Potassium Control of Plant Functions: Ecological and Agricultural Implications

Abstract

Potassium, mostly as a cation (K+), together with calcium (Ca2+) are the most abundant inorganic chemicals in plant cellular media, but they are rarely discussed. K+ is not a component of molecular or macromolecular plant structures, thus it is more difficult to link it to concrete metabolic pathways than nitrogen or phosphorus. Over the last two decades, many studies have reported on the role of K+ in several physiological functions, including controlling cellular growth and wood formation, xylem–phloem water content and movement, nutrient and metabolite transport, and stress responses. In this paper, we present an overview of contemporary findings associating K+ with various plant functions, emphasizing plant-mediated responses to environmental abiotic and biotic shifts and stresses by controlling transmembrane potentials and water, nutrient, and metabolite transport. These essential roles of K+ account for its high concentrations in the most active plant organs, such as leaves, and are consistent with the increasing number of ecological and agricultural studies that report K+ as a key element in the function and structure of terrestrial ecosystems, crop production, and global food security. We synthesized these roles from an integrated perspective, considering the metabolic and physiological functions of individual plants and their complex roles in terrestrial ecosystem functions and food security within the current context of ongoing global change. Thus, we provide a bridge between studies of K+ at the plant and ecological levels to ultimately claim that K+ should be considered at least at a level similar to N and P in terrestrial ecological studies.

Potassium fertilization improves growth, yield and seed quality of sunflower (Helianthus annuus L.) under drought stress at different growth stages

“…Better performance of sunflower in terms of yield and yield components under higher K fertilization is due to the involvement of K in main osmotic solute of plants [ 28 , 37 ]. Potassium accumulation at the cellular level results in osmotic water uptake and generation of cell turgor needed for stomatal opening and plant growth [ 38 , 39 ]. Potassium influx inside the stomatal guard cells cause water accumulation leading to their swelling and subsequent stomatal opening, allowing CO 2 and transpired water vapors to move freely in and out of plant tissues.…”

“…In case of inadequate supply of K, the stomatal activity becomes slow and water losses are high. However, adequate K supply increases plant uptake of water as well as improves its use efficiency within the plant [ 39 – 41 ].…”

The Dynamics of Mass Loss and Nutrient Release of Decomposing Fine Roots, Needle Litter and Standard Substrates in Hemiboreal Coniferous Forests

“…Litter quality, which is mainly determined by the relative content of recalcitrant organic compounds (e.g., lignin or phenols) and macronutrients, is of particular importance in controlling the mass loss and dynamics of litter nutrients during decay under similar climatic conditions (Prescott et al, 2000;Berg and McClaugherty, 2008). Several studies have shown that high initial nitrogen (N), phosphorus (P), and potassium (K) concentrations in litter regulate the early stages of decomposition by stimulating the decay of celluloses and solubles (Berg and Staaf, 1980;Berg and Matzner, 1997;Chen et al, 2002;Cusack et al, 2009;Sardans and Penuelas, 2021). However, high N inhibits the decay in the later stages by suppressing the activity of lignolytic enzymes (Carreiro et al, 2000) and shifting the decomposercommunity composition (Couteaux et al, 1995).…”

Effects of Combined Potassium and Organic Fertilizer Application on Newhall Navel Orange Nutrient Uptake, Yield, and Quality

“…K is taken up very efficiently and longdistance transport occurs in the xylem and phloem throughout the plant. K is involved in all aspects of plant growth and has many different functions [1]. By adjusting plant water requirements through influencing the transpiration process [2], K plays a key role in the transport of photosynthates, the regulation of stomatal physiological mechanisms, the synthesis of carbohydrates [3], and is directly related to the regulation of the cell osmotic potential to minimize stress responses [4].…”