Stress-induced changes in carbon allocation among metabolite pools influence isotope-based predictions of water use efficiency in Phaseolus vulgaris

2016 ◽  
Vol 43 (12) ◽  
pp. 1149 ◽  
Author(s):  
Erin Lockhart ◽  
Birgit Wild ◽  
Andreas Richter ◽  
Kevin Simonin ◽  
Andrew Merchant

Understanding how major food crops respond to environmental stress will expand our capacity to improve food production with growing populations and a changing climate. This study uses chemical and physiological adaptations to heat, water deficit and elevated light stresses in Phaseolus vulgaris L. to identify changes in carbon (C) allocation that, combined with post-photosynthetic fractionation of C isotopes, influences water use efficiency (WUE) predictions. The chemical stress response was explored through changes in C allocation to the carbohydrate and cyclitol pools using GC–triple quadrupole MS. Carbon allocation to the sucrose pool fluctuated significantly among treatments, and the putative osmolytes and osmoprotectants (myo-inositol and d-ononitol) accumulated under stress. Significant osmotic adjustment (P < 0.05), quantified via pressure–volume curve analysis, was detected between control and stress treatments, although this was not attributable to active accumulation of the metabolites. Compound-specific 13C isotope abundance was measured using liquid chromatography isotope ratio MS to predict intrinsic WUE. In contrast to other metabolites measured, the δ13C of the sucrose pool fluctuated according to treatment and was proportional to predicted values based upon modelled Δ13C from gas exchange data. The results suggest that the accuracy and precision of predicting WUE may be enhanced by compound-specific analysis of Δ13C and that changes in the allocation of C among metabolite pools may influence WUE predictions based upon analysis of total soluble C. Overall, the plants appeared to use a range of mechanisms to cope with adverse conditions that could be utilised to improve plant breeding and management strategies.

2005 ◽  
Vol 45 (9) ◽  
pp. 1181 ◽  
Author(s):  
G. Kaine ◽  
D. Bewsell ◽  
A. Boland ◽  
C. Linehan

Market research was conducted to develop an extension program targeting the specific irrigation management needs of growers in the stone and pome fruit industry within the Goulburn Valley, Victoria. The process of integrating market research with extension practice proved challenging, as it required the development of an extension program that was fundamentally different from what was originally envisaged. However, it was essential to achieve this integration in order to meet the original objectives for the extension program as set by the funding body. We found, in most cases, that the motivation for stone and pome fruit growers in the Goulburn Valley to change orchard irrigation management practices was not because they needed to save water, or to increase water use efficiency. Instead, growers were changing practices in order to save time irrigating, improve the scope for managerial flexibility in the orchard, or when redeveloping their orchard to a closer planting design. These findings suggest that growers in the Goulburn Valley are more likely to respond to an extension program consistent with these motivations rather than a program promoting water use efficiency.


2009 ◽  
Vol 101 (3) ◽  
pp. 460-468 ◽  
Author(s):  
R. L. Baumhardt ◽  
S. A. Staggenborg ◽  
P. H. Gowda ◽  
P. D. Colaizzi ◽  
T. A. Howell

HortScience ◽  
2016 ◽  
Vol 51 (6) ◽  
pp. 684-689 ◽  
Author(s):  
Youssef Rouphael ◽  
Giampaolo Raimondi ◽  
Rosanna Caputo ◽  
Stefania De Pascale

Implementing nutrient management strategies in soilless culture, which improve water use efficiency (WUE) and limit the loss of eutrophying elements without affecting crop performance, is a priority for the floriculture industry. The aim of the current research was to assess the effect of two nutrient management strategies, based on electrical conductivity (EC) or nitrate-nitrogen (N-NO3−) concentration control on plant growth, ornamental quality, plant–water relations, mineral composition, and WUE of greenhouse Hippeastrum grown in semiclosed soilless system. The recirculating nutrient solution was discharged whenever a threshold EC value of 3.0 dS·m−1 was reached (EC-based strategy), or when N-NO3− concentration decreased below the limit of 1.0 mol·m−3 (nitrate-based strategy). There were no significant differences in terms of plant growth parameters, stomatal resistance, leaf water relations, and macronutrient composition in plant tissues between the two nutrient management strategies. In the EC- and the nitrate-based strategies, the recirculating nutrient solution was flushed 10 and 5 times, respectively. The water loss (WL) and the total water use (Wuse) in the EC-based strategy were significantly higher by 261.1% and 61.5%, respectively, compared with the N-NO3−-based strategy. In contrast with the EC-based strategy, the adoption of the N-NO3−-based strategy significantly minimized the nitrate, phosphate, and potassium emissions to the environment. The effective WUE of the system (WUES) recorded in the N-NO3−-based strategy was higher by 55.9% compared with the one recorded with the EC-based strategy.


Author(s):  
Farah Riaz ◽  
Muhammad Riaz ◽  
Muhammad Saleem Arif ◽  
Tahira Yasmeen ◽  
Muhammad Arslan Ashraf ◽  
...  

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1238 ◽  
Author(s):  
Jennifer Wilker ◽  
Sally Humphries ◽  
Juan Rosas-Sotomayor ◽  
Marvin Gómez Cerna ◽  
Davoud Torkamaneh ◽  
...  

Common bean (Phaseolus vulgaris L.) provides critical nutrition and a livelihood for millions of smallholder farmers worldwide. Beans engage in symbiotic nitrogen fixation (SNF) with Rhizobia. Honduran hillside farmers farm marginal land and utilize few production inputs; therefore, bean varieties with high SNF capacity and environmental resiliency would be of benefit to them. We explored the diversity for SNF, agronomic traits, and water use efficiency (WUE) among 70 Honduran landrace, participatory bred (PPB), and conventionally bred bean varieties (HON panel) and 6 North American check varieties in 3 low-N field trials in Ontario, Canada and Honduras. Genetic diversity was measured with a 6K single nucleotide polymorphism (SNP) array, and phenotyping for agronomic, SNF, and WUE traits was carried out. STRUCTURE analysis revealed two subpopulations with admixture between the subpopulations. Nucleotide diversity was greater in the landraces than the PPB varieties across the genome, and multiple genomic regions were identified where population genetic differentiation between the landraces and PPB varieties was evident. Significant differences were found between varieties and breeding categories for agronomic traits, SNF, and WUE. Landraces had above average SNF capacity, conventional varieties showed higher yields, and PPB varieties performed well for WUE. Varieties with the best SNF capacity could be used in further participatory breeding efforts.


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