Ecophysiological responses of three native herbs to phytotoxic potential of invasive Acacia melanoxylon R. Br.

Acacia melanoxylon R. Br. (Blackwood) is a native Australian species that has invaded woodlands and degraded natural habitats in the north western Iberian Peninsula (Galicia), Spain. Several phenolic (p-hydroxybenzoic, vanillic, p-coumaric, syringic, protocatequic, ferulic acids) and flavonoids (catechin, luteolin, rutin, apigenin, and quercetin) were identified from methanol extracts of flowers and phyllodes of A. melanoxylon by HPLC. Flowers and phyllodes of A. melanoxylon were soaked separately in the water in a ratio of 1:1 (w/v) for 24 h to prepare aqueous extracts (100, 75, 50 and 25%) and distilled water was used as control. The seeds of three native plants, cocksfoot (Dactylis glomerata), perennial ryegrass (Lolium perenne), common sorrel (Rumex acetosa) and a general test crop lettuce (Lactuca sativa) were grown in perlite culture and aqueous extracts of A. melanoxylon (flowers and phyllodes) were applied exogenously at various concentrations. A. melanoxylon flowers extract (100%) inhibited the shoot length of D. glomerata and L. perenne by 31 and 20% of the control, respectively. Leaf and root fresh weights of L. perenne, D. glomerata, and L. sativa were reduced after treatment with acacia flowers and phyllodes extract. Leaf relative water content of D. glomerata and L. perenne was reduced by acacia flowers and phyllodes extract at all concentrations. Both extracts reduced leaf osmotic potential in D. glomerata, L. perenne and L. sativa. Quantum efficiency of open PSII reaction centers (F_v/F_m) and quantum yield (ΦPSII) of photosystem II were decreased in L. perenne, D. glomerata; R. acetosa and L. sativa after treatment with acacia flowers/phyllodes extract at 100% concentration. Acacia flowers and phyllodes extract (100%) inhibited the qP level during all 6 days in D. glomerata, L. perenne, R. acetosa and L. sativa. A significant reduction in NPQ was observed during different days in all four plant species due to Acacia flowers and phyllodes extract (100%). The δ¹³C ratios were less negative in L. perenne, D. glomerata and L. sativa as compared to the control. A. melanoxylon flowers and phyllodes extract (100%) significantly reduced leaf protein contents in D. glomerata, L. perenne and in L. sativa.     

Preparation and evaluation of chicken embryo-adapted fowl adenovirus serotype 4 vaccine in broiler chickens

The current study was planned to develop an efficient vaccine against hydropericardium syndrome virus (HSV). Currently, formalin-inactivated liver organ vaccines failed to protect the Pakistan broiler industry from this destructive disease of economic importance. A field isolate of the pathogenic hydropericardium syndrome virus was adapted to chicken embryos after four blind passages. The chicken embryo-adapted virus was further serially passaged (12 times) to get complete attenuation. Groups of broiler chickens free from maternal antibodies against HSV at the age of 14 days were immunized either with 16th passage attenuated HSV vaccine or commercially formalized liver organ vaccine. The antibody response, measured by enzyme-linked immunosorbent assay was significantly higher (P < 0.05) in the group immunized with the 16th passage attenuated HSV vaccine compared to the group immunized with liver organ vaccine at 7, 14, and 21 days post-immunization. At 24 days of age, the broiler chickens in each group were challenged with 10^3.83 embryo infectious dose₅₀ of pathogenic HSV and were observed for 7 days post-challenge. Vaccination with the 16th passage attenuated HSV gave 94.73% protection as validated on the basis of clinical signs (5.26%), gross lesions in the liver and heart (5.26%), histopathological lesions in the liver (1.5 ± 0.20), and mortality (5.26%). The birds inoculated with liver organ vaccine showed significantly low (p < 0.05; 55%) protection estimated on the basis of clinical signs (40%), gross lesions in the liver and heart (45%), histopathological lesions in the liver (2.7 ± 0.72), and mortality (35%). Birds in the unvaccinated control group showed high morbidity (84%), mortality (70%), gross (85%), and histopathological lesions (3.79 ± 0.14) with only 10% protection. In conclusion, this newly developed HSV vaccine proved to be immunogenic and has potential for controlling HSV infections in chickens.     

巴基斯坦波特瓦尔高原农业生态系统中灰鹧鸪(Francolinus pondicerianus)的种群生物学(英文)

我们于2009年在巴基斯坦波特瓦尔高原地区对农业生态系统中灰鹧鸪(Francolinus pondicerianus)的种群生物学进行了研究。该地区是灰鹧鸪在巴基斯坦的重要分布区之一。灰鹧鸪在作物区和灌丛林地的密度分别为每公顷1.59±0.39和0.87±0.14只,并且两种生境中的密度在季节间均稍有浮动。灰鹧鸪在由Desmostachia bipinnata、Acacia modesta、Imperata cylindrical、枣树(Zizipus jujuba)及大戟属(Euphorbia)等植物组成的植被地面营巢。产卵期为春夏两季,平均产卵期长约6±0.36天(5–7天),平均窝卵数为7±0.36枚(6–8枚)。平均孵卵期为20.6±0.50天(19–22天)。所记录的42枚卵中,32枚成功孵化(成功率76.19%),平均孵化率为每窝5.33±1.22枚。离巢雏鸟数约为每窝3.83±0.83只(离巢率63.08%)。该鸟种为杂食性,亦食天牛。从该鸟的食物中鉴别出10个种类,包括 7 种植物:珍珠粟(Pennisetum typhoideum)、高粱(Sorghum bicolor)、假高粱(S.halepense)、牧豆树(Prosopis juliflora)、绿豆(Phaseolus radiates)、尖刺红花(Carthemus axycantha)及金合欢属(Acacia)某种植物,2种昆虫:家白蚁(Coptotermes formosanus)及红褐林蚁(Formica rufa),以及砂砾。     

Impact of Various Ratios of Nitrogen and Sulfur on Maize and Soil pH in Semiarid Region

Nitrogen and sulfur play an important role in maize production. The aim of this study was to evaluate the effect of nitrogen (N) and sulfur (S) levels applied in various ratios on maize hybrid Babar yield at Peshawar in 2011 and 2013. Four N levels (120, 160, 200 and 240 kg N ha^?1) and four S levels (20, 25, 30 and 35 kg S ha^?1) were applied in three splits: a, at sowing; b, V8 stage; c, VT stage in ratios of 10:50:40, 20:50:30 and 30:50:20. Grains ear^?1, thousand grain weight, grain yield ha^?1 and soil pH were significantly affected by years (Y), N, S and their ratios, while no effect of N, S and their ratios was noted on ears plant^?1. Maximum grains ear^?1 (390), thousand grain weight (230.1 g) and grain yield (4119 kg ha^?1) were recorded in 2013. N increased grains ear^?1 (438), thousand grain weight (252 g) and grain yield (5001 kg ha^?1) up to 200 kg N ha^?1. Each increment of S increased grains ear^?1 and other parameters up to 35 kg S ha^?1, producing maximum grains ear^?1 (430), thousand grain weight (245 g) and grain yield (4752 kg ha^?1), while soil pH decreased from 8.06 to 7.95 with the application of 35 kg S ha^?1. In the case of N and S ratios, more grains ear^?1 (432), heavier thousand grains (246.7 g) and higher grain yield (4806 kg ha^?1) were observed at 30:50:20 where 30% of N and S were applied at sowing, 50% at V8 and 20% at VT stage. It is concluded that 200 kg N ha^?1 and 35 kg S ha^?1 applied in the ratio of 30% at sowing, 50% at V8 and 20% at VT stage is recommended for obtaining a higher yield of maize hybrid Babar.     

Testing the role of allelochemicals in different wheat cultivars to sustainably manage weeds

Background

Selecting wheat varieties with allelopathic potential or high competitiveness against weeds is a sustainable solution for organic farming to eliminate the use of synthetic herbicides. Wheat is one of the most economically important crops. This study focuses on screening the allelopathic or competitive potential of four wheat cultivars, Maurizio, NS 40S, Adesso and Element, on two weeds of interest due to acquired herbicide resistance, Portulaca oleracea and Lolium rigidum, through germination and growth bioassays and the identification and quantification of benzoxazinoids (BXZs) and polyphenols (phenolic acids and flavonoids).

Results

The different cultivars showed different abilities to manage surrounding weeds and different capacity to exude or accumulate specialized metabolites in the presence of those weeds. Furthermore, each cultivar behaved differently depending on the weed present in the medium. The most efficient cultivar to control the tested monocot and dicot weeds was Maurizio, as it effectively controlled germination and growth of L. rigidum and P. oleracea while exuding large amounts of benzoxazinones through the roots, especially the hydroxamic acids 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one and dihydroxy-2H-1,4-benzoxaxin-3(4H)-one. By contrast, NS 40S, Adesso and Element showed the potential to control the growth of just one of the two weeds through allelopathy or competition.

Conclusion

This study reveals that Maurizio is the most promising wheat cultivar for sustainable weed control, and that the screening of crop varieties with allelopathic potential, which results in the displacement of synthetic herbicides, is an immediate solution in ecological and sustainable agriculture. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Horizontal gene transfer of a syp homolog contributes to the virulence of Burkholderia glumae

Horizontal gene transfer (HGT) has been proved a major driving force in prokaryotic evolution. However, the molecular functions of these transferred genes in pathogenic bacteria especially plant pathogenic bacteria are still not fully investigated. In this study, the whole-genome in silico analysis was performed and found a syringopeptin synthetase (syp) homolog in Burkholderia glumae, which can cause bacterial panicle blight in rice, was predicted to be horizontally transferred from Pseudomonas ancestor with solid confidence by phylogenetic analysis. The comprehensive molecular experiments were performed to study the potential role of this gene in B. glumae. Inoculation of rice panicles with the syp mutant resulted in 60% lower disease index compared with the wild type (WT) parent strain, suggesting the requirement of syp for the full virulence of B. glumae. Chromatography analysis of exudates from B. glumae showed suppression of synthesis of metabolites analogous to syringopeptin in the mutants. All these data raise the possibility of HGT phenomenon in shaping the virulence and adaptation of B. glumae over evolutionary time.     

Two new antioxidant bergenin derivatives from the stem of Rivea hypocrateriformis

Two new bergenin derivatives, named rivebergenin A and B (1, and 2), together with two known compounds, bergenin (3) and norbergenin (4) were isolated from the stem of Rivea hypocrateriformis (Desr.) Choisy. The structures of the new compound have been assigned from ¹H and ¹³C NMR spectra, DEPT, and by 2D COSY, HMQC, and HMBC experiments. Compounds 1-4 showed the strong antioxidant activity.     

Effect of Azospirillum and Azotobacter Species on the Performance of Cherry Tomato under Different Salinity Levels

Abiotic stress has a negative impact on plant physiology, influencing the overall growth and development of plant crops. Saline stress is one of the most serious environmental issues limiting crop plant production. Biofertilizers are reparative elements used in soil to increase tolerance to salinity and drought stress. We investigated the effect of salinity stress on qualitative and quantitative characteristics of cherry tomato plants (Lycopersicon esculentum cerasiforme) with biofertilizer application 0, 15 and 30 days after transplanting in this study. After different days of transplantation, different levels of salinity (0, 50, 100, and 150?mM) were used with biofertilizer (Azospirillum sp. and Azotobacter sp.) application (0, 15 and 30 days). The salinity (150?mM NaCl) significantly affected the studied variables, which were recorded with minimum levels of leaf area (52.42?cm²), root length (6.54?cm), fresh root weight (13.64?g), yield (6.52 tons/ha), leaf chlorophyll content (36.11?mg/m²) and maximum levels of total soluble solids (TSS, 8.87 °Brix). Control samples had higher leaf area (58.35?cm²), root length (15.23?cm), fresh root weight (17.86?g), yield (9.39 tons/ha), leaf chlorophyll content (44.09?mg/m²), and lower TSS (7.93 °Brix). Plants that received biofertilizer (15 days after transplanting) had higher plant height (73.41?cm), stem diameter (0.74?cm), leaf area (61.16?cm²), root length (15.35?cm), fresh root weight (18.38?g), root dry matter (60.41%), yield (10.43?t/ha), leaf chlorophyll content (42.55?mg/m²), fruit dry matter content (10.12?g), pH 4.52, and TSS (9.30 °Brix). The minimum plant height (51.33?cm), stem diameter (0.55?cm), leaf area (49.60?cm²), root length (7.04?cm), fresh root weight (12.76?g), root dry matter (42.16?g), yield (5.15 tons/ha), leaf chlorophyll content (35.18?mg/m²), fruit dry matter content (6.59?g), pH 4.27 and TSS (7.55 °Brix) were recorded in plants with no application of biofertilizer. The present study revealed that most growth and quality variables were negatively affected by salinity except for TSS, which showed positive effect with application of 150?mM of NaCl. Biofertilizer application at 15 days significantly influences the quantitative and qualitative attributes of cherry tomato under different levels of salinity.