The aim of the present work was to study the response of two sunflower genotypes (cultivated sunflower Helianthus annuus cv. 1114 and newly developed genotype H. annuus × Helianthus argophyllus) to Pb medium-term stress and the role of exogenously applied EDTA in alleviating Pb toxicity in hydroponics. Plant growth, morpho-anatomical characteristics of the leaf tissues, electrolyte leakage, tot...

Sunflower (Helianthus annuus L.), with its high oil quality, is one of the major and most valuable oilseed crops in the world. Sunflower rust, caused by Puccinia helianthi Schw., is one of the major foliar diseases of sunflower. The pathogen is present wherever sunflower is grown in the world and causes important yield losses when severe epidemics occur. The objective of this study was to ident...

Ten self-fertile commercial sunßowers cultivars were evaluated for seed set with and without exposure to bees. In the Þrst planting, the number of foraging honey bees was smaller than in the second, and seed set for most cultivars did not differ between those bagged to exclude bees and ones that were open pollinated. In the second planting, however, a majority of cultivars had significantly gre...

Proline concentration has been often suggested as an indicator of osmotic stress. A better understanding of the genetics of this trait is however needed. In the present study, proline concentration has been assessed, together with root and stem growth, potassium, calcium and total soluble sugars concentration and stress injury symptoms, in seedlings of sunflower hybrids and their parents grown ...

The limitations of conventional extracellular recording and intracellular recording make high-resolution multisite recording of plant bioelectrical activity in situ challenging. By combining a cooled charge-coupled device camera with a voltage-sensitive dye, we recorded the action potentials in the stem of Helianthus annuus and variation potentials at multiple sites simultaneously with high spa...

After sunflower seeds were exposed to space conditions, various mutant plants were screened from the descendent plants. The morphological characters of plants changed in flower color from golden to yellow, light yellow, or even to yellowish green. The ligulate petals of the unisexual floret broadened, or became thin, while the short tubular petals of bisexual floret elongated to some exten...

The genic view of the process of speciation is based on the notion that species isolation may be achieved by a modest number of genes. Although great strides have been made to characterize 'speciation genes' in some groups of animals, little is known about the nature of genic barriers to gene flow in plants. We review recent progress in the characterization of genic species barriers in plants w...

In the USA, cultivated sunflower (Helianthus annuus) is often sympatric with wild H. annuus, which is an agricultural weed that grows along roadsides and in other disturbed sites. We found that crop-to-wild gene flow was common (~5-40% hybrids) when wild plants occurred within <1,000 m of the crop, and crop-specific genetic markers persisted in wild populations for many generations. Crop-to-wil...

Here, we characterized silicon (Si) uptake and xylem loading in Oryza sativa, Zea mays, Helianthus annuus and Benincase hispida in a series of hydroponic experiments. Both active and passive Si-uptake components co-exist in all the plants tested. The active component is the major mechanism responsible for Si uptake in O. sativa and Z. mays. By contrast, passive uptake prevails in H. annuus and ...