Journal ArticleDOI
Plant Population Induced Growth Correlations in the Barley Plant Main Shoot and Possible Hormonal Mechanisms
E. J. M. Kirby,D. G. Faris +1 more
TLDR
It is suggested that plants grown at high densities had a high concentration of gibberellins (GA) in their tissues, which gave rise to starvation of the tip of the apex and earlier death of this region and, consequently, fewer spikelets.Abstract:
A morphogenetic study, from the first-leaf stage onwards, was made of barley plants grown at a range of plant populations from 50 to 1600 plants m~2. Increasing density reduced leaf number from 10-2 to 8 and caused stem internode elongation to start earlier at a lower node. Final stem length was reduced due to earlier cessation of growth. The lamina and sheath length of the lower leaves was increased with increasing density, and lamina width was de creased. At the highest density the apex reached the double ridge stage 6 days earlier than at the lowest density, and this difference persisted throughout the development of the apex. The rate of primordium production was little affected by density, but the duration was markedly affected. Primordium production stopped abruptly, first at the highest density, and then successively at the lower densities. At this stage changes were seen at the tip of the apex, and eventually the 10 distal primordia died. There were small differences in the length of shoot apex or ear during growth, but earlier cessation of growth in the higher densities led to a shorter ear. Growth of the internodes of the floral apex started first at the high density. These observations suggest that plants grown at high densities had a high concentration of gibberellins (GA) in their tissues. The promotion of apex development by the higher concentra tion of GA gave rise to earlier competition for nutrients diffusing through the apex. This lead to starvation of the tip of the apex and earlier death of this region and, consequently, fewer spikelets. Differences in the light environment of the plants, either intensity or red/far red ratio, most probably brought about the differences in GA.read more
Citations
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In Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning
TL;DR: The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase, linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin.
Book ChapterDOI
Lodging in Wheat, Barley, and Oats: The Phenomenon, its Causes, and Preventive Measures
TL;DR: The chapter describes two types of lodging: stem lodging and root lodging and examines various causes of lodging and the effects of lodging on crop development and yield.
Journal ArticleDOI
Tillering in grasses—its significance and control*
TL;DR: The physiological results are used to suggest reasons for the commonly found apparent inability of heavily fertilized perennial ryegrass (Lolium perenne) swards to regrow after cutting at the inflorescence-emergence stage of growth.
Journal ArticleDOI
The physiological response of winter wheat to reductions in plant density
TL;DR: It is proposed that better radiation distribution through the canopy and increased canopy nitrogen ratio were the causative mechanisms for this increase in RUE.
References
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Journal ArticleDOI
Effects of Gibberellins on Plant Growth and Development
TL;DR: The results have led to the conclusion that the endogenous auxins of plants are limited in their effects, and that growth is correspondingly limited, by 'an inhibitory system'.
Journal ArticleDOI
The developmental relationship between shoot apex and growth pattern of leaf blade in diploid maize
Journal ArticleDOI
The effect of plant density upon the growth and yield of barley
TL;DR: Ear emergence and ear number were affected both by variety and density, and there was a variety effect on seedling establishment but there was no further compensation for tiller number.
Journal ArticleDOI
The Physiology of Leaf Growth
and E C Humphries,A W Wheeler +1 more
TL;DR: The physiology of leaf growth has not previously been reviewed in full, but part of the subject was considered in a symposium on The Growth of Leaves and the discovery of gibberellins renewed interest in leaf-growth substances.
Journal ArticleDOI
The effect of sowing date and plant density on barley
TL;DR: Proctor and Maris Puma barleys were sown in October, early March, and late April at low and high fertilizer levels, and nitrogen data indicated a loss of nitrogen from the plant at high densities.