Interactive Effects Of Potassium Research Articles

Interactive Effects of Potassium and Mycorrhizal Fungi on Glomalin and Biochemical Responses of Sunflower Grown in a Pb and Zn Contaminated Soil

ABSTRACT It is well documented that sole application of potassium (K) or mycorrhizal fungi can alleviate heavy metal stress in plants. As an indicator of the efficient defense in the mycorrhizal fungi-plant system, glomalin synthesis in the rhizosphere can be determined. In this study, interactive effects of mycorrhizal fungi (MY) and K on glomalin content, heavy metal uptake and mycorrhizal properties of sunflower plants were examined with three soil K levels (0, 100, and 200 mg K kg−1 using K2SO4). The three levels of mycorrhization are: i) no mycorrhizal inoculation, ii) Rhizophagus irregularis inoculation, and iii) mixed mycorrhizal inoculum application. Joint application of potassium and mycorrhiza significantly increased the percentage of root colonization and easily extractable glomalin (EEG), showing 56% root colonization in the treatment of K100 + mixed mycorrhiza and 178 µg EEG g−1 in the treatment of K200 + mixed mycorrhiza. Joint application of MY and K significantly reduced the translocation of heavy metals to the shoot of the plants. The highest total uptake of Zn by plants per pot (2.01 mg pot −1) and Pb (0.78 mg pot −1) were found in non-mycorrhizal plants. The MY and K treatments also increased the chlorophyll content and leaf area index by 57%. This study concluded that application of potassium and mycorrhizal fungi enhanced glomalin production and increased plant resistance to heavy metal stress.

Interactive effects of potassium and saline water on yield, nutrient accumulation and uptake by rice

A pot culture experiment was conducted to assess the interaction effects of salinity and potassium nutrition on rice during 2018.A pot experiment was conducted in CRD with three replications and twelve treatments consist of four levels of saline water (0, 2, 4 and 8 dS m-1) and three doses of potassium (60, 120 and 180 kg ha-1). The crop received a common dose of N @ 120 kg ha-1 (in splits) and P @ 60 kg ha-1. The crop received saline water irrigation up-to saturation point at 30, 45, 60 and 80 DAP (days after planting). The study indicated that the cumulative application of saline water @ 4 and 8 dS m-1 decreased the grain yield and straw yield, yield components, potassium content and uptake by rice whereas, sodium content and uptake increased significantly at higher level of salinity (4 and 8 dS m-1). The adverse effect of Na was reduced with application of potassium. The grain and straw yield, yield component, potassium content and uptake by rice was increased with increasing the dose of potassium. The sodium content and uptake by rice was reduced significantly with higher dose of potassium (180 kg ha-1) application. Based on the present study, split application of potassium @ 180 kg ha-1 is recommended for rice in saline soil. The K+/Na+ ratio in soil and plant can be considered as a best indicator in evaluating crop performance in saline soil.

Nitrogen and potassium requirements of tomato plants for the optimization of fruit quality and antioxidative capacity during storage

While nitrogen (N) and potassium (K) fertilizers are commonly used in tomato fields for increasing plant growth and productivity, concepts regarding the interactive effects of these elements on tomato fruit quality during storage are ambiguous. The interactive effects of potassium (0, 250 and 500 mg kg soil− 1) and nitrogen (0, 150 and 300 mg kg soil− 1) fertilizers were tested on tomato fruit size at harvest, and their quality was evaluated after 30 days of storage at 4 °C. Fruit mass, firmness, taste-related parameters, inorganic nutrients, bioactive compounds, and antioxidative capacity of the fruits were investigated after the storage period. Application of 250–500 mg K in combination with 150 mg N per kg soil improved fruit mass at harvest and reduced loss of mass during storage. By increasing the soil’s K supply, the fruits exhibited significant increases in their amount of potassium, TSS and TA contents, antioxidative capacity, concentrations of lycopene, phenolics and ascorbic acid. Nonetheless, increasing the soil’s K concentration reduced Ca concentration and firmness of the fruits. By increasing the N concentration in the soil, a trend of decline was observed in the fruits’ TSS, soluble phenolics, lycopene and ascorbic acid contents. However, higher amounts of N and TA contents were detected in fruits treated with 300 mg N kg soil− 1. N treatments did not affect the antioxidative capacity of the fruits. Accordingly, application of 250 mg K + 150 mg N kg soil− 1 was suggested as the optimum treatment that could yield tomato fruits with high quality and that would also have improved storage capability.

Interactive Effects of Potassium and Phosphorus on Phenology and Grain Yield of Sunflower in Northwest Pakistan

Potassium (K) and phosphorus (P) applications improve growth, increase yield and yield components of sunflower ( Helianthus annuus L.) on K and P deficient soils in Northwest Pakistan. A field experiment was conducted using sunflower cv. Hysun-33 at the New Developmental Research Farm of KPK Agricultural University, Peshawar, Pakistan, during summer 2006. The experimental design was a randomized complete block in split plot arrangements, with six levels of K (0, 25, 50, 75, 100, and 125 kg K ha −1) as main plots and four levels of P (0, 45, 90, and 135 kg P ha −1) as sub-plots with three replications. Sunflower yield and yield components responded positively to K and P fertilization but the magnitude of response varied with the levels of K and P. Days to flowering and maturity, grains per head, 1000-grain weight, shelling percentage, and grain yield increased tremendously in the K and P-fertilized plots as compared to the control with no K and P applied. The combined application of 100 kg K and 45 kg P ha −1 significantly increased yield components, grain yield, harvest index, and shelling percentage of sunflower, suggesting that 100 kg K ha −1 in combination with 45 kg P ha −1 could maximize productivity of sunflower planted after wheat on the K and P deficient soils in the study area.

Interactive effects of potassium and nitrogen on root system architecture and expression of transporters

Interactive effects of potassium and nitrogen on root system architecture and expression of transporters

Interactive effects of potassium and sodium on root growth and expression of K/Na transporter genes in rice

Sufficient supply of potassium (K) can alleviate the adverse effects of excess sodium (Na) on plant growth. However, it remains unclear if such a beneficial function is related to regulation of root growth and/or expression of K/Na transporters. Herein we report the responses of a rice cultivar, which was pretreated with normal nutrient solution for 1 month, to three levels of Na (0, 25, and 100 mM) without or with supply of K for 9 days. High Na (100 mM) significantly decreased plant growth, root activity, and total K uptake, and increased biomass ratio of roots to shoots. Short-term removal of K supply (9 days) did not affect root morphology and biomass ratio of roots to shoots, but decreased root activity of seedlings grown in high Na solution. K deficiency increased uptake of Na and transport of K from roots to shoots. Moreover, expression of OsHAK1, a putative K transporter gene, was upregulated by low Na (25 mM) and downregulated by high Na (100 mM) in roots. In leaves, its expression was suppressed by the Na treatments when K supply was maintained. Expression of OsHKT2;1, which encodes a protein that acts mainly as a Na transporter, was downregulated by high Na, but was enhanced by K deficiency both in roots and leaves. Expression of five other putative K/Na transporter or Na+/H+ genes, OsHKT1;1, OsHKT1;2, OsHKT2;3, OsNHX1, and OsSOS1, was not affected by the treatments. The results suggest that OsHAK1 and OsHKT2;1 were involved in the interactive effects of K and Na on their uptake and distribution in rice.

Interactive Effects of Potassium and Calcium on K/Ca Ratio and Its Consequences on Apple Fruit Quality in Calcareous Soils of Iran#

This research was carried out during the 2000–2001 growing season in a low-density orchard, on a calcareous soil (Fine loamy, mixed, mesic Typic Calcixerept) in northwest Iran, using 25-year old “Golden Delicious” (Malus domestica Borkh.) apple trees on M.9 rootstock. The interactive effects of potassium (K) and calcium (Ca) on K/Ca ratio and its consequences on apple fruit quality were studied. Treatments included: T 1 = control [nitrogen (N), phosphorus (P), and manure]; T 2 = T 1 + micronutrients (deep placement) based on soil test recommendations; T 3 = T 2 + (KCl)1 based on soil test recommendations; T 4 = T 3 + spray of CaCl2 at four times; T 5 = same as T 4 but sprayed at eight times; T 6 = T 2 + (KCl)2 (50% above soil test); T 7 = T 6 + spray of CaCl2 at four times; T 8 = same as T 7 but sprayed at eight times; T 9 = same as T 8 but with an equal amount of K from K2SO4 source. Leaf samples were collected in early July and fruit samples collected in early October and were analyzed for N, K, and Ca. Thirty fruit samples were randomly selected and stored at 1°C for 45 or 90 days prior to determination of their storage life. There was a range in K and Ca level in the leaves, although both K and Ca concentrations exceeded their critical threshold values. The concentration of K in the fruit was high, but Ca was low. There was a positive correlation between leaf K and fruit K and between fruit K and total soluble solids concentration (SSC); between fruit Ca and apple fruit firmness; but negative correlations existed between K/Ca ratio and apple fruit firmness at harvest. Apple fruit SSC was increased by K-fertilization and storage period. Fruit firmness in harvest samples was the highest in plots which had received Ca sprays. Apple firmness at harvest was generally low for all treatments and reduced by duration of storage and differences among treatments were not large after 90-day storage. Variation of K/Ca ratio in the apple leaves was slight (0.9–1.4), but a wide range was observed for fruit (19–46). The highest ratio (46) occurred for T 6 and the lowest ratio (19) for T 8 and T 9. An inverse relationship between K/Ca ratios and fruit firmness indicated that on calcareous soils, at least 8-foliar applications of CaCl2 solution were necessary for “Golden Delicious” apple. #Contribution no. 2191, PARC-Summerland.