Effects of red (600 to 680 nanometers) and far red (700 to 760 nanometers) irradiances on Amaranthus retroflexus L. seeds indicate that synthesis of phytochrome in the red-absorbing form takes place in water-imbibed nongerminating seeds at 35 C. After 96 hours in darkness, conversion of about 0.10% phytochrome to the far red-absorbing form induces 50% germination. Continuous far red radiation a...

Germination of Potentilla norvegica L. (rough cinquefoil) seeds stimulated by fluorescent irradiations of nearly 24 hours was inhibited by ethylene at <1 microliter per liter. Sensitivity to ethylene inhibition was highest during and immediately after the irradiation. By delaying ethylene treatment until about a day after the light potentiation, seeds escaped the inhibition. Ethylene inhibition...

Three-year trials (2006-2008) were conducted in order to determine the influence of the herbicide diflufenican (trade name – Pelikan 50 CK) on certain biological traits of Bulgarian common bean cultivar Plovdiv 15 M. The herbicide was applied in the doses of 200, 250 and 300 ml/ha after the sowing and before the growth of the plants. It has been found that the traits related to the height of th...

anastrepha bezzii (diptera: tephritidae) larvae are common inside fruits of sterculia chicha (malvaceae) in minas gerais state, brazil. the seed dormancy and attack by a. bezzii of the native species s.chicha can be detrimental to seed germination and thus the natural spread of this plant. the objectives of the current study were to compare ecological observations of a. bezzii and s. chicha in ...

Laboratory studies were conducted with leaf powder of three plants to show the preservative effect for maintaining the quality of lentil seeds in storage. After processing and drying, seeds were preserved with different botanicals and stored them in earthen pots for eight months. Botanicals, such as whole leaf powder of neem (Azadirachta indica), dholkalmi (Ipmoea sepiara), and bishkatali (Poly...

Four new species, Macrocarpaea dies-viridis (Ecuador), M. luctans (Ecuador, Peru), M. lucubrans (Panama), and M. opulenta (Ecuador), and two natural hybrids, M. × acuminata (Costa Rica) and M. × mattii (Ecuador), are described. Macrocarpaea × acuminata Weaver (pro sp.) is recognized as a natural hybrid between M. subcaudata and M. valerii, rather than as a distinct species, and M. × mattii is d...

We investigated the effects of plant density on reproductive success for two insect-pollinated plant species—the native North American wildflower Penstemon digitalis (Foxglove-leaved Penstemon), and the showy introduced weed Hesperis matronalis (Dame's Rocket). We found no indication that local density (within 3.0 m) affected reproductive success (seeds per fruit, proportion fruit set, total se...

Seed size and toughness affect seed predators, and size-dependent investment in mechanical defence could affect relationships between seed size and predation. We tested how seed toughness and mechanical defence traits (tissue density and protective tissue content) are related to seed size among tropical forest species. Absolute toughness increased with seed size. However, smaller seeds had high...

Seed masting and production of empty seeds have often been considered independently as different strategies to reduce seed predation by animals. Here, we integrate both phenomena within the whole assemblage of seed predators (both pre and post-dispersal) and in two contrasting microsites (open vs. sheltered) to improve our understanding of the factors controlling seed predation in a wind-disper...