scholarly journals Legumes are different: Leaf nitrogen, photosynthesis, and water use efficiency

2016 ◽  
Vol 113 (15) ◽  
pp. 4098-4103 ◽  
Author(s):  
Mark Andrew Adams ◽  
Tarryn L. Turnbull ◽  
Janet I. Sprent ◽  
Nina Buchmann

Using robust, pairwise comparisons and a global dataset, we show that nitrogen concentration per unit leaf mass for nitrogen-fixing plants (N2FP; mainly legumes plus some actinorhizal species) in nonagricultural ecosystems is universally greater (43–100%) than that for other plants (OP). This difference is maintained across Koppen climate zones and growth forms and strongest in the wet tropics and within deciduous angiosperms. N2FP mostly show a similar advantage over OP in nitrogen per leaf area (Narea), even in arid climates, despite diazotrophy being sensitive to drought. We also show that, for most N2FP, carbon fixation by photosynthesis (Asat) and stomatal conductance (gs) are not related to Narea—in distinct challenge to current theories that place the leaf nitrogen–Asat relationship at the center of explanations of plant fitness and competitive ability. Among N2FP, only forbs displayed an Narea–gs relationship similar to that for OP, whereas intrinsic water use efficiency (WUEi; Asat/gs) was positively related to Narea for woody N2FP. Enhanced foliar nitrogen (relative to OP) contributes strongly to other evolutionarily advantageous attributes of legumes, such as seed nitrogen and herbivore defense. These alternate explanations of clear differences in leaf N between N2FP and OP have significant implications (e.g., for global models of carbon fluxes based on relationships between leaf N and Asat). Combined, greater WUE and leaf nitrogen—in a variety of forms—enhance fitness and survival of genomes of N2FP, particularly in arid and semiarid climates.

2018 ◽  
Vol 30 (2) ◽  
pp. 333-346 ◽  
Author(s):  
Andrea Giro ◽  
Antonio Ferrante

Abstract Corchorus olitorius (L.) is one of the main crops for fibre production, cultivated in tropical and subtropical environments, from Africa to Japan, across the Middle East and India. In developing countries, the leaves are used as a medicine and also as food. In this study, we evaluated the physiological responses of nine accessions of C. olitorius in order to nominate the most suitable one for introduction into southern Europe. African and Asian accessions obtained from the Leibniz Institute IPK gene bank were analysed for their photosynthetic variables and quality traits during cultivation. Accessions from Africa, in particular those from Egypt and Libya, showed higher intrinsic water-use efficiency. However, at high temperatures, the Japanese accession also showed a high level of water-use efficiency, as evidenced by the high carbon fixation rate. Chinese and Indian accessions showed a reduction in growth performance, although a high concentration of antioxidants in the leaves and biomass accumulation have been reported in those accessions. C. olitorius demonstrated an intrinsic attitude to adaptation; according to their subtropical origin, all of the plants grew at sub-optimal status (Fv/Fm). These data, however, do not seem to compromise the potential of these plants as a crop for growing in southern Europe. Moreover, their introduction can be based solely on their biochemical quality traits.


2018 ◽  
Vol 76 (2) ◽  
pp. 115-130 ◽  
Author(s):  
G Guo ◽  
K Fang ◽  
J Li ◽  
HW Linderholm ◽  
D Li ◽  
...  

Crop Science ◽  
2002 ◽  
Vol 42 (1) ◽  
pp. 122 ◽  
Author(s):  
A. G. Condon ◽  
R. A. Richards ◽  
G. J. Rebetzke ◽  
G. D. Farquhar

2018 ◽  
Vol 36 (1) ◽  
pp. 7-13
Author(s):  
Melissa C. Smith ◽  
Richard N. Mack

Abstract Suitable plant water dynamics and the ability to withstand periods of low moisture input facilitate plant establishment in seasonally arid regions. Temperate bamboos are a major constituent of mixed evergreen and deciduous forests throughout temperate East Asia but play only an incidental role in North American forests and are altogether absent in the Pacific Northwest forest. Many bamboo species are classified as mesic or riparian, but none are considered drought tolerant. To assess their ability to withstand low water, we subjected five Asian temperate and one North American temperate bamboo species to three irrigation treatments: 100%, 50%, and 10% replacement of water lost through evapotranspiration. Plants were irrigated every four days over a 31-day period. Plant response to treatments was measured with stomatal conductance, leaf xylem water potentials, and intrinsic water use efficiency (iWUE). Pleioblastus distichus and Pseudosasa japonica showed significant reductions in conductance between high and low irrigation treatments. Sasa palmata had significantly lower stomatal conductance in all treatments. Pleioblastus chino displayed significantly higher iWUE in the mid irrigation treatment and Arunindaria gigantea displayed significantly lower iWUE than P. chino and S. palmata in the low irrigation treatment. The Asian bamboo species examined here tolerate low water availability and readily acclimate to different soil moisture conditions. Index words: Temperate bamboos, irrigation response, stomatal conductance, intrinsic water use efficiency. Species used in this study: Giant Cane [Arundinaria gigantea (Walt.) Muhl.]; Pleioblastus chino (Franchet & Savatier) Makino; Pleioblastus distichus (Mitford) Nakai; Pseudosasa japonica (Makino); Sasa palmata (Bean) Nakai.


2021 ◽  
pp. 1-12
Author(s):  
R. Dietrich ◽  
F.W. Bell ◽  
M. Anand

Given the large contribution of forests to terrestrial carbon storage, there is a need to resolve the environmental and physiological drivers of tree-level response to rising atmospheric CO2. This study examines how site-level soil moisture influences growth and intrinsic water-use efficiency in sugar maple (Acer saccharum Marsh.). We construct tree-ring, δ18O, and Δ13C chronologies for trees across a soil moisture gradient in Ontario, Canada, and employ a structural equation modelling approach to ascertain their climatic, ontogenetic, and environmental drivers. Our results support previous evidence for the presence of strong developmental effects in tree-ring isotopic chronologies — in the range of −4.7‰ for Δ13C and +0.8‰ for δ18O — across the tree life span. Additionally, we show that the physiological response of sugar maple to increasing atmospheric CO2 depends on site-level soil moisture variability, with trees only in relatively wet plots exhibiting temporal increases in intrinsic water-use efficiency. These results suggest that trees in wet and mesic plots have experienced temporal increases in stomatal conductance and photosynthetic capacity, whereas trees in dry plots have experienced decreases in photosynthetic capacity. This study is the first to examine sugar maple physiology using a dendroisotopic approach and broadens our understanding of carbon–water interactions in temperate forests.


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