1. Ambrosia trifida L. (giant ragweed), an aggressive weed of US grain crops and indigenous to North America, colonizes no-tillage crop fields and undisturbed soils despite its large seed size and susceptibility to seed predation. Secondary seed dispersal is critical to seed survival and seedling establishment, yet mechanisms of secondary dispersal are poorly understood for such large-seeded we...

Micrometer-sized, monodisperse polystyrene (PS)/poly(styrene-co-sodium styrene sulfonate) (P(S-NaSS))/poly(n-butyl methacrylate) (Pn-BMA) composite particles having a ‘golf ball-like’ shape were prepared by seeded dispersion polymerization of n-butyl methacrylate with PS-core/P(S-NaSS)-shell seed particles with various shell thicknesses in the presence of dodecane droplets in a methanol/water (...

In this paper we derive the mass function of seed black holes that result from the central mass concentrated via disc accretion in collapsed haloes at redshift z ≈ 15. Using standard arguments including stability, we show that these pre-galactic discs can assemble a significant mass concentration in the inner regions, providing fuel for the formation and initial growth of super-massive black ho...

BT37 is a crown gall teratoma incited on tobacco by Agrobacterium tumefaciens containing pTi-T37, a nopaline-type Ti plasmid. Treatment of this cloned tumor tissue with kinetin at 1 mg/liter results in the formation of relatively normal-appearing shoots. These shoots can be induced to root and set viable seed. In contrast to BT37 tissue, the derived tissues are not phytohormone independent and ...

The seed maturation programme occurs only during the late phase of embryo development, and repression of the maturation genes is pivotal for seedling development. However, mechanisms that repress the expression of this programme in vegetative tissues are not well understood. A genetic screen was performed for mutants that express maturation genes in leaves. Here, it is shown that mutations affe...

Hybridisation and polyploidy are major forces contributing to plant speciation. Homoploid (2x) and heteroploid (3x) hybrids, however, represent critical stages for evolution due to disturbed meiosis and reduced fertility. Apomixis--asexual reproduction via seeds--can overcome hybrid sterility, but requires several concerted alterations of developmental pathways to result in functional seed form...

The aflatoxin-producing fungus Aspergillus flavus is a causal agent of preharvest contamination of food commodities such as oil seed crops worldwide. Peanut, corn and cottonseed are among the oil seeds that are susceptible to aflatoxin contamination during invasion of these crops by A. flavus. Contamination of agricultural commodities with aflatoxins can result in serious economic hardships to ...

Defining sustainable agricultural practices requires an understanding of both aboveand below-ground consequences to management strategies. While alternatives to biocides are sought for the control of weeds, insects and pathogens, biocide use will continue with the goal of reducing quantities used in an integrated approach. The impact of three fungicides on plant growth, seed yield, seed nutrien...

Considering the economic importance of chickpea (C. arietinum L.) seeds, it is important to understand the mechanisms underlying seed development for which a cDNA library was constructed from 6 day old chickpea embryos. A total of 8,186 ESTs were obtained from which 4,048 high quality ESTs were assembled into 1,480 unigenes that majorly encoded genes involved in various metabolic and regulatory...