Osmotic adjustment, stomata morphology and function show contrasting responses to water stress in mesic and hydric grasses under elevated CO2 concentration

Author(s)
Mwendia, S W
Yunusa, I A M
Sindel, B M
Whalley, R D B
Bruhl, J J
Publication Date
2019-01-30
Abstract
<p>The physiological response of two species of grasses with C<sub>3</sub> and C<sub>4</sub> mechanisms syndromes, Napier grass (<i>Pennisetum purpureum</i> Schumach × <i>Pennisetum glaucum</i> (L.) R. Br) and hydric common reed grass (<i>Phragmites australis</i> (Cav.) Trin. Ex Steud) was examined under ambient (aCO<sub>2</sub>) and elevated CO<sub>2</sub> (eCO<sub>2</sub>), in combination with water and temperature stress treatments. Under eCO<sub>2</sub> and subjected to water and temperature stress, the Napier grass maintained higher daytime leaf water potential (LWP) by reducing transpiration (<i>E</i>) and executing larger osmotic adjustment (OA) at an average of 0.85 MPa compared with 0.42 MPa for common reed; carbon assimilation (<i>P</i><sub>N</sub>) was thus higher for the Napier grass. Under aCO<sub>2</sub> and low temperature, water stress induced no significant differences in OA between the grasses, but Napier grass still had higher <i>P</i><sub>N</sub> than that of common reed. Recovery in LWP and <i>P</i><sub>N</sub> following re-watering of water-stressed plants was more rapid in Napier grass than that in the common reed; the former had also higher water-use efficiency due to its low specific water use (water use/leaf area) that was just a fraction (less than 6%) that of the common reed. Exposure of common reed to eCO<sub>2</sub> reduced stomata number, but increased it in the Napier grass, especially when subjected to water stress and high temperature. Exposure to eCO<sub>2</sub> enhanced OA capacity and <i>E</i> control in Napier grass resulting in superior physiological profile over the common reed subjected to water and heat stress.</p>
Citation
Photosynthetica, 57(1), p. 121-131
ISSN
1573-9058
0300-3604
Link
Publisher
Akademie Ved Ceske Republiky, Ustav Experimentalni Botaniky (Academy of Sciences of the Czech Republic, Institute of Experimental Botany)
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
Title
Osmotic adjustment, stomata morphology and function show contrasting responses to water stress in mesic and hydric grasses under elevated CO2 concentration
Type of document
Journal Article
Entity Type
Publication

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