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Potassium
Biology 213
Spring 2014
Bailey, Yamuna, Robel
Potassium Overview
 Potassium is an essential plant nutrient and is required
in large amounts for proper growth and reproduction of
plants.
 Potassium is considered second only to nitrogen, when
it comes to nutrients needed by plants.
 commonly considered as the “quality nutrient.”
 It affects the plant shape, size, color, taste and other
measurements attributed to healthy produce.
How do plants use Potassium?
 Enzyme Activation: Catalyst for chemical reaction
 Stomatal activity (water use): Regulate opening and closing
of stomates, the pores through which leaves exchange CO2,
water vapor, and O2 with the atmosphere.
 Photosynthesis: Triggered by the activation of enzymatic
reactions by K
 Transport of sugars: Sugars produced in photosynthesis
must be transported to other parts of the plant for utilization
and storage. Plant’s transport system uses energy in the
form of ATP.
 Transport of water and nutrient: K transports water and
nutrients throughout the plant in the xylem.
Potassium Deficiency (Causes)
 It is soluble: so easily washed away from the soil by
rainfall and irrigation water.
 It occurs in sandy low in organic matter
 It prefers neutral soil and may not be available in acidic
soil with below pH 5
Potassium Deficiency
(Symptoms)
 Yellowing of the margin of the leaf- Chlorosis
 Necrotic (dead) spots on older leaves
 Browning and death of tips and margins.
 Leaves roll inward dying of leaf margin
 Leaves turn yellow, then brown and eventually fall off one by
one.
 Older leaves are affected first
 Slower and stunted growth
 More susceptible to drought and temperature change
 Poorly development root system
 Undersized fruits and poorly colored
Under sized fruits
Stunted growth
Chlorosis
Curling of Leaf Margin
Browning of Leaf Margin
How do plants access to
potassium?
 Plants absorb potassium
in its ionic form, K+.
 Potassium is supplied to
plants by soil minerals,
organic materials, and
fertilizer.
 the amount of potassium
supplied by soils varies.
 Three forms of potassium
exist in soils

unavailable

slowly available or fixed

readily available
Prevention of Potassium Loss
 Mineral nutrients are usually obtained
from the soil through plant roots.
Potassium deficiency occurs
frequently in plants grown on sandy
soils.
 Potassium is supplied to plants by soil
minerals, organic materials, and
fertilizer.
 Common forms of inorganic fertilizers
include potassium nitrate and
potassium sulfate.
 Other potassium-rich treatments
include compost rich in decayed
banana peels, or other organic
potassium-rich fertilizers.
Factors that may affect potassium
uptake
 Soil Moisture: Higher soil moisture usually means greater
availability of K. Increasing soil moisture increases movement of K
to plant roots and enhances availability.
 Soil Oxygen Level: Air is necessary for root respiration and K
uptake. Levels of oxygen are very low in saturated soils. K uptake
decrease as the saturation of soil increases.
 Soil Temperature: Root activity, plant functions, and physiological
processes all increase as soil temperature increases. This
increase in physiological activity leads to increased K uptake.
Optimum soil temperature for uptake is 60-80°F. Potassium uptake
is reduced at low soil temperatures.
Sources
Cain, M. L., Campbell, N. A., Jackson, R. B., Minorsky, P. V., Reece, J. B., Urry,
L. A., Wasserman, S. A. (2010) Campbell Biology. Boston:
Benjamin
Cummings.
Morgan. J. B. & Connolly E. L. (2013) Plant-Soil Interactions: Nutrient
Uptake. Nature Education Knowledge 4(8):2 Retrieved from:
http://www.nature.com/scitable/knowledge/library/plant-soil-interactions-nutrientuptake-105289112
Pettigrew, W. T. (2008) Potassium influences on yield and quality production
for maize, wheat, soybean and cotton. Physiologia Plantarum,
133(4), 670-681.
Plant responses to potassium deficiencies: a role for potassium transport
proteins. (2006) Journal of Experimental Botany, 57(2), 425–436
United States. North Carolina Department of Agriculture & Consumer
Services. (2014, May) Plant Nutrients. Retrieved from:
http://www.ncagr.gov/cyber/kidswrld/plant/nutrient.htm