Functional anatomy of juvenile wood of Pinus taeda L: genotypic variability and anatomical plasticity in response to water deficit
Pinus taeda L. achieves high growth rates in the Northeastern region of Argentina, South-America. However, according to that reported for other tree species, both gymnosperms and broadleaves, there may be a tradeoff between productivity and resistance to water deficit, mediated by differences in wood anatomical characteristics that determine the efficiency of water conduction -driving maximum growth- and xylem vulnerability to cavitation – associated to resistance to water deficit. The objective of this study was to analyze the relationships between wood anatomy, wood density and functionality in different genotypes of P. taeda of contrasting growth rate (high (AC) and low (BC)) under optimal and deficit water conditions. Under greenhouse conditions, two treatments of water deficit (moderate and severe) and a control were applied. Measurements of lumen diameter and wall thickness of tracheids, proportion of early and latewood, and wood density were carried out. Curves describing vulnerability to cavitation and estimation of the theoretical specific hydraulic conductivity (ksT) were performed. Genotypes differed in their growth (AC>BC) under optimal water conditions, presenting no significant differences in the morphometry of individual cells but differences in the proportion of early and latewood. Genotype BC1 was the only presenting a lower vulnerability to cavitation (P50 = -2.1 vs. -1.7 Mpa than the other ones, p <0.05). Under water deficit the cell level variables were unchanged, however latewood proportion did increase with no significant impact on ksT. We concluded that at the xylem level, the proportion of early and latewood within the growth ring is the most variable trait both genotypic and phenotypically in response to water deficit. No tradeoff between xylem efficiency and safety was observed in the studied genotypes.
| Main Authors: | , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata
2018
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| Online Access: | https://revistas.unlp.edu.ar/revagro/article/view/6177 |
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