mobilised for the growth of these young emerging leaves. (13)C-depletion was then observed when the leaf was expanding at rank 1, and there was a continuous decrease during the progressive passage from heterotrophy until reaching full autotrophy. Thereafter, the delta(13)C remained more or less constant at around -29.5 per thousand. Changes in sugar content and in delta(13)C related to leaf ranks showed an interesting similarity of the passage from heterotrophy to autotrophy of oil palm leaves to the budburst of some temperate trees or seed germination reported in the literature.

Changes inδ13C of dark respired CO2and organic matter of different organs during early ontogeny in peanut plants

“…Email: jaleh.ghashghaie@u-psud.fr given organ, for example, leaf lamina were shown to be 13 C-depleted compared with leaf ribs in different herbs and woody species (see [5] and references therein). Heterotrophic leaves (about to be emerged and not yet green) are 13 C-enriched compared with green autotrophic leaves as well [6,7]. It is concluded that fractionation mechanisms do likely occur after net CO 2 fixation in the leaves (i.e.…”

Opposite carbon isotope discrimination during dark respiration in leaves versus roots – a review

“…A difference in carbon isotope composition is also observed between different tissues of a given organ; for example, leaf lamina were shown to be 13 C‐depleted compared with leaf ribs in different herbs and woody species (Badeck et al ., and references therein). Heterotrophic leaves (before photosynthetic onset) are 13 C‐enriched compared with green autotrophic leaves as well (Bathellier et al ., ; Lamade et al ., ). It is concluded that fractionation mechanisms do probably occur after net CO 2 fixation in the leaves, leading to the observed 13 C differences between autotrophic and heterotrophic tissues/organs.…”

Carbon allocation and carbon isotope fluxes in the plant-soil-atmosphere continuum: a review

“…However, distinct differences in the use of recent vs. stored C for radial growth have been documented for deciduous trees, with some species incorporating negligible amounts of reserves . During summer, photosynthates are allocated mainly above ground (Mordacq et al, 1986;Olsrud and Christensen, 2004), supplying shoot elongation (Schier, 1970;Hansen and Beck, 1994), radial growth (Gordon and Larson, 1968), further foliage development (Dickson et al, 2000;Lamade et al, 2009) and flowering and fruiting (Mor and Halevy, 1979;Hoch and Keel, 2006). Possibly as a result of rapid mixing between old and new C (Keel et al, 2007) there is a carryover of stores for wood growth in most species (Kagawa et al, 2006b;Keel et al, 2006;von Felten et al, 2007;Palacio et al, 2011), which may impair the use of isotope tree-ring data as proxy for environmental processes.…”