Trachypogon spicatus, formerly known as Trachypogon plumosus, is a dominant grass in some savannas of Northern South America. Its dispersal unit, like many other species of the Andropogoneae tribe, bears a hygroscopic awn which facilitates its establishment in favorable microsites. Some authors have previously proposed that there is a positive correlation between awn length and dispersal unit b...

This article reports experiments that explore the critical factors for gene flow in oilseed rape (Brassica napus) via the soil seedbank under Chinese farming systems. Research was carried out on 16 farmer s fields to estimate harvest seed losses after different planting methods and harvest timings, during the four components of the harvest operations. An additional field experiment was set up t...

the effects of environmental factors on germination and emergence of hoary cress seeds were examined in laboratory and field experiments. germinability of hoary cress under light/dark conditions (90%) was significantly higher than when seeds were incubated under continuous dark (78%). hoary cress could germinate in a broad range of temperatures (15/6, 20/10, 25/15, 30/15, and 35/20?c). the germ...

Sclerotia are the primary over wintering inoculum of Sclerotinia sclerotiorum (Lib.) de Bary. The effects of tillage on the primary inoculum are not well understood. The purpose of this research was to study sclerotial viability over time and between burial depths in soil, to identify bacteria colonizing and degrading the sclerotia, and determine whether these bacteria may be utilized as biolog...

Many studies have investigated the individual effects of sedimentation or inundation on the performance of wetland plants, but few have examined the combined influence of these processes. Wetland plants might show greater morphological plasticity in response to inundation than to sedimentation when these processes occur simultaneously since inundation can negate the negative effects of burial o...

[1] Natural pieces of wood provide a variety of ecosystem functions in streams including habitat, organic matter retention, increased hyporheic exchange and transient storage, and enhanced hydraulic and geomorphic heterogeneity. Wood mobilization is a critical process in determining the residence time of wood. We documented the characteristics and locations of 865 natural wood pieces (>0.05 m i...

The Thermal Emission Spectrometer (TES) on the Mars Global Surveyor spacecraft has detected deposits of coarse-grained, gray crystalline hematite in Sinus Meridiani, Aram Chaos, and Vallis Marineris. We argue that the key to the origin of gray hematite is that it requires crystallization at temperatures in excess of about 100 ◦C. We discuss thermal crystallization (1) as diagenesis at a depth o...

Dynamic environments like seagrass habitats are characterised by continuous local erosion and burial processes, which may induce seagrass decline if disturbances become too intense or frequent. We aim to quantify for Zostera noltii the resilience of both the edge of a meadow and individual propagules to local-scale burial and erosion events. In a set of mesocosm and in situ manipulation experim...

Wild almond (Amygdalus scoparia) is one of the most important species that provides a variety of ecological functions in the Zagros forest ecosystem. In this study, we investigated the effects of some seed treatments on the survival and growth of Amygdalus scoparia after seed planting at different aspects and elevations under natural conditions. The seed pretreatments consisted in soaking them ...