Potassium Deficiency In Cotton Research Articles

Potassium Deficiency in Cotton: Causes, Symptoms, and Considerations

The purpose of this publication is to inform cotton producers, Extension agents, crop advisors, and consultants about the role, deficiency, and management of potassium in cotton production. Written by Kulpreet Singh, Hardeep Singh, Peter Omara, Nkem J. Nwosu, Jennifer Bearden, Ravinder Singh, and Lakesh K. Sharma, and published by the UF/IFAS Agronomy Department, January 2024.

Genome-wide identification of CBL family and expression analysis of CBLs in response to potassium deficiency in cotton.

Calcineurin B-like (CBL) proteins, as calcium sensors, play pivotal roles in plant responses to diverse abiotic stresses and in growth and development through interaction with CBL-interacting protein kinases (CIPKs). However, knowledge about functions and evolution of CBLs in Gossypium plants is scarce. Here, we conducted a genome-wide survey and identified 13, 13 and 22 CBL genes in the progenitor diploid Gossypium arboreum and Gossypium raimondii, and the cultivated allotetraploid Gossypium hirsutum, respectively. Analysis of physical properties, chromosomal locations, conserved domains and phylogeny indicated rather conserved nature of CBLs among the three Gossypium species. Moreover, these CBLs have closer genetic evolutionary relationship with the CBLs from cocoa than with those from other plants. Most CBL genes underwent evolution under purifying selection in the three Gossypium plants. Additionally, nearly all G. hirsutum CBL (GhCBL) genes were expressed in the root, stem, leaf, flower and fiber. Many GhCBLs were preferentially expressed in the flower while several GhCBLs were mainly expressed in roots. Expression patterns of GhCBL genes in response to potassium deficiency were also studied. The expression of most GhCBLs were moderately induced in roots after treatments with low-potassium stress. Yeast two-hybrid experiments indicated that GhCBL1-2, GhCBL1-3, GhCBL4-4, GhCBL8, GhCBL9 and GhCBL10-3 interacted with GhCIPK23, respectively. Our results provided a comprehensive view of the CBLs and valuable information for researchers to further investigate the roles and functional mechanisms of the CBLs in Gossypium.

Genotypic variations in photosynthetic and physiological adjustment to potassium deficiency in cotton (Gossypium hirsutum)

A hydroponic culture experiment was conducted to determine genotypic variation in photosynthetic rate and the associated physiological changes in response to potassium (K) deficiency in cotton (Gossypium hirsutum L.) seedlings with contrasting two cotton cultivars in K efficiency. The K-efficient Liaomian18 produced 66.7% more biomass than the K-inefficient NuCOTN99B under K deficiency, despite their similar biomass under K sufficiency. Compared with NuCOTN99B, Liaomian18 showed 19.4% higher net photosynthetic rate (Pn, per unit leaf area) under K deficient solutions and this was associated with higher photochemical efficiency and faster export of soluble sugars from the phloem. The lower net Pn of NuCOTN99B was attributed to higher capacity for nitrate assimilation and lower export of soluble sugars. Furthermore, NuCOTN99B showed 38.4% greater ETR/Pn than Liaomian18 under K deficiency, indicating that more electrons were driven to other sinks. Higher superoxide dismutase (SOD) and lower catalase (CAT) and ascorbate peroxidase (APX) activities resulted in higher levels of reactive oxygen species (ROS; e.g. O2−and H2O2) in NuCOTN99B relative to Liaomian18. Thus, the K inefficiency of NuCOTN99B, indicated by lower biomass and net Pn under K deficiency, was associated with excessively high nitrogen assimilation, lower export of carbon assimilates, and greater ROS accumulation in the leaf.

Relationships between Insufficient Potassium and Crop Maturity in Cotton

Potassium deficiency in cotton (Gossypium hirsutum L.) depresses yield by decreasing late season growth and is reportedly more harmful to early maturing cotton genotypes. Research objectives were to determine if the accelerated maturity caused by K deficiency was partially caused by earlier flowering and to further evaluate whether early maturity cotton genotypes are more susceptible to low K levels. Field studies were conducted from 1995 to 1997 utilizing two okra‐normal leaf‐type near isoline pairs and two K fertilization rates (0 and 112 kg K ha−1). Okra leaf‐type genotypes are earlier in maturity than their normal leaf‐type counterparts. White bloom counts, dry matter partitioning, light interception, lint yield, yield components, and fiber quality data were collected. Genotypes responded similarly to K rates for all of the parameters evaluated. Early season flowering rates briefly increased 11% when plants were grown without supplemental K. Late‐season leaf area index (LAI) was 23% lower without supplemental K compared with plants fertilized with 112 kg K ha−1 in 2 of the 3 yr. The increased LAI of the K‐fertilized plants allowed them to intercept 6% more of the late season sunlight than the 0 kg K ha−1 treatment. Potassium fertilization increased yield 9% in 2 out of 3 yr, but low K had only minor effects on fiber quality. Early maturing okra‐leaf cotton genotypes are not more susceptible to low K rates because of their early maturity. The low K effect on crop maturity is due to a premature termination of reproductive growth and a brief enhancement of the early season flowering rate.

Physiological changes associated with potassium deficiency in cotton

Potassium (K) fertility recommendations based on cotton petiole diagnostic analysis results have been inconsistent in the past, partly because the lowest acceptable petiole K concentration is unknown. Therefore, cotton was grown in sand filled 8‐L pots under two K treatments in a growth chamber at the Altheimer Laboratory in Fayetteville, AR to determine the petiole K concentration that will impact leaf physiology. Chamber‐grown plants were watered every second day with nutrient solution and with deionized water on alternate days. At 14 days after planting two treatments were established consisting of (1) continued complete nutrient solution, and (2) nutrient solution containing no K. Measurements were taken 13, 19, and 26 days after treatment establishment (DATE). Organ K concentrations, leaf chlorophyll, photosynthesis, adenosine triphosphate (ATP), and nonstructural carbohydrate concentrations were monitored as plant K deficiencies developed. All organ K concentrations were much lower in the no‐K treatment on each analysis date. Visual K deficiencies were first observed at 19 DATE along with reductions reductions in leaf chlorophyll concentration. Leaf photosynthesis was greatly reduced in the no‐K treatment beginning at 19 DATE. However, leaf ATP and nonstructural carbohydrate concentrations were higher at 19 and 26 DATE in the no‐K treatment, which may have been the result of reduced utilization and translocation of these metabolites. Our studies show that reductions in leaf physiological processes and plant growth did not occur until the petiole K concentration fell below 0.88% on a dry weight basis. Therefore, reductions in lint yield and quality should not develop until this critical petiole level is attained.

Development of a protocol to study the effects of potassium deficiency in cotton under controlled environmental conditions

Cotton (Gossypium hirsutum L.) was grown in two separate experiments in a growth chamber to develop an experimental protocol for studying the effects of potassium (K) deficiency in cotton under controlled environmental conditions. Hydroponic culture techniques were implemented in the first study and sand culture techniques in the second study. Potassium was regulated in these studies by substituting all K salts with the corresponding Na salts. Leaf areas, tissue dry weights and tissue K and sodium (Na) concentrations were recorded. These studies indicated additional Na in the nutrient solutions containing less K resulted in increased tissue Na concentrations, which may have substituted for K in the plant and delayed the development of a K deficiency. Therefore, a modified solution was developed and utilized for studying the effects of K deficiency on cotton growth under controlled environmental conditions.