Germination ecology of Chenopodium album L. and implications for weed management

Seed Germination Ecology of Sonchus asper and Sonchus oleraceus in Queensland Australia

Sonchus asper and S. oleraceus are among the most problematic broadleaf weeds in eastern cropping systems of Australia. This study investigated the seed germination ecology of S. asper and S. oleraceus. The study hypothesized that S. asper may have greater ecological advantages under adverse environmental conditions compared to S. oleraceus. Results showed that S. asper consistently outperformed S. oleraceus across different light regimes and stress conditions. At a lower temperature regime of 15/5 °C, seed germination of S. oleraceus decreased by 19% compared to S. asper. Germination of S. oleraceus significantly declined under dark conditions, while over 90% of S. asper seeds germinated under both light/dark and dark conditions. Under water stress (osmotic potential of -0.4 MPa), S. oleraceus germination dropped by 74% compared to S. asper, indicating S. asper's superior drought tolerance. Both species exhibited moderate salinity tolerance (40 mM NaCl) to germinate, highlighting their potential to invade saline cropping environments. The burial study revealed that S. oleraceus had higher germination at the soil surface, but no germination occurred from 4 cm, while 23% of S. asper seeds still emerged from that depth. The burial depth required to inhibit 50% emergence of S. asper and S. oleraceus was 3.3 cm and 0.3 cm, respectively. These findings highlight S. asper's greater adaptability to low temperatures, burial depth, and stress conditions than S. oleraceus. The insights from this study can inform agronomic strategies, including tillage depth and mulching, to mitigate the impact of these invasive species on Australian cropping systems.

The inhibitory potential of green manure return on the germination and seedling growth of Eleusine indica L

Trifolium repens L. (white clover) and Lolium perenne L. (ryegrass) are green manures widely used in conservation tillage systems worldwide. Eleusine indica L. (goosegrass) is a globally recognized noxious weed. Herein, we investigated the effects of aqueous extracts, decomposed liquids, and different straw-to-soil ratios on the germination and growth of goosegrass. The results showed that high concentrations (≥ 30%) of aqueous extracts or decomposed liquids of both green manures significantly inhibited germination-related parameters of goosegrass. The strongest inhibitory effect was observed for the 7-day decomposition treatment, and white clover's inhibitory effect was greater than ryegrass's. A pot experiment showed that non-photochemical quenching, catalase, and peroxidase activity levels of goosegrass leaves were significantly increased. At the same time, the net photosynthetic rate significantly decreased. Seedling growth was inhibited when the straw-to-soil ratio was greater than 3:100. The ryegrass treatments inhibited goosegrass seedlings more than the white clover treatments. This study demonstrated the inhibitory potential of white clover and ryegrass straw return on seed germination and seedling growth of goosegrass. The study has also helped to identify weed-resistant substances in these green manures so that their weed-control properties can be used more effectively and herbicide usage can be reduced.

Exploring the multifunctional roles of quantum dots for unlocking the future of biology and medicine

With recent advancements in nanomedicines and their associated research with biological fields, their translation into clinically-applicable products is still below promises. Quantum dots (QDs) have received immense research attention and investment in the four decades since their discovery. We explored the extensive biomedical applications of QDs, viz. Bio-imaging, drug research, drug delivery, immune assays, biosensors, gene therapy, diagnostics, their toxic effects, and bio-compatibility. We unravelled the possibility of using emerging data-driven methodologies (bigdata, artificial intelligence, machine learning, high-throughput experimentation, computational automation) as excellent sources for time, space, and complexity optimization. We also discussed ongoing clinical trials, related challenges, and the technical aspects that should be considered to improve the clinical fate of QDs and promising future research directions.

Genetic variation of Amaranthus retroflexus L. and Chenopodium album L. (Amaranthaceae) suggests multiple independent introductions into Iran

Amaranthus retroflexus L. and Chenopodium album L. (Amaranthaceae) are weedy plants that cause severe ecological and economic damage. In this study, we collected DNA from three different countries and assessed genetic diversity using inter-simple sequence repeat (ISSR) markers. Our analysis shows both weed species have low genetic diversity within a population and high genetic diversity among populations, as well as a low value of gene flow among the populations. UPGMA clustering and principal coordinate analysis indicate four distinct groups for A. retroflexus L. and C. album L. exist. We detected significant isolation-by-distance for A. retroflexus L. and no significant correlation for C.album L. These conclusions are based data from 13 ISSR primers where the average percentage of polymorphism produced was 98.46% for A. retroflexus L. and 74.81% for C. album L.These data suggest that each population was independently introduced to the location from which it was sampled and these noxious weeds come armed with considerable genetic variability giving them the opportunity to manifest myriad traits that could be used to avoid management practices. Our results, albeit not definitive about this issue, do not support the native status of C. album L. in Iran.