Morphological characterization and response of red flower rag leaf (Crassocephalum crepidioides Benth S. Moore) to organic and inorganic fertilizers and arbuscular mycorrhizal fungus

Red flower rag leaf (Crassocephalum crepidioides) is one of the underutilized vegetables consumed globally. Pot trials were conducted to characterize 15 morphologically distinct accessions of C. crepidioides and assess the effects of treatment combinations of eggshell, NPK 15:15:15, poultry manure and arbuscular mycorrhizal fungus(Glomus mosseae) as soil amendments on growth and yield-related characters of C. crepidioides. Thereafter, 48 seedlings of the best performing accession were transplanted into perforated polythene bags filled with 7 kg of heat-sterilized soil. The experiment was laid out in a completely randomized design with three replicates. Treatment combinations were incorporated into in the polythene bags 1 week after transplanting, while control plants received no amendments. The results showed that accession NH/GKB-15 had the highest plant height (29.83 cm), stem length (27.67 cm), number of leaves (15) and length of internode at node 3 (1.13 cm) and node 4 (1.17 cm). The growth and yield characters of this best performing accession (NH/GKB-15) in response to soil amendments showed that poultry manure produced the tallest plants (55.17 cm), longest and widest stems (48.35 and 0.66 cm), longest and widest leaves (16.39 and 6.26 cm, respectively), and higher number of inflorescence (2.13). With NPK 15:15:15 the seedlings did not survive. Poultry manure should therefore be utilized for better plant nutrition and faster growth of C. crepidioides seedlings as well as for safer consumption of the leafy vegetable.

Lead Bioaccumulation and Translocation in Herbaceous Plants Grown in Urban and Peri-Urban Soil and the Potential Human Health Risk

Lead (Pb) contamination risks to crops grown in urban and peri-urban soils is a great concern that should be better evaluated to define the Pb maximum levels in soils for safe cultivation and to identify suitable strategies to remediate Pb polluted urban soils. The objective of this work was to evaluate the potential risk for human health from the ingestion of the edible portions of barley, castor bean, common bean, Indian mustard, sorghum, spinach, and tomato grown in an unpolluted soil (initial Pb content 32.6 mg kg−1) spiked with 0, 300, 650, 1000 mg Pb kg−1, respectively. The potential possibility of using these plants to phyto-remediate the soil of Pb was also assessed. Pot trials were conducted for two years (2008 and 2009). Results highlighted that all the investigated species were able to attain growth to maturity in high Pb spiked soil, although Pb influenced dry matter accumulation. Even in soils with low Pb concentrations, Pb accumulated the edible parts. Noteworthy, even in untreated control soils, all tested species revealed a Pb concentration in the edible parts that was higher than the safe limit set by FAO/WHO. None of the investigated species were considered Pb hyperaccumulators, but all were shown to be potentially suitable for phyto-stabilization.

Mesotrione: a new preemergence herbicide option for wild radish (Raphanus raphanistrum) control in wheat

Wild radish is the most problematic broadleaf weed of Australian grain production. The propensity of wild radish to evolve resistance to herbicides has led to high frequencies of multiple herbicide resistant populations present in these grain production regions. The objective of this study was to evaluate the potential of mesotrione to selectively control wild radish in wheat. The initial dose response pot trials determined that at the highest mesotrione rate of 50 g ha−1, PRE application was 30% more effective than POST on wild radish. This same rate of mesotrione POST resulted in a 30% reduction in wheat biomass compared to 0% for the PRE application. Subsequent, mesotrione PRE dose response trials identified a wheat selective rate range of >100 and < 300 g ai ha−1 that provided greater than 85% wild radish control with less than 15% reduction in wheat growth. Field evaluations confirmed the efficacy of mesotrione at 100 to 150 g ai ha−1 in reducing wild radish populations by greater than 85% following PRE application and incorporation by wheat planting. Additionally, these field trials demonstrated the opportunity for season-long control of wild radish when mesotrione PRE was followed by bromoxynil POST. The sequential application of mesotrione, an HPPD-inhibiting herbicide, PRE followed by bromoxynil, a PS II-inhibiting herbicide POST has the potential to provide 100% wild radish control with no effect on wheat growth.

Using Rhizosphere Phosphate Solubilizing Bacteria to Improve Barley (Hordeum vulgare) Plant Productivity

On average less than 1% of the total phosphorous present in soils is available to plants, making phosphorous one of the most limiting macronutrients for crop productivity worldwide. The aim of this work was to isolate and select phosphate solubilizing bacteria (PSB) from the barley rhizosphere, which has other growth promoting traits and can increase crop productivity. A total of 104 different bacterial isolates were extracted from the barley plant rhizosphere. In this case, 64 strains were able to solubilize phosphate in agar plates. The 24 strains exhibiting the highest solubilizing index belonged to 16 different species, of which 7 isolates were discarded since they were identified as putative phytopathogens. The remaining nine strains were tested for their ability to solubilize phosphate in liquid medium and in pot trials performed in a greenhouse. Several of the isolated strains (Advenella mimigardefordensis, Bacillus cereus, Bacillus megaterium and Burkholderia fungorum) were able to significantly improve levels of assimilated phosphate, dry weight of ears and total starch accumulated on ears compared to non-inoculated plants. Since these strains were able to increase the growth and productivity of barley crops, they could be potentially used as microbial inoculants (biofertilizers).

Increasing root penetration into a different environment is more important than improving rooting depth

Deep rooting is often thought as a promising phenotype for resource extraction, but on soils with constraints, desired rooting depth was rarely observed. We hypothesised that if the genetic effect on root growth and rooting depth were separated from other effects, the determinants of root growth and rooting depth could be quantified. The conventional core-breaking method was used to measure root growth of wheat at two sites in two successive years under rain fed conditions. The Bayesian hierarchical nonlinear mixed models (HNLMMs) were employed to estimate root distribution, heritability and rooting depth. We found that root penetration from the non-sodic top to the sodic subsoil was most critical in determining rooting depth. Our study indicates that focusing on root-soil interaction at the transition layer where soil constraints start to emerge would lead to a more effective solution to develop resilient roots. Our work not only serves as a guide for selecting genotypes in pot trials, but also provides a theoretical support to breed advance crops with better soil adaptation.

Student Project: Horticultural protocols for experimental studies of eyebrights (Euphrasia, Orobanchaceae)

Parasitic plants are particularly challenging to cultivate as the growth conditions must be suitable for the parasite, the host, and their interaction. Here, we review our progress growing British native eyebrights (Euphrasia), a group of hemiparasitic plants found in diverse habitats in Britain and Ireland. We consider the protocols required to grow them under a range of conditions, including the laboratory, in pot trials, in cultivated fields, and in the wild. We highlight the need to use seed stratification to break seed dormancy, to replicate planting to overcome low seed viability, and to manage host plants to avoid competition. While Euphrasia can be successfully grown in different environments more work is required to develop reliable horticultural protocols for growing plants under natural conditions.

Influence of C14 Alkane Stress on Antioxidant Defense Capacity, Mineral Nutrient Elements Accumulation and Cadmium Uptake of Ryegrass

In order to explore the influence of C14 alkane on physiological stress responses, mineral nutrient elements uptake, cadmium (Cd) transfer and uptake characteristics of Lolium perenne L. (ryegrass), a series of pot trials were conducted which included a moderate level of Cd (2.182 mg·kg− 1) without (control) and with five levels of C14 alkane (V/m, 0.1%, 0.2%, 0.5%, 1%, 2%). Biomass and Cd content in the root and shoot, chlorophyll content, antioxidant enzymes activity, mineral nutrient elements in the shoot of ryegrass were determined at the end of the experiment. The results indicated that Cd uptake significantly elevated at 0.1% C14 alkane treatment, then gradually decreased with the increase of C14 alkane concentration. Compared with the control, chlorophyll content was significantly suppressed and malondialdehyde (MDA) concentration obviously increased. Superoxide dismutase (SOD) activity and catalase (CAT) activity significantly increased to prevent the C14 alkane stress. With the increased of C14 alkane, the Mn concentration gradually increased, Mg and Fe significantly decreased. Correlation analysis showed that Mn was positively correlated with SOD (with the exception of 2% treatment) and CAT (p < 0.01), and negatively correlated with Cd uptake (p < 0.01). It implied that the increase of Mn induced by C14 alkane stress was an important reason for the decrease of Cd uptake.

Plant-mediated rhizospheric interactions in rice-water spinach intercropping enhance Si uptake by rice

Aims Although biodiversity utilization in paddy fields has increased in recent years, silicon (Si) nutrition of rice in intercropping systems is poorly understood. On the basis of our previous study, the present research focused on deciphering the underlying mechanisms involved in rice and water spinach intercropping, which enhance Si uptake by rice.Methods We carried out a series of experiments including field, greenhouse, and incubation experiments to explore the underlying mechanisms.Results The field trials showed that rice-water spinach intercropping with different row ratios can increase Si concentration by 9.8%-52.6% and Si absorption by 34.7%-127.8% in rice leaves at ripening stage compared to rice monoculture. The pot trials further indicated that intercropping can promote rice to increase Si concentration in Si-deficient soil, with an increase of 35.9% in stems and 29.7% in leaves, and intercropping significantly increased soil water-soluble Si content by 168.1% compared to rice monoculture. Further research indicated that there was an interaction between rice roots and water spinach roots under intercropping conditions, which not only induced the up-regulated expression of Si transporter genes in rice roots (OsLsi1, OsLsi2) and stems (OsLsi6), but also stimulated rice roots to secrete more organic acids to increase Si availability in the soil. Moreover, water spinach root exudates helped the mobilization of Si in soil through proton efflux of roots. Conclusions Rice-water spinach intercropping can greatly enhance Si absorption of rice through several beneficial ways, which will have important practical significance for sustainable rice production, especially in Si-deficient soils.

Fusarium incarnatum: A Novel Leaf Spot Pathogen Isolated from Rosa indica in Pakistan

Fungal leaf spots disease is a main reason of rose (Rosa indica L.) crop failure in Pakistan. Isolation and identification of pathogen from rose plant was done by observing phenotypic characters which were further executed on molecular bases using ITS, EF and Bt2a/Bt2b primers. On these bases, pathogen was identified as Fusarium incarnatum. Then, Koch’s pathogenicity test was applied to confirm the virulence level of the isolated fungus by artificially inoculating it on R. indica seedlings in plate and pot trials. This study signifies the first report of F. incarnatum as a leaf spot pathogen of R. indica in Pakistan and highlights the need to explicate the management strategies of pathogen populations. © 2021 Friends Science Publishers

PLANT GROWTH POTENTIAL OF SALT TOLERANT ENDOPHYTE Pseudomonas Sihuiensis ISOLATED FROM CHICKPEA

Bacterial endosymbionts are well characterized for plant growth promotion. In this study, the root, nodules, and stem of the Cicer arietinum crop planted in a semi-arid zone were used as a source to isolate potential plant growth bacteria. The ability to grow under salt stress was determined, and the potential isolate was screened for plant growth promotion traits. The selected isolate was identified by the 16S rDNA method. Pot trials were conducted to know the ability of the isolate to promote plant growth in-vivo. Among various isolates obtained, a bacterial isolate obtained from root showed the ability to grow in the presence of 10 % Sodium fluoride (NaF). The isolate produced Indole Acetic acid in an amount of 72 mg per liter in production medium. The bacteria solubilized phosphate and produce exopolysaccharide (2.12 g per liter). The isolate was identified as Pseudomonas sihuiensis. The result of pot trials reveals that the endophyte promotes plant growth under stress conditions and may be used as a bio-fertilizer.