We investigated floral initiation in the long-day monocot Lolium temulentum, strain Ceres, by culturing apices explanted from photoperiodically induced plants at various times after one inductive long day onto medium with, and without, gibberellin. Apices cultured on the first day after the inductive long day usually required gibberellin in the medium to initiate floral morphogenesis while apic...

Nitrous oxide (N2 O) emissions are subject to intra- and interannual variation due to changes in weather and management. This creates significant uncertainties when quantifying estimates of annual N2 O emissions from grazed grasslands. Despite these uncertainties, the majority of studies are short-term in nature (<1 year) and as a consequence, there is a lack of data on interannual variation in...

Antifreeze proteins (AFPs), found in certain organisms enduring freezing environments, have the ability to inhibit damaging ice crystal growth. Recently, the repetitive primary sequence of the AFP of perennial ryegrass, Lolium perenne, was reported. This macromolecular antifreeze has high ice recrystallization inhibition activity but relatively low thermal hysteresis activity. We present here a...

Patterns of resource availability and heterogeneity shape the composition, productivity, and dynamics of plant assemblages in a wide variety of terrestrial ecosystems. Despite this, the responses of plant assemblages to simultaneous changes in the availability and heterogeneity of more than a single resource are virtually unknown. To fill this gap, microcosms consisting of assemblages formed by...

As a preliminary experiment to measuring milksolids (fat plus protein) production of dairy cattle grazing swards containing different levels of white clover (Trifolium repens L.) nine Jersey and nine Friesian cattle housed indoors during late lactation and fed diets containing either 20, 50 or 80% white clover with the balance perennial ryegrass (Lolium perenne L.). During the first 10 day meas...

Partially purified ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) was isolated from diploid and tetraploid cultivars of ryegrass (Lolium perenne L.) using two separate methods. The apparent K(m) (CO(2)) values for the enzymes prepared by either method did not differ significantly between diploid and tetraploid when assayed by two separate techniques. The unpurified enzymes from freshly lys...

BACKGROUND AND AIMS To improve the management of grass communities, early plant development was compared in three species with contrasting growth forms, a caespitose (Lolium perenne), a rhizomatous (Poa pratensis) and a caespitose-stoloniferous species (Agrostis stolonifera). METHODS Isolated seedlings were grown in a glasshouse without trophic constraints for 37 d (761 degrees Cd). The appea...

The development of preparation techniques that include freeze fracturing provide an ideal method for studying the differentiation of plant tissues in the scanning electron microscope. This is illustrated with reference to tapetal development in Catananche caerulea, which has a plasmodial tapetum, and in Lolium perenne, which has a secretory tapetum.