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Growth Variables (growth + variable)

Distribution by Scientific Domains

Life Sciences	44%
Earth and Environmental Science	22%

Selected Abstracts

Early postnatal growth variables are related to morphologic and functional ophthalmologic outcome in children born preterm

ACTA PAEDIATRICA, Issue 5 2010
M Hök-Wikstrand
Abstract Aim:, To evaluate the association between gestational age (GA), early and late postnatal growth variables and ophthalmologic outcome in ex-preterm children. Methods:, Children (GA < 32 weeks, n = 66), previously examined regarding insulin-like growth factor 1 (IGF-1) serum concentrations in relation to ROP, underwent ophthalmologic examination at median 5.6 years. Weight, height, and head circumference (HC) were measured and expressed as SDS. Growth variables were analysed in relation to ophthalmologic outcome. Results:, At follow-up 74% had some ophthalmologic abnormality and 17% had visual impairment. Poor visual acuity was correlated with low GA (rs = 0.29, p = 0.019), low weight at 32 weeks (rs = 0.30, p = 0.013), and low weight (rs = 0.37, p = 0.0025), height (rs = 0.41, p = 0.0007) and HC (rs = 0.55, p < 0.0001) at follow-up. Hyperopic children (25%) had low neonatal IGF-1 (p = 0.0096) and HC at follow-up (p = 0.022). Poor visual perception was correlated with low early weight (rs = 0.38, p = 0.0036) and HC at follow-up (rs = 0.39, p = 0.0024). Head circumference at follow-up was correlated with GA (rs = 0.40, p = 0.0012), neonatal IGF-1 (rs = 0.37, p = 0.0031), and early weight (rs = 0.27, p = 0.035). Conclusions:, In very preterm children, early and later postnatal growth is closely related to visual acuity and perception at follow-up. In addition, IGF-1 concentrations and early growth are correlated with head circumference and refraction at follow-up. [source]

Are more productive varieties of Paspalum dilatatum less tolerant to drought?

GRASS & FORAGE SCIENCE, Issue 3 2010
L. L. Couso
Abstract Paspalum dilatatum Poir., is a perennial C4 grass widely distributed in the Argentinean Pampas. The response to water availability for materials developed with forage-production purposes is unknown. We hypothesized that genetic differences between commercial varieties are reflected in their regrowth capacity under water stress. The effect of five levels of constant water supply on three plant varieties (two derived from apomictic materials: ,Relincho' and ,Alonso' and one from sexually-derived material: ,Primo') were examined in the greenhouse. Leaf- and plant-response traits were followed during 38 d after a single defoliation event. Seven response variables were measured: three of them were morphogenetic (leaf elongation rate, leaf appearance rate and leaf elongation duration) and four were structural (number of live leaves, lamina length, tiller biomass and tiller production). The sexual material showed higher values for growth variables than the apomictic varieties (leaf elongation rate, leaf length and tiller biomass) across the environmental range. Apomictic varieties showed a proportionally similar drought response to the sexual material for the seven variables. No intra-specific trade-off (statistical interaction) was found between growth under high water availability conditions and drought tolerance. [source]

Effects of the timing of initial feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvae

JOURNAL OF FISH BIOLOGY, Issue 6 2009
L. Zhang
The effects of delayed first feeding on growth and survival of spotted mandarin fish Siniperca scherzeri larvae were examined under controlled conditions. Morphometric characters [yolk-sac volume, oil globule volume, head depth (HD), body depth (BD), eye diameter (ED), musculature height (MH), mouth diameter (MD) and total length (LT)], body mass (M), specific growth rate (SGR) and survival were evaluated under different first-feeding time (2, 3, 4 and 5 days after hatching). Larvae began to feed exogenously at 2 days after hatching (DAH) and the point of no return (PNR) occurred between 5 and 6 DAH at 23° C, range ±1·0° C. The yolk volume of larvae first-fed at 2 days had a significant difference compared with that of larvae first-fed at 3, 4 and 5 days on 3 and 4 DAH. The larvae first-fed at 2 days achieved comparatively better growth performance than that of 3, 4 and 5 days. On 5 DAH, all morphometric characters had significant differences between 2 and 5 days and 2 and 4 days initial feeding, respectively. Total mortality was recorded on 9 DAH for the larvae first-fed at 5 days. On 12 DAH, significant differences were observed between 2 and 4 days and 3 and 4 days initial feeding for all morphometric characters. From 16 DAH to the end of experiment, all growth variables of the larvae first-fed at 2 days were significantly higher than those in other treatments. The SGR (2,9 DAH) first-fed at 2 and 3 days were significantly higher than 4 and 5 day treatments, and the SGR (9,16 DAH) first-fed at 2 days was significantly higher than 3 and 4 day treatments. There was no significant difference, however, of SGR (16,28 DAH) among treatments. Survival rate was significantly higher at 2 days initial feeding (27·42%) when compared with 3 (15·96%) and 4 days (7·92%) initial feeding at the end of experiment. The present study suggests that the first feeding of S. scherzeri larvae should be initiated at 2 days after hatching for achieving good growth and survival. [source]

Modelling the relationship between sexual reproduction and rhizome growth in Posidonia oceanica (L.) Delile

MARINE ECOLOGY, Issue 4 2006
Sebastiano Calvo
Abstract The relationship between flowering and growth performance of Posidonia oceanica (L.) Delile in meadows distributed along the south-eastern coast of Sicily (Italy) was investigated by means of a statistical model (generalized linear mixed model) combined with the lepidochronological analysis. Over a 28-year period, 67 floral stalk remains were observed. The highest flowering index was recorded in lepidochronological year 1998 (10.1%) and the Inflorescence Frequency per age showed a clear decrease corresponding to 15-year-old shoots. The sexual reproductive event had positive effects on rhizome elongation (cm year,1) and leaf production (no. leaves year,1) in the same flowering year, whilst no effect on the rhizome production (mg year,1) was observed. Rhizome growth variables showed significant negative lagged responses in the two years following flowering. On the whole, we calculated that the effect exerted by flowering, in terms of loss on rhizome elongation and production, was about 27% and 38%, respectively. Although it has been demonstrated that recovery from the stress induced by sexual reproduction is limited to the two years after flowering, the magnitude of the reproductive cost may become quite considerable especially in comparison with the whole lifespan of individual shoots. [source]

Simulations of virtual plants reveal a role for SERRATE in the response of leaf development to light in Arabidopsis thaliana

NEW PHYTOLOGIST, Issue 3 2007
Karine Chenu
Summary ,,The SERRATE gene (SE) was shown to determine leaf organogenesis and morphogenesis patterning in Arabidopsis thaliana. The se-1 mutant was used here to investigate the role of SE in leaf development in response to incident light. Virtual plants were modelled to analyse the phenotypes induced by this mutation. ,,Plants were grown under various levels of incident light. The amount of light absorbed by the plant was estimated by combining detailed characterizations of the radiative environment and virtual plant simulations. ,,Four major changes in leaf development were induced by the se-1 mutation. Two constitutive leaf growth variables were modified, with a lower initial expansion rate and a higher duration of expansion. Two original responses to a reduced incident light were identified, concerning the leaf-initiation rate and the duration of leaf expansion. ,,The se-1 mutation dramatically affects both changes in the leaf development pattern and the response to reduced incident light. Virtual plants helped to reveal the combined effects of the multiple changes induced by this mutation. [source]

Correlation between leaf growth variables suggest intrinsic and early controls of leaf size in Arabidopsis thaliana

PLANT CELL & ENVIRONMENT, Issue 11 2005
SARAH J. COOKSON
ABSTRACT Leaf development is affected by both internal (genetic) and external (environmental) regulatory factors. The aim of this work was to investigate how leaf growth variables are related to one another in a range of environments. The leaf growth variables of wild-type Arabidopsis thaliana and leaf development mutants (ang4, ron2-1, elo1, elo2 and elo4) were studied under different incident light treatments (light and shade). The leaves studied were altered in various leaf development variables, such as the duration of expansion, relative and absolute expansion rates, epidermal cell size, epidermal cell number and initiation rate. Final leaf area was correlated to maximal absolute leaf expansion rate and cell number, but not to duration of leaf expansion or cell size. These relationships were common to all studied genotypes and light conditions, suggesting that leaf size is determined early in development. In addition, the early variables involved in leaf development were correlated to one another, and initial relative expansion rate was negatively correlated to the duration of expansion. These relationships between the leaf development variables were used to construct a conceptual model of leaf size control. [source]