Among the plant nutrients, potassium (K) is one of the vital elements required for plant growth and physiology. Potassium is not only a constituent of the plant structure but it also has a regulatory function in several biochemical processes related to protein synthesis, carbohydrate metabolism, and enzyme activation. Several physiological processes depend on K, such as stomatal regulation and photosynthesis. In recent decades, K was found to provide abiotic stress tolerance. Under salt stress, K helps to maintain ion homeostasis and to regulate the osmotic balance. Under drought stress conditions, K regulates stomatal opening and helps plants adapt to water deficits. Many reports support the notion that K enhances antioxidant defense in plants and therefore protects them from oxidative stress under various environmental adversities. In addition, this element provides some cellular signaling alone or in association with other signaling molecules and phytohormones. Although considerable progress has been made in understanding K-induced abiotic stress tolerance in plants, the exact molecular mechanisms of these protections are still under investigation. In this review, we summarized the recent literature on the biological functions of K, its uptake, its translocation, and its role in plant abiotic stress tolerance.

Potassium: A Vital Regulator of Plant Responses and Tolerance to Abiotic Stresses

Although humic acid has been demonstrated to improve the quality of some soil types, the long-term effects of humic acid on soil under continuous cropping peanut are not fully understood. This study aimed to investigate the continuous effects of humic acid on the physicochemical properties, microbial diversity, and enzyme activities of soil under continuous cropping peanut. In this study, a three-year consecutive experiment of cropping peanut was conducted in the North China Plain. In addition to the equal nitrogen, phosphorus, and potassium inputs, humic acid treatment was applied with inorganic fertilizers. Compared with control experiments, humic acid increased the yield and quality of continuous cropping peanut. To elucidate the mechanism of humic acid affecting the soil quality, various soil quality indicators were evaluated and compared in this study. It was found that humic acid increased soil nutrient contents, including the total soil nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus, available potassium, and organic matter contents, which exhibited the maximum effect in the third year. Meanwhile, the urease, sucrase, and phosphatase activities in the soil significantly increased after treated with humic acid, of which the maturity period increased most significantly. The same results were observed for three consecutive years. Microbial diversity varied considerably according to the high throughput sequencing analysis. Specifically, the number of bacteria decreased while that of fungi increased after humic acid treatment. The abundance of Firmicutes in bacteria, Basidiomycota, and Mortierellomycota in fungi all increased, which have been reported as being beneficial to plant growth. In contrast, the abundance of Ascomycota in fungi was reduced, and most of the related genera identified are pathogenic to plants. In conclusion, humic acid improved the yield and quality of continuous cropping peanut because of improved physicochemical properties, enzymatic activities, and microbial diversity of soil, which is beneficial for alleviating the obstacles of continuous cropping peanut.

/pdf/humic-acid-fertilizer-improved-soil-properties-and-soil-47c0rway13.pdf

Humic Acid Fertilizer Improved Soil Properties and Soil Microbial Diversity of Continuous Cropping Peanut: A Three-Year Experiment

Plant biostimulants are substances which have the capacity to modify physiological processes in plants in a way that provides potential benefits to growth, development or stress response. Effects of biostimulant application on two tomato hybrids (Ombeline F1 and Bostina F1) submitted to reduced nitrogen, phosphorus and potassium (NPK) nutrition aiming at prevention of oxidative stress generation as well as yield and fruit quality loss were investigated in this study. According to obtained results, foliar applied Viva® biostimulant decreased superoxide dismutase (SOD, EC 1.15.1.1) and peroxidase (POD, EC 1.11.1.7) activity in tomato leaves even when recommended NPK nutrition was reduced at 40%. Fruit quality parameters (total soluble solids, total acidity, ascorbic acid and lycopene content) and yield were also maintained in reduced macronutrient fertilization when biostimulant was added. Combination of biostimulant with reduced NPK fertilizer enabled stability of cell homeostasis in tomato plants ...

https://tandfonline.com/doi/pdf/10.1080/17429145.2017.1319503

Biostimulant prevents yield loss and reduces oxidative damage in tomato plants grown on reduced NPK nutrition

Salinity and nutrient-depleted soil are major constraints to crop production, especially for vegetable crops. The effects of salinity and nutrient deficiency on spinach (Spinacia oleracea L.) were evaluated in sand cultures under greenhouse conditions. Plants were watered every day with Hoagland nutrition solution, deprived of nitrogen (N), phosphorous (P), or potassium (K) for nutrient deficiency, either with or without 20/10 mM sodium chloride (NaCl)/ calcium chloride (CaCl2) for salinity treatment. Salinity significantly decreased shoot fresh weight (FW) and dry weight (DW), leaf relative water content (RWC), and specific leaf area (SLA) relative to controls after 4 weeks of treatment and increased chlorophyll content, maximum photochemical efficiency (Fv/Fm), and photochemical yield [Y(II)]. Nitrogen deficiency greatly reduced shoot FW and DW, SLA, and chlorophyll content, regardless of salt treatment. Y(II) and Fv/Fm were reduced by N deficiency and salinity treatment. Phosphorous and K deficiencies, similarly, decreased shoot FW and DW irrespective of salinity treatment and increased chlorophyll content without salt stress. Phosphorous deficiency increased Y(II) under control and Fv/Fm under both control and salt treatment. Salinity and nutrient deficiency also affected the nutritional value of spinach. Salt stress increased carotenoid and flavonoid contents, and reducing power in full-strength Hoagland solution, and decreased leaf ferrous ion chelating ability (FICA). Nutrient deficiency increased reducing power regardless of salinity treatment. Nitrogen deficiency increased anthocyanin and total phenolic contents, decreased carotenoids and flavonoids regardless of salinity treatment, and increased antioxidant capacity under no-salt conditions. Phosphorous deficiency increased carotenoid and flavonoid contents under no-salt condition and enhanced total phenolic content and reduced FICA and amino acid content under salt stress. Potassium deficiency increased total phenolic, carotenoid, and flavonoid contents and antioxidant capacity under non-salt condition, but decreased FICA regardless of salinity treatment. These results suggest that spinach nutritional value could be improved with only moderately or slightly reduced yield through cultural practices that impose either low fertilizer levels or slight salt stress. High-salinity conditions in agricultural soil and irrigation water is one of the most serious challenges faced by agricultural crops in the world. It is estimated that salt-affected soils impact nearly 10% of the land surface and 50% of irrigated land in the world (Ruan et al., 2010). The response of plants to salinity is complex and involves changes in morphology, physiology, and metabolism. Salinity effects on plants include cellular water deficit, ion toxicity, nutrient deficiencies, and oxidative stress, leading to growth inhibition, molecular damage, and even plant death (Orcutt and Nilsen, 2000). The global annual losses in agricultural production from salt-affected land are in excess of $12 billion and rising (Flowers et al., 2010; Qadir et al., 2008). Another important limiting factor for crop production is soil nutrient deficiency. Nitrogen is considered the most common deficient nutrient, followed by P and K (Halvin et al., 2005). Nitrogen is a major constituent of proteins, nucleotides, chlorophyll, and many other metabolites and cellular components (Lawlor, 2002), and thus N deficiency affects enzyme activities and metabolite content, hastens senescence, causes nucleic acids and proteins to break down, and therefore inhibits plant growth (Crafts-Brandner et al., 1998; Lemâıtre et al., 2008; Wingler et al., 2006). Phosphorus is a macronutrient of crucial importance in signaling, photosynthesis, and other metabolism (Marschner, 1995). Potassium is an essential nutrient that affects most of the biochemical and physiological processes that influence plant growth and metabolism (Wang et al., 2013). Spinach is an important leafy green vegetable that contains large quantities of bioactive compounds and nutrients that are not common to most other vegetables, such as r-coumaric acid derivatives that exhibit strong antioxidant activity and glucuronic acid derivatives of flavonoids (Bergman et al., 2001; Edenharder et al., 2001; Pandjaitan et al., 2005). It was identified as a moderately salt-sensitive vegetable (Shannon and Grieve, 1999). Salt stress reduced spinach germination, root elongation, seedling growth, chlorophyll content and photosynthesis, and increased membrane permeability (Delfine et al., 1998; Downton et al., 1985; Kaya et al., 2002; Robinson et al., 1983). Langdale et al. (1971) reported that the tolerance threshold for spinach is 2.0 dS m, but irrigation with saline water of 4.0 dS m on sandy soils did not result in yield reduction (Pasternak and De Malach, 1994). Studies in solution cultures have shown that no significant growth reduction occurs up to 8 dS m (Osawa, 1963). There is limited information Received for publication 17 Aug. 2015. Accepted for publication 20 Oct. 2015. This research was supported by a grant from the California Department of Food and Agriculture Specialty Crop Block Grant Program (SCB13047). The technical assistance of Phi Diep and critical review by James McCreight and Renee Eriksen are greatly appreciated. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer. Corresponding author. E-mail: chenping.xu@ars.usda.gov. 12 J. AMER. SOC. HORT. SCI. 141(1):12–21. 2016. about the effects of micronutrient deficiency on spinach growth and physiology. With regard to nutritional quality, previous studies indicated that mild environmental stress or low fertilization could be exploited to enhance nutritional values of vegetable crops. Low N fertilization (Galieni et al., 2015; Stagnari et al., 2015) or environmental stresses, such as salt, heat, chilling, and high light intensity (Oh et al., 2009; P erezL opez et al., 2013), enhanced phenolic content and antioxidant capacity of lettuce (Lactuca sativa L.). Similarly, fruit nutritional value of tomato (Solanum lycopersicum L.) could be improved by low N supply (B enard et al., 2009) or salt stress (Borghesi et al., 2011). However, literature on spinach nutritional values affected by abiotic stresses is very scarce. The current study aims to assess the effects of salinity and single nutrient (N, P, or K) deficiency on spinach growth, physiology, and nutritional value. Materials and Methods PLANT MATERIALS AND TREATMENTS. Two trials, each with four replications, were conducted from 3 Feb. to 27 Mar. 2015 and 24 Feb. to 17 Apr. 2015, in a greenhouse located in Salinas, CA (lat. 36 40#40$N, long. 121 39#20$W). The average temperature ranged from 12 to 31 C and relative humidity ranged from 30% to 80%. The greenhouse was supplemented with light of a 12-h photoperiod (Sun System 3; Sunlight Supply, Vancouver, WA). The spinach cultivar Crocodile was used in this experiment because the preliminary study indicated that it has middle salt tolerance. For each trial, 2 weeks after seeded in rock wool cells (Grodan Group, Roermond, Netherlands), uniform spinach seedlings were transplanted into plastic pots (2.3 L) filled with sand. Plants were thinned to one plant per pot and watered every day with fullstrength Hoagland nutrition solution [electrical conductivity (EC) = 2.5 dS m] (Hoagland and Arnon, 1950). For each trial, salinity and nutrient treatments were applied 10 d after transplanting. Salinity stress was induced by adding 10/5 mM NaCl/ CaCl2 into full-strength Hoagland nutrition solution (EC = 4.6 dS m) for 2 d, and then by adding 20/10mM NaCl/CaCl2 (final EC = 6.5 dS m). To induce mild salt stress, 20/10 mM NaCl/CaCl2 was used since preliminary studies indicated that adding 40/20 mM NaCl/CaCl2 into full-strength Hoagland nutrition solution (EC = 10.2 dS m) for 4 weeks caused 50% reduction in shoot FW. Exposure of plants to increasing salt concentration allows gradual acclimation of plants to salinity conditions to avoid sudden death of plants at high salt concentration. For N, P, or K deficiency, the sources of N, P, and K in Hoagland’s solution were replaced with alternative chemicals. The N sources, calcium nitrate (5 mM) and potassium nitrate (5 mM), were replaced with CaCl2 (5 mM) and potassium sulfate (2.5 mM), respectively. The P source, potassium dihydrogen orthophosphate (1 mM), was replaced by potassium sulfate (0.5 mM). The K sources, potassium dihydrogen orthophosphate (1 mM) and potassium nitrate (5 mM), were replaced with sodium dihydrogen phosphate (1 mM) and sodium nitrate (5 mM), respectively. The plants were watered every day for 4 weeks with excess amount of respective solutions to keep the N, P, K, and salt contents in sand relatively consistent. GROWTH AND PHYSIOLOGY MEASUREMENTS. For each trial, 4 weeks after starting the treatment, leaf Fv/Fm and Y(II) were measured with a fluorometer (MINI-PAM-II; Heinz Walz, Effeltrich, Germany) on the first and third leaves from bottom of each plant. Leaf Fv/Fm was measured after leaves were adapted in darkness for 30 min. Leaf discs were collected using a cork borer from the four largest leaves of each plant to measure RWC, SLA, chlorophyll content, and nutritional values. Specific leaf area was calculated Fig. 1. Effect of salinity and nutrient deficiency on spinach shoot (A) fresh weight and (B) dry weight 4 weeks after treatment. The values are means of eight replicates ±SE. Different letters on top of bars indicate significant difference at P # 0.05 according to Student’s t test. J. AMER. SOC. HORT. SCI. 141(1):12–21. 2016. 13 as SLA = area/DW, where DW is leaf dry weight after drying at 65 C for 3 d (Evans, 1972). Leaf RWCwas calculated as RW

/pdf/responses-of-spinach-to-salinity-and-nutrient-deficiency-in-436blfl0jf.pdf

Responses of Spinach to Salinity and Nutrient Deficiency in Growth, Physiology, and Nutritional Value

With increasingly frequent extreme weather events, lodging has become an important limiting factor for crop yield and quality and for mechanical harvesting. Lodging resistance is a precondition for “super high yield” crops, and the question of how to achieve lodging resistance to guarantee high yield is an urgent scientific problem. Here, we summarize the anatomical results of lodging resistance stems and find that the lodging resistance of stems is closely related to stem components. Therefore, we focus on the roles of lignin, cellulose and hemicellulose, which provide stem rigidity and strength, in crop lodging resistance. By combing the synthetic regulatory molecular network of lignin, cellulose and hemicellulose, we find that only some of the genes involved in the biosynthesis and regulation of lignin, cellulose, and hemicellulose have been shown to significantly affect lodging resistance. However, many relevant genes remain to be studied in sufficient detail to determine whether they can be applied in breeding for lodging resistance. This work provides valuable information for future studies of lodging resistance.

/pdf/crop-lodging-and-the-roles-of-lignin-cellulose-and-hy5sxtx5.pdf

Crop Lodging and The Roles of Lignin, Cellulose, and Hemicellulose in Lodging Resistance

Humic acid (HA), not only promote the growth of crop roots, they can be combined with nitrogen (N) to increase fertilizer use efficiency and yield. However, the effects of HA urea fertilizer (HA-N) on root growth and yield of sweet potato has not been widely investigated. Xushu 28 was used as the experimental crop to investigate the effects of HA-N on root morphology, active oxygen metabolism and yield under field conditions. Results showed that nitrogen application alone was not beneficial for root growth and storage root formation during the early growth stage. HA-N significantly increased the dry weight of the root system, promoted differentiation from adventitious root to storage root, and increased the overall root activity, total root length, root diameter, root surface area, as well as root volume. HA-N thus increased the activity of superoxide dismutase (SOD), peroxidase (POD), and Catalase (CAT) as well as increasing the soluble protein content of roots and decreasing the malondialdehyde (MDA) content. HA-N significantly increased both the number of storage roots per plant increased by 14.01%, and the average fresh weight per storage root increased by 13.7%, while the yield was also obviously increased by 29.56%. In this study, HA-N increased yield through a synergistic increase of biological yield and harvest index.

/pdf/responses-of-root-physiological-characteristics-and-yield-of-4v6fbs3v13.pdf

Responses of root physiological characteristics and yield of sweet potato to humic acid urea fertilizer.

/pdf/growth-and-physiological-response-to-nitrogen-deficiency-and-2ett8faka9.pdf

Growth and Physiological Response to Nitrogen Deficiency and Re-supply in Leaf-vegetable Sweetpotato (Ipomoea batatas Lam)

The invention discloses a three-segment healthy purple micro yam breeding method, and belongs to the field of yam seedling breeding methods. The three-segment rapid yam seedling breeding method is utilized in the seedling growing method, healthy micro yam seedlings without soil-borne diseases and yam-borne diseases are produced from purple yam seedlings without yam tubers and are non-contact with soil, factorial production is implemented, a large amount of healthy micro yam seedlings are bred intensively, breeding efficiency of purple yam seedlings can be improved, and production cost can be reduced. Yield of purple yams is increased by 15 to 20% per mu, original fine species and yield of the purple yams are recovered, and planting benefits of soil per unit area is increased.

Three-segment healthy purple micro yam breeding method

Compound fertilizer special for sweet potatoes and preparation method thereof

The invention discloses an annual double cropping efficient planting pattern of triticale and purple yam in a Huang-Huai region, and belongs to the filed of crop planting The plating pattern comprises the following steps: selection of new varieties of the triticale and the purple yam, timely sowing, field management, disease and pest control, harvest time and manner Water, nutrients and light and heat resources in the Huang-Huai region are explored, the triticale is harvested in summer, and then the purple yam is harvested after crop rotation in autumn, so that the land cropping index is improved, the agricultural income per unit area of land is increased, and the income is increased by 2500-3000 yuan per acre usually; meanwhile, the continuous cropping obstacles of yam in the region are overcome The economic income of special economic crops and special grain crops planted by rotation is obviously higher than that of pure grain crops or pure economic crops, and the economic benefits are very substantial

Annual double cropping efficient planting pattern of triticale and purple yam in Huang-Huai region

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Wei Meng

Author Tools

Chat about Author