Minirhizotron imaging reveals that nodulation of field-grown soybean is enhanced by free-air CO2 enrichment only when combined with drought stress

2013 ◽  
Vol 40 (2) ◽  
pp. 137 ◽  
Author(s):  
Sharon B. Gray ◽  
Reid S. Strellner ◽  
Kannan K. Puthuval ◽  
Christopher Ng ◽  
Ross E. Shulman ◽  
...  

The rate of N2 fixation by a leguminous plant is a product of the activity of individual nodules and the number of nodules. Initiation of new nodules and N2 fixation per nodule are highly sensitive to environmental conditions. However, the effects of global environmental change on nodulation in the field are largely unknown. It is also unclear whether legumes regulate nodulation in response to environment solely by varying root production or also by varying nodule density per unit of root length. This study utilised minirhizotron imaging as a novel in situ method for assessing the number, size and distribution of nodules in field-grown soybean (Glycine max (L.) Merr.) exposed to elevated atmospheric CO2 ([CO2]) and reduced precipitation. We found that nodule numbers were 134–229% greater in soybeans grown at elevated [CO2] in combination with reduced precipitation, and this response was driven by greater nodule density per unit of root length. The benefits of additional nodules were probably offset by an unfavourable distribution of nodules in shallow, dry soil in reduced precipitation treatment under elevated [CO2] but not ambient [CO2]. In fact, significant decreases in seed and leaf nitrogen concentration also occurred only in elevated [CO2] with reduced precipitation. This study demonstrates the potential of minirhizotron imaging to reveal previously uncharacterised changes in nodule production and distribution in response to global environmental change.

jpa ◽  
1991 ◽  
Vol 4 (3) ◽  
pp. 291-293 ◽  
Author(s):  
Stephen L. Rawlins

Author(s):  
Machiel Lamers ◽  
Jeroen Nawijn ◽  
Eke Eijgelaar

Over the last decades a substantial and growing societal and academic interest has emerged for the development of sustainable tourism. Scholars have highlighted the contribution of tourism to global environmental change and to local, detrimental social and environmental effects as well as to ways in which tourism contributes to nature conservation. Nevertheless the role of tourist consumers in driving sustainable tourism has remained unconvincing and inconsistent. This chapter reviews the constraints and opportunities of political consumerism for sustainable tourism. The discussion covers stronger pockets and a key weak pocket of political consumerism for sustainable tourism and also highlights inconsistencies in sustainable tourism consumption by drawing on a range of social theory arguments and possible solutions. The chapter concludes with an agenda for future research on this topic.


Toxicon X ◽  
2021 ◽  
pp. 100069
Author(s):  
Gerardo Martín ◽  
Carlos Yáñez-Arenas ◽  
Rodrigo Rangel-Camacho ◽  
Kris A. Murray ◽  
Eyal Goldstein ◽  
...  

Eos ◽  
1989 ◽  
Vol 70 (19) ◽  
pp. 580
Author(s):  
Susan M. Bush

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