scholarly journals Possible role of growth regulators in adaptation to heat stress affecting partitioning of photosynthates in tomato plants

2014 ◽  
Vol 58 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Zofia Starck ◽  
Elżbieta Cieśla
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Growth Regulators ◽  
Specific Activity ◽  
Invertase Activity ◽  
Acid Invertase ◽  
Sink Strength ◽  
Tomato Plants ◽  
Different Response

Tomato plants of two cultivars: Roma - sensitive and Robin - tolerant to heat stress were grown in greenhouse up to the flowering stage and then under controlled environmen­tal conditions. The partitioning of recently fixed <sup>14</sup>CO<sub>2</sub> by mature tomato leaves was examined as a posteffect of 24-h heat stress (38/25°C day/night) with the interaction of growth regulators (GR) sprayed on the flowers with solution of β-naphthoxyacetic (NOA) and gibberellic (GA<sub>3</sub>) acid (denoted as NG), or Zeatin + NOA + GA<sub>3</sub> (denoted as ZNG). In both cuitivars GR strongly stimulated fruit growth and transport of <sup>14</sup>C-photosynthates to the clusters at the expense of vegetative organs. Heat stress decreased export of <sup>14</sup>C-phoiosynthates from the blades in plants not treated with GR, but even more in cv. Roma. In Roma plants not treated with GR (with very small fruitlets and fruits) the heat stress retarded <sup>14</sup>C-transport just in the petioles, diminishing the <sup>14</sup>C-supply to the fruits. Reduction of the current photosynthate supplied to the fruits seems to be causally connected with inhibition of the specific activity of acid invertase in that organ. Growth regulators reduced the negative effect of high temperature - they alleviated depression of <sup>14</sup>C-export from the blades and increased invertase activity. <sup>14</sup>C-photosynthate transport to the fruits, presumably owing to their higher sink strength, was less affected by heat stress. In Robin plants (which had bigger fruits during the experiment) high temperature depressed <sup>14</sup>C-fruit supply only in the NG-series, in contrast to enhacement of <sup>14</sup>C-Movement to that sink in the control and ZNG-series. In spite of these facts, after heat stress, the specific activity of acid invertase decreased in all the experimental series, but much less in the GR-treated series. Therefore, in the Robin cv. there was no relation between invertase activity and <sup>14</sup>C-mobilization by fruits, as was observed in Roma plants. The possible explanation of the different response of the two cultivars with contrasting sensitivity to heat stress; with special reference to the role of GR; diminishing injury of the plants by high temperature is discussed.

scholarly journals Diverse response of tomato fruit explants to high temperature

2014 ◽  
Vol 62 (3-4) ◽  
pp. 165-169 ◽  
Author(s):  
Zofia Starck ◽  
Barbara Witek-Czupryńska
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Elevated Temperature ◽  
Specific Activity ◽  
Tomato Fruit ◽  
Calcium Content ◽  
Invertase Activity ◽  
Acid Invertase ◽  
Sucrose Uptake ◽  
Soluble Acid Invertase

Tomato explants (fruit with a pedicel and a piece of peduncle), with fruit growth stimulated by treating the flowers with NOA + GA&lt;sub&gt;3&lt;/sub&gt; (NG-series) were used as a model system for studying the effect of high temperature on C-sucrose uptake, its distribution and Ca retranslocation. Two cultivars with contrasting responses to high temperature were compared. In sensitive cv. Roma heat stress during 22h (40&lt;sup&gt;o&lt;/sup&gt;C for 10h and 30&lt;sup&gt;o&lt;/sup&gt;C for 12h), drastically depressed the uptake of <sup>14</sup>C-sucrose coinciding with diminished fruit <sup>14</sup>C-supply. It also decreased the specific activity of soluble acid invertase and the calcium content. All these strong negative responses to high temperature were markedly reduced in the NG-treated series involving remobilization of Ca to the fruits and a higher stability of the invertase activity. This indicates the indirect role of flower treatment with NG in addaptation to heat stress. In tolerant cv. Robin even higher temperatures (42&lt;sup&gt;o&lt;/sup&gt;C for 10h and 34&lt;sup&gt;o&lt;/sup&gt;C for 12h) were not stressful. They did not affect the <sup>14</sup>C-sucrose uptake and stimulated <sup>14</sup>C-supply to the fruit. Increased specific activity of acid invertase and a higher calcium content were also recorded but only in the control explants. In contrast to cv. Roma elevated temperature was slightly stressful for cv. Robin explants of NG-series. The differences in response of both cultivar explants to elevated temperature, based on unequal fruit supply with <sup>14</sup>C-sucrose, seem to be causaly connected with two factors: the invertase activity being more or less sensitive to the heat stress, the ability to translocate Ca to the heated fruits.

scholarly journals Possible role of growth regulators in adaptation to heat stress affecting partitioning of photosynthates in tomato plants

2014 ◽  
Vol 58 (1) ◽  
pp. 85-95
Author(s):  
Kazimierz Zalewski
Keyword(s):  
Heat Stress ◽  
Dehydrogenase Activity ◽  
Growth Regulators ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Tomato Plants ◽  
Lower Ability ◽  
Adaptation To Heat

The formation of polyribosomes and total dehydrogenase activity in rye grains from different harvest years (with different viability) were studied. It was found using actinomycin D and cordycepin that grain aging was related to a lower ability for RNA synthesis and polyribosome formation. At least part of the stored form of RNA (preformed mRNA) in the embryos of both aged non-viable grain was able to form complexes with ribosomes.

Role of vacuoles and vesicles in extracellular enzyme secretion from yeast

1973 ◽  
Vol 19 (1) ◽  
pp. 113-117 ◽  
Author(s):  
R. A. Holley ◽  
D. K. Kidby
Keyword(s):  
Specific Activity ◽  
High Specific Activity ◽  
Extracellular Enzyme ◽  
Invertase Activity ◽  
Preliminary Evidence ◽  
Acid Protease ◽  
Intracellular Enzyme ◽  
Per Se ◽  
Equilibrium Centrifugation

Preliminary evidence has been obtained which suggests that the intracellular invertase of Saccharomyces cerevisiae may not be localized in the vacuole per se. Alkaline phosphatase, an intracellular enzyme, and acid protease, a typically lysosomal enzyme, both showed high specific activity in the vacuole fraction prepared by equilibrium centrifugation of lysed sphaeroplasts in Ficoll gradients. Invertase activity has been found to be associated with vacuoles only when glucose-repressed cells are derepressed. Cells derepressed for invertase biosynthesis contained a population of vesicles which were virtually absent from the repressed cells. Evidence is presented which strongly suggests that these vesicles rather than the vacuoles are the vehicle by which invertase is secreted from the cell.

scholarly journals Role of salicylic acid in heat stress tolerance in tri-genomic Brassica napus L.

2020 ◽  
Vol 33 (1) ◽  
pp. 13-20
Author(s):  
Muhammad Awais Ghani ◽  
Muhammad Mehran Abbas ◽  
Basharat Ali ◽  
Khurram Ziaf ◽  
Muhammad Azam ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Heat Stress ◽  
High Temperature ◽  
Brassica Napus ◽  
Biochemical Analysis ◽  
Foliar Application ◽  
Brassica Napus L ◽  
Elevated Activity ◽  
Heat Stress Tolerance

Tri-genomic Brassica napus L.wasdeveloped by the cross between Brassica napusand Brassica nigra. The crop is animportant source of vegetable seed oil in Pakistan,after cotton. The low oilseed rape yield is attributed to high temperature in the production zones. Interspecific hybridization using these two speciescan be helpful to produce heat resistant hybrids. On the other hand, it has been found that foliar application of different plant growth regulators can be used to reduce the heat stress in Brassica. The objectiveof this studywas to test the response of three different tri-genomic hybrids to high temperature stressat seedling stage. Seedlings were foliar sprayed with 0.13 mM salicylic acid (SA) prior to exposure tohigh temperatureat two true leaf stage. The plants were harvested after 30 days of sowing for growth and biochemical analysis. Plants ofV38 showed the highest values for all morphological traits and biochemical activities among the threehybrids. In general, plants exposed to the temperature stress exhibited a significant decline in growth, chlorophyll content and enzyme activity.Foliar application of SA significantly improved leaf and root biomass under heat stress.Further, antioxidativeenzyme activities significantly increased in response to SA either compared to control or to plants exposed to temperature stress.It is concluded thatapplication of salicylic acid elevated activity of antioxidative enzymes and was helpful in mitigating the detrimental effects of high temperature inoil seed rape.

Effect of Aloin on the Soluble Sugars Metabolism and Flavor Quality Keeping of Gonggan

2011 ◽  
Vol 140 ◽  
pp. 309-313
Author(s):  
Jian Liang Liu ◽  
Lu Chen ◽  
Shi Lun Xu ◽  
Pei Peng Xu ◽  
Ying De Cui ◽  
...  
Keyword(s):  
Soluble Sugars ◽  
Invertase Activity ◽  
Acid Invertase ◽  
Soluble Solids ◽  
Flavor Quality ◽  
Total Soluble Solids ◽  
Titratable Acid ◽  
Content Change ◽  
Variation Patterns

Gonggan（Citrus sinensis Osb. ‘Deqing Gonggan’）is a natural hybrid citrus from Guangdong province. To understand conflicting relationships between the change of flavor quality and total soluble solids and titratable acid contents of Gonggan fruits and study the method of flavor quality keeping at room temperature, we investigated that the flavor quality keeping role of aloin and its effects on soluble sugars contents, and acid invertase activity of Gonggan fruits. The results in this paper show that the change of flavor quality can be evaluated through soluble sugars（sucrose, glucose, fructose）contents, and also not through total soluble solids and titratable acid contents. Aloin reduced the changes of the inclusion contents of Gonggan fruits during storage, extended the flavor quality period from 7 to 15 days, changed the variation patterns of total soluble solids, soluble sugars（sucrose, glucose, fructose）contents and acid invertase activity from s-type of control into half-s-shaped. Its role in flavor quality keeping effect on fructose content change of Gonggan fruits is discussed.

scholarly journals Heat and cold stresses phenotypes of Arabidopsis thaliana calmodulin mutants: regulation of gamma-aminobutyric acid shunt pathway under temperature stress

2012 ◽  
Vol 3 (1) ◽  
pp. 2 ◽  
Author(s):  
Nisreen A. AL-Quraan ◽  
Robert D. Locy ◽  
Narendra K. Singh
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Stress ◽  
High Temperature ◽  
Seed Germination ◽  
Oxidative Damage ◽  
Temperature Stress ◽  
Wild Type ◽  
Gaba Shunt ◽  
Heat And Cold Stress

Plants have evolved mechanisms to cope with changes in surrounding temperatures. T-DNA insertions in seven calmodulin genes of <em>Arabidopsis thaliana</em> were used to investigate the role of specific calmodulin isoforms in tolerance of plants to low and high temperature for seed germination, susceptibility to low and high temperature induced oxidative damage, and changes in the levels of gammaaminobutyric acid (GABA) shunt metabolites in response to temperature stress. Exposure of wild type (WT) and <em>cam</em> mutant seeds at 4°C showed reduction in germination of <em>cam5-4</em> and <em>cam6-1</em> seeds. Exposure of cam seedlings to 42°C for 2 hr showed reduction in seed germination and survival of seedlings in <em>cam5-4</em> and <em>cam6-1</em> mutants compared to WT and other <em>cam</em> mutants. Oxidative damage by heat and cold stress measured as the level of malonaldehyde (MDA) was detected increased in root and shoot tissues of cam5- 4 and cam6-1. Oxidative damage by heat measured as the level of MDA was detected in root and shoot of most cam mutants with highest levels in <em>cam5-4</em> and <em>cam6-1</em>. Level of GABA shunt metabolites in seedlings were gradually increased after 1 hr and 3 hr with maximum level after 6 hr and 12 hr treatments at 4ºC. GABA shunt metabolites in both root and shoot were generally elevated after 30 min and 1 hr treatment at 42°C, and increased substantially after 2 hr at 42°C comparing to the control (no treatment). GABA and glutamate levels were increased significantly more than alanine in root and shoot tissues of all cam mutants and wild type compared to the control. Alanine levels showed significant decreases in all cam mutants and in WT for 30 and 60 min of heat stress. Sensitivity of <em>cam5-4 </em>and <em>cam6-1</em> to low temperatures suggests a role of the <em>CAM5</em> and <em>CAM6</em> genes in seed germination and protection against cold induced oxidative damage. Increases in the level of GABA shunt metabolites in response to cold treatment after initial reduction in some cam mutants suggests a role for calmodulin protein (<em>cam</em>) in the activation of glutamate decarboxylase (GAD) after exposure to cold, while increased metabolite levels may indicate involvement of other factors like reduction in cytoplasmic pH in cold regulation. Initial general elevation in GABA shunt metabolites after 30 min heat treatment in cam mutants suggests regulation of GABA level by <em>cam</em>. These data suggest that regulation by factors other than cam is likely, and that this factor may relate to the regulation of GAD by intracellular pH and/or metabolite partitioning under heat stress.

scholarly journals Alleviation of Heat Stress in Tomato by Exogenous Application of Sulfur

Horticulturae ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 21
Author(s):  
Muhammad Moaaz Ali ◽  
Muhammad Waleed Shafique ◽  
Shaista Gull ◽  
Waleed Afzal Naveed ◽  
Talha Javed ◽  
...  
Keyword(s):  
Heat Stress ◽  
Elementary Sulfur ◽  
Tomato Plants ◽  
Key Factor ◽  
Growth Chambers ◽  
Phosphorus And Potassium ◽  
Physiological And Biochemical ◽  
Nitrogen Phosphorus ◽  
Greenness Index

Temperature is a key factor influencing plant growth and productivity, however sudden increases in temperature can cause severe consequences in terms of crop performance. We evaluated the influence of elementary sulfur application on the physiology and growth of two tomato genotypes (“Ahmar” and “Roma”) grown in two growth chambers (at 25 and 45 °C). Plants were sprayed with 2, 4, 6, and 8 ppm sulfur 45 days after sowing (untreated plants were kept as control). Plants of the “Roma” cultivar receiving 6 ppm sulfur exhibited maximal shoot and root biomass values followed by those receiving 4 ppm under both temperature conditions. Maximal CO2 index, photosynthetic rate, transpiration rate, and greenness index values (188.1 µmol mol−1, 36.3 µmol CO2 m−2 s−1, 1.8 µmol H2O m−2 s−1, and 95 SPAD, respectively) were observed in plants of “Roma” cultivar grown at 25 °C, indicating positive influences of sulfur on tomato physiology. Similarly, sulfur maximized proline, nitrogen, phosphorus, and potassium contents in leaves of both genotypes at both temperatures. The differences between control and sulfur-treated plants grown under heat stress indicate a possible role of sulfur in mitigating heat stress. Overall, our results suggest that 6 ppm of sulfur is the best dose to alleviate tomato heat stress and enhance the morphological, physiological, and biochemical attributes of tomato plants.

scholarly journals 782 PB 424 INVERTASE ACTIVITY AND CARBOHYDRATE COMPOSITION IN DEVELOPING ANTIRRHINUM MAJUS L. FLOWERS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 545a-545
Author(s):  
Ricardo Campos ◽  
William B. Miller
Keyword(s):  
Flower Development ◽  
Developmental Stages ◽  
Specific Activity ◽  
Sucrose Concentration ◽  
Invertase Activity ◽  
Acid Invertase ◽  
Soluble Carbohydrates ◽  
Open Flower ◽  
Unknown Compound ◽  
Hexose Sugars

The relationship between the activity of soluble acid invertase and metabolism of soluble carbohydrates was investigated in snapdragon flowers. Flowers were harvested at three different developmental stages, and at four different dates. Soluble carbohydrates were extracted and analyzed by HPLC; invertase activity was determined in crude enzyme extracts. Sucrose concentration slowly increased throughout flower development from a closed bud to a fully open flower. Fructose and glucose concentration were relatively lower at the bud stage, increased during petal elongation, then slightly decreased at flower maturity. Mannitol concentration showed little change during flower development. An unknown compound increased in concentration during petal elongation and decreased at maturity. For all harvest dates, the specific activity of acid invertase increased with flower development. These results show a positive correlation of invertase activity and hexose sugars accumulation. It is possible that at maturity sugars are metabolized at a faster rate than produced, causing a slight decline in hexose sugars.

Ignition mechanism of mechanically activated Me–Si(Me = Ti, Nb, Mo) mixtures

2004 ◽  
Vol 19 (5) ◽  
pp. 1558-1566 ◽  
Author(s):  
U. Anselmi-Tamburini ◽  
F. Maglia ◽  
S. Doppiu ◽  
M. Monagheddu ◽  
G. Cocco ◽  
...  
Keyword(s):  
High Temperature ◽  
Reaction Mechanism ◽  
Mechanical Activation ◽  
Ignition Temperature ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Ignition Mechanism ◽  
Ignition Characteristics ◽  
Different Response

The influence of mechanical activation on the characteristics and mechanism of ignition of self-propagating high-temperature synthesis processes of different silicides in the systems Me–Si (Me =Ti, Nb, Mo) was investigated. The results show that mechanical activation does not alter the mechanism involved but influences significantly the ignition characteristics. The influence, however, strongly depends on the stoichiometry of the mixtures. The composition Ti:Si = 1:2 shows the largest influence, with the ignition temperatures decreasing from 1400 °C for unmilled powders to about 600 °C for powders milled for several hours. The compositionsTi:Si = 5:3, Nb:Si = 1:2 show less pronounced decreases, while the compositionMo:Si = 1:2 shows no decrease. These differences are discussed in terms of the role of microstructure in the reaction mechanism and the different response of the systems to contamination, particularly from oxygen. The results suggest that for these systems self-ignition processes during milling cannot be explained only on the basis of the decrease in the ignition temperature.

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