Leaf area development of ABA-deficient and wild-type peas at two levels of nitrogen supply

2003 ◽  
Vol 30 (7) ◽  
pp. 777 ◽  
Author(s):  
Ian C. Dodd
Keyword(s):  
Growth Response ◽  
Leaf Growth ◽  
Nitrogen Supply ◽  
Genotypic Differences ◽  
Wild Type ◽  
Ethylene Evolution ◽  
Relative Water ◽  
Ca 50 ◽  
Area Development ◽  
Water Contents

The ABA-deficient wilty pea (Pisum sativum L.) and its wild-type (WT) were grown at two levels of nitrogen supply (0.5 and 5.0 mM) for 5–6 weeks from sowing, to determine whether leaf ABA status altered the leaf growth response to N deprivation. Plants were grown at high relative humidity to prevent wilting of the wilty peas. Irrespective of N supply, expanding wilty leaflets had ca 50% less ABA than WT leaflets but similar ethylene evolution rates. Fully expanded wilty leaflets had lower relative water contents (RWC) and were 10–60% smaller in area (according to the node of measurement) than WT leaflets. However, there were no genotypic differences in plant relative leaf expansion rate (RLER). Growth of both genotypes at 0.5 mM N increased the RWC of fully expanded leaflets, but did not alter ethylene evolution or ABA concentration of expanding leaflets. Plants grown at 0.5 mM N showed a 20–30% reduction in RLER, which was similar in magnitude in both wilty and WT peas. Thus,�leaf ABA status did not alter the leaf growth response to N deprivation.

Water stress affects the productivity, growth components, competitiveness and water relations of phalaris and white clover growing in a mixed pasture

1992 ◽  
Vol 43 (3) ◽  
pp. 659 ◽  
Author(s):  
L Guobin ◽  
DR Kemp ◽  
GB Liu
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
White Clover ◽  
Leaf Growth ◽  
Leaf Water ◽  
Water Potentials ◽  
Relative Water ◽  
Dry Conditions ◽  
Leaf Appearance ◽  
Water Contents

The effect of water stress during summer and recovery after rain on herbage accumulation, leaf growth components, stomatal conductance and leaf water relations of white clover (Trifolium repens cv. Haifa) and phalaris (Phalaris aquatica cv. Australian Commercial) was studied in an established mixed pasture under dryland (dry) or irrigated (wet) conditions. Soil water deficits under dry conditions reached 150 mm and soil water potentials in the top 20 cm declined to nearly -2 MPa after 50 days of dry weather. Water stress severely restricted growth of both species but then after rain fell, white clover growth rates exceeded those of phalaris. Under irrigation, white clover produced twice the herbage mass of phalaris but under dry conditions herbage production was similar from both species. Leaf appearance rates per tiller or stolon were slightly higher for white clover than phalaris but were reduced by 20% under water stress in both species. Leaf or petiole extension rates were more sensitive to water stress than leaf appearance rates and declined by 75% in phalaris and 90% in white clover. The ratio of leaf or petiole extension rates on dry/wet treatments was similar for both species in relation to leaf relative water contents, but in relation to leaf water potentials phalaris maintained higher leaf growth rates. Phalaris maintained a higher leaf relative water content in relation to leaf water potentials than did white clover and also maintained higher leaf water potentials in relation to the soil water potential in the top 20 cm. Stomata1 conductances for both species declined by 80-90% with increasing water stress, and both species showed similar stomatal responses to bulk leaf water potentials and leaf relative water contents. It is suggested that the poorer performance of white clover under water stress may be due principally to a shallower root system than phalaris and not due to any underlying major physiological differences. The white clover cultivar used in this study came from the mediterranean region and showed some different responses to water stress than previously published evidence on white clover. This suggests genetic variation in responses to water stress may exist within white clover. To maintain white clover in a pasture under dry conditions it is suggested that grazing practices aim to retain a high proportion of growing points.

scholarly journals Essential Function of the Pseudorabies Virus UL36 Gene Product Is Independent of Its Interaction with the UL37 Protein

2004 ◽  
Vol 78 (21) ◽  
pp. 11879-11889 ◽  
Author(s):  
Walter Fuchs ◽  
Barbara G. Klupp ◽  
Harald Granzow ◽  
Thomas C. Mettenleiter
Keyword(s):  
Gene Product ◽  
Pseudorabies Virus ◽  
Rabbit Kidney ◽  
Tegument Protein ◽  
Wild Type ◽  
Coding Region ◽  
Ordered Structures ◽  
Ca 50 ◽  
Essential Function ◽  
Full Length Clone

ABSTRACT The large tegument protein encoded by the UL36 gene of pseudorabies virus (PrV) physically interacts with the product of the adjacent UL37 gene (B. G. Klupp, W. Fuchs, H. Granzow, R. Nixdorf, and T. C. Mettenleiter, J. Virol. 76:3065-3071, 2002). To analyze UL36 function, two PrV recombinants were generated by mutagenesis of an infectious PrV full-length clone in Escherichia coli: PrV-ΔUL36F exhibited a deletion of virtually the complete UL36 coding region, whereas PrV-UL36BSF contained two in-frame deletions of 238 codons spanning the predicted UL37 binding domain. Coimmunoprecipitation experiments confirmed that the mutated gene product of PrV-UL36BSF did not interact with the UL37 protein. Like the previously described PrV-ΔUL37 (B. G. Klupp, H. Granzow, and T. C. Mettenleiter, J. Virol. 75:8927-8936, 2001) but in contrast to PrV-ΔUL36F, PrV-UL36BSF was able to replicate in rabbit kidney (RK13) cells, although maximum virus titers were reduced ca. 50-fold and plaque diameters were reduced by ca. 45% compared to wild-type PrV. PrV-ΔUL36F was able to productively replicate after repair of the deleted gene or in a trans-complementing cell line. Electron microscopy of infected RK13 cells revealed that PrV-UL36BSF and phenotypically complemented PrV-ΔUL36F were capable of nucleocapsid formation and egress from the nucleus by primary envelopment and deenvelopment at the nuclear membrane. However, reenvelopment of nucleocapsids in the cytoplasm was blocked. Only virus-like particles without capsids were released efficiently from cells. Interestingly, cytoplasmic nucleocapsids of PrV-UL36BSF but not of PrV-ΔUL36F were found in large ordered structures similar to those which had previously been observed with PrV-ΔUL37. In summary, our results demonstrate that the interaction between the UL36 and UL37 proteins is important but not strictly essential for the formation of secondary enveloped, infectious PrV particles. Furthermore, UL36 possesses an essential function during virus replication which is independent of its ability to bind the UL37 protein.

Do low-ethylene-producing transgenic canola (Brassica napus) plants expressing the ACC deaminase gene differ from wild-type plants in response to UVB radiation?

2007 ◽  
Vol 85 (2) ◽  
pp. 148-159 ◽  
Author(s):  
Mirwais M. Qaderi ◽  
M. Anisul Islam ◽  
David M. Reid ◽  
Saleh Shah
Keyword(s):  
Brassica Napus ◽  
Transgenic Plants ◽  
Photosynthetic Pigment ◽  
Physiological Parameters ◽  
Ultraviolet B ◽  
Differential Sensitivity ◽  
Plant Responses ◽  
Uvb Radiation ◽  
Wild Type ◽  
Ethylene Evolution

Few studies have considered ethylene involvement in plant responses to ultraviolet-B (UVB) radiation. We studied the responses to UVB radiation of one wild-type (WT, ‘Westar’) canola (Brassica napus L.) with normal ethylene evolution and two transgenic (C1, C2) lines with lower ethylene evolution. Canola plants were grown under biologically effective levels of UVB (UVBBE) radiation: 0.03 (low), 4.88 (medium), and 9.78 (high) kJ·m–2·d–1 in controlled-environment growth chambers. The growth and physiological parameters of the plants were measured. Of the two transgenic lines, C1 demonstrated higher ethylene evolution than C2 but lower than WT. The lowest aboveground and belowground biomass was found with exposure to high UVB radiation. WT produced more biomass than C2. Net CO2 assimilation and transpiration did not vary among plant lines or UVB treatments. Water-use efficiency was lower under high UVB radiation than under low UVB. The quantum yield of photosystem II was higher for C2 than for either WT or C1. WT did not differ from transgenic plants in respect to photosynthetic pigments and UV-screening compounds. Photosynthetic pigment concentration decreased, but concentration of UV-screening compounds, thickness of epicuticular wax, and the rate of root hydraulic conductance were increased by exposure to UVB radiation. While there appears to be a lack of ethylene involvement in some of the measured physiological parameters, the transgenic plants exhibited differential sensitivity to UVB in a few key measured parameters.

Studies in citrus nutrition i. Leaf growth and composition

1956 ◽  
Vol 7 (4) ◽  
pp. 248 ◽  
Author(s):  
RF Williams ◽  
CT Gates
Keyword(s):  
Organic Matter ◽  
Treatment Effects ◽  
Nitrogen Nutrition ◽  
Leaf Growth ◽  
Dry Weight ◽  
Nitrogen Supply ◽  
Dominant Factor ◽  
Nitrogen And Phosphorus ◽  
Citrus Grove ◽  
Four Levels

Vegetative shoots from the spring flush of an experimental citrus grove tagged and sampled on three occasions at intervals of 6 months. The effects of four cultural treatments, four levels of nitrogen supply, four combinations of stock and scion, and of time on leaf area and dry weight, and on relative and absolute contents of water, nitrogen, and phosphorus are presented and discussed. While nitrogen nutrition is still the dominant factor, the evidence strongly suggests that phosphorus nutrition has become important as a determinant of treatment effects within the experimental grove. The possible relevance of soil temperature and soil organic matter for some of the cultural treatment effects is discussed.

Visual assessment of total plant relative water content, with the aid of photographic standards, as a guide to scheduling irrigation

1974 ◽  
Vol 14 (66) ◽  
pp. 76
Author(s):  
GJ Luke
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Visual Assessment ◽  
Whole Plant ◽  
Accurate Indication ◽  
Relative Water ◽  
Total Plant ◽  
Scheduling Irrigation ◽  
Maize Plants ◽  
Water Contents

The relative water contents (RWC) of the top and bottom leaves of maize plants were measured. The RWC of the top leaf was higher than that of the bottom leaf when the plant was under water stress. Photographic standards based on the RWC of the whole plant were developed and tested against plants in the field. The results showed that the standards give an accurate indication of the plant's water status. Standards based on the upper leaf only would result in irrigations too infrequent to prevent severe restrictions to photosynthesis.

Water Stressed Nodal Roots of Wheat: Effects on Leaf Growth

1997 ◽  
Vol 24 (1) ◽  
pp. 49 ◽  
Author(s):  
K. M. Volkmar
Keyword(s):  
Growth Rate ◽  
Water Content ◽  
Relative Water Content ◽  
Leaf Growth ◽  
Seminal Root ◽  
Nodal Roots ◽  
Nodal Root ◽  
Relative Water ◽  
Seminal Roots ◽  
Leaf Relative Water Content

This experiment as undertaken to determine the efects of soil drying around the nodal and/or seminal root systems on the shoot growth of wheat (Triticum aestivum L.). Two split-root experiments were conducted, the first on newly emerged nodal roots of 18-day-old wheat plants, the second on 25-day-old plants. In both experiments, nodal and seminal roots were isolated from one another and water was withheld from either the nodal root chamber, the seminal root chamber, or both, over 6 days. In the first experiment, leaf growth was unaffected by withholding water from very short nodal roots, even though leaf relative water content of the droughted plants decreased. By comparison, both leaf elongation rate and relative water content decreased by withholding water from the seminal roots. On plants that were 1 week older, leaf growth rate and leaf relative water content decreased when nodal roots were drought-stressed. Leaf growth rate of seminal root droughted plants was more impaired than their nodal root counterparts, even though leaf relative water contents of the two treatments were the same. In both experiments, drought stress applied to the nodal root system enhanced nodal root growth more than seminal roots. These results suggest that seminal and nodal roots perceive and respond to drought stress differently with respect to the nature of the message conveyed to the shoots.

Leaf growth and K+/Na+ ratio as an indication of the salt tolerance of three sorghum cultivars grown under salinity stress and IAA treatment

2004 ◽  
Vol 52 (3) ◽  
pp. 287-296 ◽  
Author(s):  
M. M. Azooz ◽  
M. A. Shaddad ◽  
A. A. Abdel-Latef
Keyword(s):  
Salt Tolerance ◽  
Water Content ◽  
Leaf Area ◽  
Salinity Stress ◽  
Relative Water Content ◽  
Leaf Growth ◽  
Dry Mass ◽  
Inhibitory Effect ◽  
Tolerance Index ◽  
Relative Water

The salt tolerance of three sorghum (Sorghum bicolor L.) cultivars (Dorado, Hagen Shandawil and Giza 113) and their responses to shoot spraying with 25 ppm IAA were studied. Salinity stress induced substantial differences between the three sorghum cultivars in the leaf area, dry mass, relative water content and tolerance index of the leaves. Dorado and Hagen Shandawil tolerated salinity up to 88 and 44 mM NaCl, respectively, but above this level, and at all salinity levels in Giza 113, a significant reduction in these parameters was recorded. The rate of reduction was lower in Dorado than in Hagen Shandawil and Giza 113, allowing the sequence Dorado ? Hagen Shandawil ? Giza 113 to be established for the tolerance of these cultivars to salinity. The differences in the tolerance of the sorghum cultivars were associated with large differences in K+ rather than in Na+, which was found to be similar in the whole plant. The youngest leaf was able to maintain a higher K+ content than the oldest leaf. Consequently the K+/Na+ ratios were higher in the most salt-tolerant cultivar Dorado than in the other sorghum cultivars, and in the youngest than in the oldest leaf. In conformity with this mechanism, the stimulatory effect of the exogenous application of IAA was mostly associated with a higher K+/Na+ ratio. Shoot spraying with IAA partially alleviated the inhibitory effect of salinity on leaf growth and on the K+ and Ca2+ contents, especially at low and moderate levels of salinity, while it markedly retarded the accumulation of Na+ in the different organs of sorghum cultivars. Abbreviations: LA: Leaf area, DM: Dry mass, I Indole acetic acid, RWC: Relative water content,TI: Tolerance index

scholarly journals Drought Induces Distinct Growth Response, Protection, and Recovery Mechanisms in the Maize Leaf Growth Zone

2015 ◽  
Vol 169 (2) ◽  
pp. 1382-1396 ◽  
Author(s):  
Viktoriya Avramova ◽  
Hamada AbdElgawad ◽  
Zhengfeng Zhang ◽  
Bartosz Fotschki ◽  
Romina Casadevall ◽  
...  
Keyword(s):  
Growth Response ◽  
Leaf Growth ◽  
Growth Zone ◽  
Maize Leaf ◽  
Recovery Mechanisms

scholarly journals Measurement of leaf lamina moisture with a low-cost electrical humidity sensor: case study on a wheat water-mutant

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Agata Rascio ◽  
Michele Rinaldi ◽  
Giuditta De Santis ◽  
Nicola Pecchioni ◽  
Gabriele Palazzo ◽  
...  
Keyword(s):  
Moisture Content ◽  
Electrical Resistance ◽  
Low Cost ◽  
Bound Water ◽  
Genotypic Differences ◽  
Wild Type ◽  
Leaf Lamina ◽  
Mature Leaves ◽  
Moisture Meter

Abstract Background The presence and persistence of water on the leaf can affect crop performance and thus might be a relevant trait to select for or against in breeding programmes. Low-cost, rapid and relatively simple methods are of significant importance for screening of large populations of plants for moisture analysis of detached leaves. Leaf moisture can be detected using an electric circuit, where the resistance changes are proportional to the moisture of the measured surface. In this study, we present a protocol to analyse genotypic differences through the electrical properties of living or stored tissues, performed using a commercial device. Expanded and non-expanded leaves were compared to determine the effects of leaf maturity on these data. Two wheat genotypes that differ in tissue affinity for bound water were used to define the influence of water status. Results The device indirectly estimates leaf moisture content using two electrodes applied to the leaf lamina of fresh and stored samples. Single moisture readings using this moisture meter had mean execution time of ~ 1.0 min. Exponential associations provided good fits for relationships between the moisture meter reading (MMR) and the electrical resistance applied to the electrodes. MMR normalised for the water/ dry matter ratio (MMRnorm) was lower for mature leaves of the water-mutant than those of wild-type, for the fully hydrated fresh leaves. MMR of fully mature leaves when partially dehydrated and measured after 10 min at 27 °C and 40% relative humidity was greater for the water-mutant than the wild-type. Conclusions This case study provides a low-cost tool to compare electrical-resistance estimates of leaf moisture content, together with a promising and rapid phenotyping protocol for genotypic screening of wheat under standard environmental conditions. Measurement of changes in MMR with time, of fresh and partially dehydrated leaves, or of MMR normalised to tissue water content allowed for differentiation between the genotypes. Furthermore, the differences observed between genotypes that here relate particular to tissue affinity for bound water suggest that not only the free-water fraction, but also other water fractions, can affect these electrically estimated leaf moisture measures.

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