scholarly journals SALINITY STRESS RESPONSES OF MINIATURE DWARF TOMATO IN A WHOLE PLANT MICROCULTURE EVALUATION SYSTEM

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1149c-1149
Author(s):  
M. A. L. Smith ◽  
S. L. Knight ◽  
M. J. Bass
Keyword(s):  
Root Growth ◽  
Stress Responses ◽  
Evaluation System ◽  
Time Course ◽  
Shoot Growth ◽  
Root Growth Inhibition ◽  
Plant Responses ◽  
Tissue Quality ◽  
Osmotic Concentration ◽  
Whole Plant

A whole plant microculture (WPMC) screening system facilitated rapid, quantitative appraisal of salt stress effects on `Micro-Tom' miniature dwarf tomato. Axillary bud explants were micropropagated on a hormone-free control medium (conductivity = 3.3 dS m-1), gradually introduced to treatments with increasing NaCl or Na2SO4 concentrations via biweekly subculture to fresh media (7,6, 12.8, or 18 dS m-1), and monitored over a subsequent 5 week culture period. Non-intrusive video image analysis techniques were adapted to quantify morphometric (shoot growth rate, area, and length; root length and area) and photometric (ruler and tissue quality) plant responses. Shoot growth was only slightly inhibited at 7.6 and 12.8 dS m-1, but was severely stunted and distorted on high salt (18 dS m-1) media. Root growth inhibition (significantly shorter and thinner primary rants) was first evident at 12.8 dS m-1 after 3 weeks of treatment. At 18 dS m-1, conspicuous retardation of root growth relative to controls could be gauged after only one week. Shoot tip chlorosis was observed in the lowest salt-supplemented treatment after three to four weeks of culture, but overall shoot yellowing at the two highest conductivities was marked after only a few days. Chlorosis symptoms were not uniform within treatments. Cell osmotic concentration showed a linear increase with increasing medium salinity. The WPMC system expedited time course observations of stress symptom development, paralleled stress response trends observed in solution culture tests, and provided an excellent vehicle to investigate plant adaptation to saline conditions.

scholarly journals Root Growth of Avocado is More Sensitive to Salinity than Shoot Growth

2004 ◽  
Vol 129 (2) ◽  
pp. 188-192 ◽  
Author(s):  
N. Bernstein ◽  
A. Meiri ◽  
M. Zilberstaine
Keyword(s):  
Salt Stress ◽  
Root Growth ◽  
Biomass Production ◽  
Root Elongation ◽  
Shoot Growth ◽  
Elongation Rate ◽  
Persea Americana ◽  
Root Growth Inhibition ◽  
Leaf Biomass ◽  
Volumetric Growth

In most crop species, growth of the shoot is more sensitive to salt stress than root growth. Avocado [Persea americana Mill.] is very sensitive to NaCl stress. Even low concentrations of salt (15 mm) inhibit tree growth and decrease productivity. Observations in experimental orchards have suggested that root growth in avocado might be more restricted by salinity than shoot growth. In the present study, we evaluated quantitatively the inhibitory effects of salt stress on growth of the avocado root in comparison to the shoot. Seedling plants of the West-Indian rootstock `Degania 117' were grown in complete nutrient solution containing 1, 5, 15, or 25 mm NaCl. The threshold NaCl concentration causing root and shoot growth reduction occurred between 5 and 15 mm. At all concentrations, root growth was much more sensitive to salinity than shoot growth. A concentration of 15 mm NaCl, which did not affect the rate of leaf emergence on the plant and decreased leaf biomass production only 10%, induced a 43% reduction in the rate of root elongation and decreased root volumetric growth rate by 33%. Under 25 mm NaCl, leaf biomass production, leaf initiation rate and leaf elongation rate were reduced 19.5%, 12%, and 5%, respectively, while root volumetric growth and root elongation rate were reduced 65% and 75%, respectively. This strong root growth inhibition is expected to influence the whole plant and therefore root growth under salinity should be considered as an important criterion for rootstocks' tolerance to NaCl.

scholarly journals Underground Azelaic Acid–Conferred Resistance to Pseudomonas syringae in Arabidopsis

2019 ◽  
Vol 32 (1) ◽  
pp. 86-94 ◽  
Author(s):  
Nicolás M. Cecchini ◽  
Suruchi Roychoudhry ◽  
DeQuantarius J. Speed ◽  
Kevin Steffes ◽  
Arjun Tambe ◽  
...  
Keyword(s):  
Root Growth ◽  
Pseudomonas Syringae ◽  
Azelaic Acid ◽  
Plant Immunity ◽  
Root Growth Inhibition ◽  
Individual Plant ◽  
Lipid Transfer ◽  
Systemic Immunity ◽  
Whole Plant

Local interactions between individual plant organs and diverse microorganisms can lead to whole plant immunity via the mobilization of defense signals. One such signal is the plastid lipid-derived oxylipin azelaic acid (AZA). Arabidopsis lacking AZI1 or EARLI1, related lipid transfer family proteins, exhibit reduced AZA transport among leaves and cannot mount systemic immunity. AZA has been detected in roots as well as leaves. Therefore, the present study addresses the effects on plants of AZA application to roots. AZA but not the structurally related suberic acid inhibits root growth when directly in contact with roots. Treatment of roots with AZA also induces resistance to Pseudomonas syringae in aerial tissues. These effects of AZA on root growth and disease resistance depend, at least partially, on AZI1 and EARLI1. AZI1 in roots localizes to plastids, similar to its known location in leaves. Interestingly, kinases previously shown to modify AZI1 in vitro, MPK3 and MPK6, are also needed for AZA-induced root-growth inhibition and aboveground immunity. Finally, deuterium-labeled AZA applied to the roots does not move to aerial tissues. Thus, AZA application to roots triggers systemic immunity through an AZI1/EARLI1/MPK3/MPK6-dependent pathway and AZA effects may involve one or more additional mobile signals.

Whole plant response of crop and weed species to high subsoil boron

2006 ◽  
Vol 57 (7) ◽  
pp. 761 ◽  
Author(s):  
Eun-Young Choi ◽  
Ann McNeill ◽  
David Coventry ◽  
James Stangoulis
Keyword(s):  
Root Growth ◽  
Water Use ◽  
Direct Relationship ◽  
Shoot Growth ◽  
Dry Weight ◽  
Total Water ◽  
Weed Species ◽  
Evening Primrose ◽  
Whole Plant ◽  
Prickly Lettuce

Within the semi-arid region of south-eastern Australia, high levels of subsoil boron (B) in alkaline soil can limit production of dryland crops. The aim of this research was to investigate the whole plant response to a range of subsoil-extractable B concentrations for a number of crop and weed species common to agricultural areas of South Australia. Specifically, the objectives were to determine (a) the morphological response of the entire root system to high subsoil B and (b) the available B concentrations in subsoil critical for expression of shoot traits commonly used in selection of B tolerance. Barley grass (Hordeum glaucum L.), crop barley (Hordeum vulgare) variety Clipper and breeders’ line VB9953, fababean (Vicia faba var. Fjiord), Lincoln weed (Diplotaxis tenuifolia L.), prickly lettuce (Lactuca serriola), and evening primrose (Oenothera stricta L.) were grown in sealed PVC cylinders (500 mm deep by 150 mm diam.) containing a sandy soil. The concentration of extractable B in the topsoil (0–0.20 m), considered non-toxic, was 0.5 mg/kg for all cylinders but a range of B treatments (0.5, 2.4, 4.3, 6.8, or 12.2 mg/kg) was applied directly to the subsoil (0.30–0.50 m). Increasing the concentration of extractable B in the subsoil decreased root dry weight in this region, but did not reduce water use from subsoil by barley grass or evening primrose. The response of the roots in the topsoil and subsequent responses in the shoot also differed among species. Symptoms of B toxicity in shoots of all the species were observed at subsoil-extractable B concentrations of 12.2 mg/kg and at lower concentrations in some of the crop and weed species. Shoot growth, total water use, and root growth in topsoil of Clipper and Lincoln weed were severely impaired by high subsoil-extractable B, as was topsoil root growth in evening primrose, with the reduction in the weed species being mostly associated with a decrease in taproot dry weight. Barley grass, VB9953, evening primrose, and to a lesser extent fababean and prickly lettuce, maintained shoot growth at all subsoil-extractable B concentrations, despite a reduction in subsoil water use by VB9953. Prickly lettuce and VB9953 also sustained root growth in the topsoil whilst fababean and barley grass increased root growth in the topsoil in response to high subsoil extractable B. There was no direct relationship between the quantity of B accumulated in shoots and detrimental effects on growth. Furthermore, there appeared to be no direct relationship between water uptake and B uptake since irrespective of the effect of subsoil B on either subsoil or total water use, shoot B concentration increased in all the species/genotypes as subsoil B increased. The degree to which plants were deemed to exhibit tolerance was, therefore, highly dependent upon the trait used for assessment. One suggestion in the current study is that shoot dry matter in B toxic soil can be a consistent parameter for considering varieties for tolerance to B toxicity.

Whole-Plant Responses to Salinity

1986 ◽  
Vol 13 (1) ◽  
pp. 143 ◽  
Author(s):  
R Munns ◽  
A Termaat
Keyword(s):  
Root Growth ◽  
Leaf Growth ◽  
Water Status ◽  
Leaf Expansion ◽  
Saline Soils ◽  
Plant Responses ◽  
Short Term ◽  
Whole Plant ◽  
Short Term Exposure

This paper discusses whole-plant responses to salinity in order to answer the question of what process limits growth of non-halophytes in saline soils. Leaf growth is more sensitive to salinity than root growth, so we focus on the process or processes that might limit leaf expansion. Effects of short-term exposure (days) are considered separately from long-term exposure (weeks to years). The answer in the short term is probably the water status of the root and we suggest that a message from the root is regulating leaf expansion. The answer to what limits growth in the long term may be the maximum salt concentration tolerated by the fully expanded leaves of the shoot; if the rate of leaf death approaches the rate of new leaf expansion, the photosynthetic area will eventually become too low to support continued growth.

scholarly journals Effects of green seaweed extract on Arabidopsis early development suggest roles for hormone signalling in plant responses to algal fertilisers

2018 ◽  
Author(s):  
Fatemeh Ghaderiardakani ◽  
Ellen Collas ◽  
Deborah Kohn Damiano ◽  
Katherine Tagg ◽  
Neil S. Graham ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Growth Inhibition ◽  
Early Development ◽  
Land Plant ◽  
Root Growth Inhibition ◽  
Plant Responses ◽  
Germination Inhibition ◽  
Green Seaweed ◽  
Algal Extracts

AbstractThe growing population requires sustainable, environmentally-friendly crops. The plant growth-enhancing properties of algal extracts have suggested their use as biofertilisers. The mechanism(s) by which algal extracts affect plant growth are unknown.We examined the effects of extracts from the common green seaweed Ulva intestinalis on germination and root development in the model land plant Arabidopsis thaliana. Ulva extract concentrations above 0.1% inhibited Arabidopsis germination and root growth. Ulva extract <0.1% stimulated root growth. All concentrations of Ulva extract inhibited lateral root formation. An abscisic-acid-insensitive mutant, abi1, showed altered sensitivity to germination- and root growth-inhibition inhibition. Ethylene- and cytokinin-insensitive mutants were partly insensitive to germination-inhibition. This suggests that different mechanisms mediate each effect of Ulva extract on early Arabidopsis development and that multiple hormones contribute to germination-inhibition.Elemental analysis showed that Ulva contains high levels of Aluminium ions (Al3+). Ethylene and cytokinin have been suggested to function in Al3+-mediated root growth inhibition: our data suggest that if Ulva Al3+ levels inhibit root growth, this is via a novel mechanism. We suggest algal extracts should be used cautiously as fertilisers, as the inhibitory effects on early development may outweigh any benefits if the concentration of extract is too high.

scholarly journals EFFECTS OF BROCCOLI-CROPPED SOIL ON THE GROWTH OF BROCCOLI, CABBAGE, AND CAULIFLOWER

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 268A-268
Author(s):  
Jose Reynaldo A. Santos ◽  
Daniel I. Leskovar
Keyword(s):  
Root Growth ◽  
Leaf Area ◽  
Shoot Growth ◽  
Leaf Color ◽  
Stunted Growth ◽  
Whole Plant ◽  
Leaf Chlorosis ◽  
Root And Shoot Growth ◽  
Percent Germination ◽  
Over Time

Broccoli, cabbage, and cauliflower were grown in the greenhouse on fallowed soil (FS) or on soil previously cropped with broccoli CBS) for three years. Fertilization levels (kg/ha) were none, 67N-22P, and 135N-44P. Inhibition of root and shoot growth components, and leaf color was evaluated at 30, 44, 58, and 72 days after seeding. Shoot and root growth of cauliflower, grown on BS, progressively declined over time, while that of broccoli and cabbage either increased or remained unaffected. Application of fertilizer (67N-22P) improved the shoot growth of cabbage but did not alleviate the symptoms associated with allelopathy, i.e., stunted growth, leaf chlorosis, reduced leaf area, observed in cauliflower. Whole plant extract of broccoli decreased percent germination of cauliflower, and reduced the speed of germination of all three test crops in the order of cauliflower>broccoli>cabbage.

Melatonin alleviates aluminium toxicity through modulating antioxidative enzymes and enhancing organic acid anion exudation in soybean

2017 ◽  
Vol 44 (10) ◽  
pp. 961 ◽  
Author(s):  
Jiarong Zhang ◽  
Bingjie Zeng ◽  
Yawen Mao ◽  
Xiangying Kong ◽  
Xinxun Wang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Critical Role ◽  
Aluminium Toxicity ◽  
Al Toxicity ◽  
Root Growth Inhibition ◽  
H2o2 Production ◽  
Plant Responses ◽  
Al Stress ◽  
High Concentrations

Aluminium (Al) toxicity is a major chemical constraint limiting plant growth and production on acidic soils. Melatonin (N-acetyl-5-methoxytryptamine) is a ubiquitous molecule that plays crucial roles in plant growth and stress tolerance. However, there is no knowledge regarding whether melatonin is involved in plant responses to Al stress. Here, we show that optimal concentrations of melatonin could effectively ameliorate Al-induced phytotoxicity in soybean (Glycine max L.). The concentration of melatonin in roots was significantly increased by the 50 μM Al treatment. Such an increase in endogenous melatonin coincided with the upregulation of the gene encoding acetyltransferase NSI-like (nuclear shuttle protein-interacting) in soybean roots. Supplementation with low concentrations of melatonin (0.1 and 1 μM) conferred Al resistance as evident in partial alleviation of root growth inhibition and decreased H2O2 production: in contrast, high concentrations of melatonin (100 and 200 μM) had an opposite effect and even decreased root growth in Al-exposed seedlings. Mitigation of Al stress by the 1 μM melatonin root treatment was associated with enhanced activities of the antioxidant enzymes and increased exudation of malate and citrate. In conclusion, melatonin might play a critical role in soybean resistance to Al toxicity.

scholarly journals Strategies to Apply Water-Deficit Stress: Similarities and Disparities at the Whole Plant Metabolism Level in Medicago truncatula

2021 ◽  
Vol 22 (6) ◽  
pp. 2813
Author(s):  
Verónica Castañeda ◽  
Esther M. González
Keyword(s):  
Drought Stress ◽  
Water Deficit ◽  
Stress Responses ◽  
Carbon Metabolism ◽  
Crop Productivity ◽  
Invertase Activity ◽  
Water Deficit Stress ◽  
Plant Responses ◽  
Whole Plant ◽  
Plant Level

Water-deficit stresses such as drought and salinity are the most important factors limiting crop productivity. Hence, understanding the plant responses to these stresses is key for the improvement of their tolerance and yield. In this study M. truncatula plants were subjected to 250 mM NaCl as well as reduced irrigation (No-W) and 250 g/L polyethylene glycol (PEG)-6000 to induce salinity and drought stress, respectively, provoking a drop to −1.7 MPa in leaf water potential. The whole plant physiology and metabolism was explored by characterizing the stress responses at root, phloem sap and leaf organ level. PEG treatment led to some typical responses of plants to drought stress, but in addition to PEG uptake, an important impairment of nutrient uptake and a different regulation of carbon metabolism could be observed compared to No-W plants. No-W plants showed an important redistribution of antioxidants and assimilates to the root tissue, with a distinctive increase in root proline degradation and alkaline invertase activity. On the contrary, salinity provoked an increase in leaf starch and isocitrate dehydrogenase activity, suggesting key roles in the plant response to this stress. Overall, results suggest higher protection of salt-stressed shoots and non-irrigated roots through different mechanisms, including the regulation of proline and carbon metabolism, while discarding PEG as safe mimicker of drought. This raises the need to understand the effect at the whole plant level of the different strategies employed to apply water-deficit stress.

scholarly journals Response to Phosphorus Availability during Vegetative and Reproductive Growth of Chrysanthemum: II. Biomass and Phosphorus Dynamics

1998 ◽  
Vol 123 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Conny W. Hansen ◽  
Jonathan Lynch
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Production Rate ◽  
Root Length ◽  
Shoot Growth ◽  
Biomass Accumulation ◽  
Shoot Biomass ◽  
Reproductive Growth ◽  
Relative Growth ◽  
Whole Plant

Whole-plant biomass accumulation, P dynamics, and root-shoot interactions during transition from vegetative to reproductive growth of `Coral Charm' chrysanthemum (Dendranthema ×grandiflorum Ramat.) (Zander, 1993) were investigated over a range of P concentrations considered to be deficient (1 μm), adequate (100 μm), and high (5 mm). In nondeficient plants, transition from vegetative to reproductive growth resulted in reduced relative growth rate and root and shoot biomass accumulation. Reproductive plants showed a higher commitment of the whole plant to the production of developing flowers than to leaves and roots, whereas, in vegetative plants, the highest component production rate was in leaves. This indicates changes in the source-sink relationships during transition from vegetative growth making developing flowers stronger sinks for photoassimilates than roots. Phosphorus allocated to developing flowers was predominantly lost from leaves. Phosphorus-deficient plants showed characteristic P-deficiency symptoms and favored root growth over shoot growth regardless of growth stage. Phosphorus availability in nondeficient plants affected root growth more than shoot growth. No substantial differences in shoot biomass production, relative growth rate, and CO2 assimilation rates were observed in adequate-P and high-P plants. However, the root component production rate, root to shoot ratio, root length ratio, specific root length, specific root area, root mass to leaf area ratio, and root respiration increased in adequate-P plants compared with high-P plants, which indicates that high root activity was maintained without affecting shoot biomass in buffered P conditions. Our results suggest that the high P concentrations used in many horticultural systems may have no benefit in terms of shoot growth and may actually be detrimental to root growth.

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