Potassium (K+) in Plants

As an invited guest editor of the Journal of Plant Physiology, Ingo Dreyer organized a special issue on ‘Potassium (K+) effect in plants’. This compendium provides a stock-check of the current knowledge in the field, and will provide readers with a first glimpse into a holistic view on ‘Potassium (K+) in Plants’.

Potassium (K+) is the most abundant inorganic cation in plant cells. Many research publications on K+ start in a similar way. Indeed, K+ is vital for plant growth. Together with nitrogen (N) and phosphorous (P), K+ belongs to the top three elements, the availability of which strongly determines crop yield. Undeniably, the application of mineral NPK-fertilizers was an essential cornerstone of the green revolution in the last century.

Limited resources are now forcing us to investigate how the plants’ K+ demand can be satisfied with the minimum of fertilizer application. The indispensable ground for providing answers to this complex question is the understanding of the exact roles of K+ in plants. This special issue provides contemporary views from different perspectives on ‘Potassium in Plants’. It spans the whole range, from agricultural aspects of potassium nutrition (Zörb et al., 2014), through the manifold physiological roles that K+ plays (Anschütz et al., 2014; Demidchik, 2014), to the molecular aspects of potassium uptake from the soil (Nieves-Cordones et al., 2014) and its distribution throughout the plant (Ahmad and Maathuis, 2014; Wigoda et al., 2014). It addresses the molecular bases of the subcellular compartmentalization of K+ (Hamamoto and Uozumi, 2014), as well as the problematic relationship of K+ with its ‘evil’ twin, the sodium ion (Na+), which together with Cl-, is the main damaging effect of yield-reducing salt stress (Benito et al., 2014; Pottosin and Dobrovinskaya, 2014).

The molecular knowledge of K+ transport in plants has mainly been obtained from only a few model species. Only recently have the number of investigated species started to increase significantly. Véry et al. (2014) summarize exemplarily the available information for three K+ transporter classes and discuss the question as to how much this available information from model species can be transferred to other plant species.

The involvement of K+ (and, of course, other nutrients) in the diverse range of physiological processes is highly dynamic and is so complex that an intuitive understanding is often difficult or even misleading. However, modern approaches can offer a way out of this dilemma. To get a ‘feeling’ for the system’s behavior, we need to feed computer programs with all the information gathered in ‘wet-lab’ experiments and run computational simulations (so called ‘dry-lab’ experiments). The computer allows quick changes of parameters, thus enabling the possibility of testing many hypotheses in a short time to filter those out that are worth testing in (time-consuming and much more expensive) wet-lab experiments. To ease the path into this ‘next generation experimentation’, Blatt et al. (2014) provide a hands-on tutorial to simulate exemplarily behavior of guard cells.

This compendium prepared by 34 authors, provides a stock-check of the current knowledge in the field. In addition, it will provide readers who are not familiar with the subject, a first step towards a holistic view on ‘Potassium (K+) in Plants’.

Índice

Ingo Dreyer
Potassium (K+) in Plants

Christian Zörb, Mehmet Senbayram, Edgar Peiter
Potassium in agriculture – status and perspectives

Uta Anschütz, Dirk Becker, Sergey Shabala
Going beyond nutrition: Regulation of potassium homoeostasis as a common denominator of plant adaptive responses to environment

Manuel Nieves-Cordones, Fernando Alemán, Vicente Martínez, Francisco Rubio
K+ uptake in plant roots. The systems involved, their regulation and paralle in other organisms

Vadim Demidchik
Mechanisms and physiological roles of K+ efflux from root cells

Izhar Ahmad, Frans J.M. Maathuis
Cellular and tissue distribution of potassium: Physiological relevance,mechanisms and regulation

Noa Wigoda, Menachem Moshelion, Nava Moran
Is the leaf bundle sheath a “smart flux valve” for K+ nutrition?

Begoña Benito, Rosario Haro, Anna Amtmann, Tracey Ann Cuin, Ingo Dreyer
The twins K+ and Na+ in plants

Igor Pottosin, Oxana Dobrovinskaya
Non-selective cation channels in plasma and vacuolar membranes and their contribution to K+ transport

Shin Hamamoto, Nobuyuki Uozumi
Organelle-localized potassium transport systems in plants

Anne-Aliénor Véry, Manuel Nieves-Cordones, Meriem Daly, Imran Khan, Cécile Fizames, Hervé Sentenac
Molecular biology of K+ transport across the plant cell membrane: what do we learn from comparison between plant species?

Michael R. Blatt, Yizhou Wang, Nathalie Leonhardt, Adrian Hills
Exploring emergent properties in cellular homeostasis using OnGuard to model K+ and other ion transport in guard cells