Exogenous Spermidine Affected Leaf Characteristics and Growth of Common Bean Under Water Deficit Conditions

In order to investigate the effects of exogenous spermidine on water limitation-induced damage on common bean (Phaseolus vulgaris L.) genotypes, a field experiment was conducted over two growth seasons. The experiment was arranged as a split-split plot design and three replications. Treatments were three water stress levels (non-stress, moderate and severe stress), three bean genotypes (Akhtar, Pak and COS12) and two spermidine levels (control and foliar application). The results showed that water stress reduced markedly leaf relative water content, SPAD values, specific leaf area, leaf area index, plant height, relative growth rate, shoot dry weight and grain yield; however, increased leaf density, leaf relative electrolyte leakage, stomatal density, leaf angle and leaf temperature of bean genotypes. Spermidine application increased relative water content, SPAD values, leaf area, leaf area index, shoot dry weight and grain yield. Overall, exogenous spermidine usage as a free radical scavenger counteracted deleterious water deficit effects.     

Cu induced changes of ultrastructure and bioaccumulation in the leaf of Moso bamboo (Phyllostachys pubescens)

The effects of Copper (Cu) on growth of Moso bamboo (Phyllostachys heterocycla (Carr.) Mitford cv. pubescens) were investigated. The dry weight of Moso bamboo was inhibited and significant differences were evident under Cu stress as compared to the control (CK). Solution culture experiments indicated that Moso bamboo had a strong ability to accumulate Cu in shoots. Copper accumulation in the stem was stronger than the leaves; the stem/root ratio could reach 0.20 under Cu stress. The changes in cell walls, stomata, vacuoles, and starch grains content were observed via scanning electron microscopy and transmission electron microscopy. The ultrastructural analysis revealed that the excessive Cu concentrations caused deformities in the chloroplasts and transformation and even disappearance of endoplasmic reticulum. Moso bamboo as an experimental material serves as a new tool for remediation of heavy metal contaminated soils due to its metal tolerance and excessive biomass production.     

Nitrous oxide emission from an irrigated cotton field under semiarid subtropical conditions

In a 1-year study, quantification of nitrous oxide (N₂O) emission was made from a flood-irrigated cotton field fertilized with urea at 100kg N ha⁻¹ a⁻¹. Measurements were made during the cotton-growing season (May–November) and the fallow period (December–April). Of the total 95 sampling dates, 77 showed positive N₂O fluxes (range, 0.1 to 33.3g N ha⁻¹ d⁻¹), whereas negative fluxes (i.e., N₂O sink activity) were recorded on 18 occasions (range, −0.1 to −2.2g N ha⁻¹ d⁻¹). Nitrous oxide sink activity was more frequently observed during the growing season (15 out of 57 sampling dates) as compared to the fallow period (3 out of 38 sampling dates). During the growing season, contribution of N₂O to the denitrification gaseous N products was much less (average, 4%) as compared to that during the fallow period (average, 21%). Nitrous oxide emission integrated over the 6-month growing period amounted 324g N ha⁻¹, whereas the corresponding figure for the 6-month fallow period was 648g N ha⁻¹. Subtracting the N₂O sink activity (30.3g N ha⁻¹ and 3.8g N ha⁻¹ during the growing season and fallow period, respectively), the net N₂O emission amounted 938g N ha⁻¹ a⁻¹. Results suggested that high soil moisture and temperature prevailing under flood-irrigated cotton in the Central Punjab region of Pakistan though favor high denitrification rates, but are also conducive to N₂O reduction thus leading to relatively low N₂O emission.     

Genetic variation in drought resilience-related traits among wheat multiple synthetic derivative lines: insights for climate resilience breeding

Twenty-four wheat lines, developed by Aegilops tauschii Coss. introgressions and previously selected for heat or salinity stress tolerance, were evaluated under a drought-rewatering-drought cycle for two years. The objective was to select breeding lines that are resilient to more than one abiotic stress. The experiment was designed in alpha lattice with three replications. Drought was imposed by withholding water during flowering. The results revealed considerable genetic variability in physio-agronomic traits, reflecting the variation in the introgressed segments. High heritability estimates (above 47%) were recorded for most traits, including days to 50% heading, plant height, and thousand-grain weight, indicating the genetic control of these traits which may be useful for cultivar development. The trait-trait correlations within and between water regimes highlighted a strong association among the genetic factors controlling these traits. Some lines exhibited superior performance in terms of stress tolerance index and mean productivity compared with their backcross parent and elite cultivars commonly grown in hot and dry areas. Graphical genotyping revealed unique introgressed segments on chromosomes 4B, 6B, 2D, and 3D in some drought-resilient lines which may be linked to drought resilience. Therefore, we recommend these lines for further breeding to develop climate-resilient wheat varieties.     

Toxicity of formic acid to red imported fire ants, Solenopsis invicta Buren

BACKGROUND: Ants often compete with other ants for resources. Although formic acid is a common defensive chemical of formicine ants, it does not occur in any other subfamilies in Formicidae. No information on toxicity of formic acid to red imported fire ants, Solenopsis invicta, is available. This study examined its contact and fumigation toxicity to S. invicta in the laboratory. RESULTS: In a contact toxicity bioassay, 24 h LD₅₀ values of formic acid for workers ranged from 124.54 to 197.71 µg ant⁻¹. Female alates and queens were much less sensitive to formic acid than workers. At a concentration of 271.72 µg ant⁻¹, which killed 81.09 ± 16.04% of workers, the 24 h mortality was up to 39.64% for female alates and 38.89% for queens. In fumigation bioassays, 24 h LC₅₀ values ranged from 0.26 to 0.50 µg mL⁻¹ for workers, 0.32 µg mL⁻¹ for male alates and 0.70 µg mL⁻¹ for female alates. Complete mortality (100%) in queens occurred 24 h after they had been exposed to 1.57 µg mL⁻¹ of formic acid. At a concentration of 2.09 µg mL⁻¹, KT₅₀ values ranged from 23.03 to 43.85 min for workers, from 37.84 to 58.37 min for male alates, from 86.06 to 121.05 min for female alates and from 68.00 to 85.92 min for queens. CONCLUSION: When applied topically, formic acid was significantly less toxic than bifenthrin to red imported fire ants. Although its fumigation toxicity was lower than that of dichlorvos, formic acid had about an order of magnitude higher toxicity to S. invicta than to other insects studied so far. It may be worth investigating the use of formic acid for managing imported fire ants. Published 2012 by John Wiley & Sons, Ltd.     

Development and challenges of green food in China

Green food in China refers to a wide array of primary and processed agricultural products that are safe, nutritious and of high quality for human consumption. Green food has been certified and produced following the principle of sustainability since the 1990s, making historic achievements in providing quality food, protecting the environment, increasing farmer income, and nurturing agricultural brands over the past 30 years in China. Today, the green food industry enters a steady-growth stage in terms of cultivation area, product number and sales. This article summarizes the history of the development of green food in China and current achievements, analyze major challenges that may hamper further development of the industry, and propose strategies to address these challenges, i.e., optimization of the food supply chain, deep food processing, and utilization of food wastes.     

In vitro micropropagation from plumular apices of Turkish cowpea (Vigna unguiculata L.) cultivar Akkiz

Multiple shoot formation from the plumular apices excised from mature embryos of cowpea cv. Akkiz was obtained after pulse treatment with 10 mg/l BAP for 5 days followed by culture on MS medium containing 0.25, 0.50, 0.75 and 1.00, 1.25 mg/l BAP – with or without 0.10 mg/l NAA. Callus induction and shoot regeneration was recorded on all cultures containing BAP with or without NAA. However, inclusion of 0.1 mg/l NAA had positive effect on callus diameter and shoot length. Maximum mean number of 7.11 shoots per explant were obtained on MS medium containing 1.00 mg/l BAP. Longer shoots were recorded on MS medium containing various concentration of BAP+ 0.1 mg/l NAA compared to those containing various concentrations of BAP singly. All shoots cultured on MS medium containing 1 mg/l BAP were rooted on MS medium containing 0.50 mg/l IBA. Rooted plants were acclimatized at room temprature in soil contained in pots. All plants flowered and set seeds in the greenhouse after 3 months.     

Small RNA deep sequencing reveals the presence of multiple viral infections in cucurbit crops in Guangdong,China

Viral diseases are among the most critical damaging factors that impose a global threat to the cucurbit industry.China is the world’s leading country for the production and consumption of cucurbits.Guangdong,a province in southern China dominated by the tropical and subtropical climate,favors the survival of different plant viruses and their vectors.Five main cucurbit crops showing various disease symptoms were surveyed and collected to identify viruses infecting cucurbits in Guangdong during 20...     

Two-year study on combining ability and heterotic potential in functional traits under salt stress in upland cotton (Gossypium hirsutum)

Salt tolerance is a physiologically and genetically complex trait controlled by multiple genes. To analyze the genetic basis of salt tolerance we evaluated 18 F₁ along with their nine parents under three salt stress levels i.e. control, 10 dS m⁻¹ and 15 dS m⁻¹ in the summer of 2017 and 2018. Data were recorded for the number of bolls, seed cotton yield, boll weight, Na⁺, K⁺, K⁺/Na⁺ ratio, H₂O₂, SOD, POD, CAT and TSP. Line × tester analysis indicated that the contribution of lines was greater than testers. Except for Na⁺, most of the traits were controlled by non-additive genes. With the rise of salt stress, SCA variances increased and were higher than GCA variances for most of the traits indicating the traits were controlled by a few largely dominant genes. KEHKSHAN, FH-118 and FH-114 were found good general combiner whereas the cross KEHKSHAN × FH-114 was a good specific combiner and also indicated significant better parent heterosis for most traits during two years under salt stress and can be utilized in a breeding programme for salt tolerance.