Growth, photosynthesis, and stomatal conductance in Gutierrezia sarothrae associated with hydraulic conductance and soil water extraction by deep roots
Citation
Wan, Changgui, Sosebee, Ronald E, and McMichael, Bobby L, Growth, photosynthesis, and stomatal conductance in Gutierrezia sarothrae associated with hydraulic conductance and soil water extraction by deep roots: .
Summary
We hypothesize that predominance of Gutierrezia sarothrae in the rangeland plant community depends on its ability to take up water more effectively from soil depths below 30 cm. Gutierrezia seedlings grown in 30-cm-deep pots were allowed to develop deep lateral roots out of pots into subsoil. The deep laterals were then excised and photosynthesis and stomatal conductance of the test plants measured before and after root pruning. Photosynthesis (A) and stomatal conductance (g) were at least 49% greater (P < .05) before than after root pruning. Photosynthesis and g were more affected by the removal of four deep roots 30 cm below the surface than by the removal of four shallow roots in the top 30 cm of soil. The soil water extraction [...]
Summary
We hypothesize that predominance of Gutierrezia sarothrae in the rangeland plant community depends on its ability to take up water more effectively from soil depths below 30 cm. Gutierrezia seedlings grown in 30-cm-deep pots were allowed to develop deep lateral roots out of pots into subsoil. The deep laterals were then excised and photosynthesis and stomatal conductance of the test plants measured before and after root pruning. Photosynthesis (A) and stomatal conductance (g) were at least 49% greater (P < .05) before than after root pruning. Photosynthesis and g were more affected by the removal of four deep roots 30 cm below the surface than by the removal of four shallow roots in the top 30 cm of soil. The soil water extraction patterns in Gutierrezia plants grown in 60-cm soil columns were determined for the upper 30 cm and 30 to 60 cm of soil. Water extraction was significantly greater (P < .05) from the wetter, lower section of the soil column than from the drier, upper column. Higher photosynthesis (138%, P < .05), transpiration (154%, P < .01), stomatal conductance (223%, P < .01), and canopy development (340%, P < .05) were observed in plants with deep roots growing beyond the pots than well-watered, pot-grown plants without deep roots. This was related to higher hydraulic conductance, which in turn appeared enhanced by the greater ratio of deep root length to total root length. Stomatal conductance, photosynthesis, and canopy development in Gutierrezia may be regulated by hydraulic capacity, which is determined largely by deep root development.
Published in International Journal of Plant Sciences, volume 154, issue 1, on pages 144 - 151, in 1993.
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Growth, photosynthesis, and stomatal conductance in Gutierrezia sarothrae associated with hydraulic conductance and soil water extraction by deep roots
