Effects of fire, post-fire defoliation, drought and season on regrowth and carbohydrate reserves of alpine snowgrass Poa fawcettiae (Poaceae)

2010 ◽  
Vol 58 (3) ◽  
pp. 157 ◽  
Author(s):  
A. D. Tolsma ◽  
K. G. Tolhurst ◽  
S. M. Read
Keyword(s):  
Cold Treatment ◽  
Soluble Carbohydrates ◽  
Warm Temperature ◽  
Drought Treatment ◽  
Carbohydrate Reserves ◽  
Vegetative Regeneration ◽  
Seasonal Factors ◽  
Growth Room ◽  
Tiller Mortality

Following defoliation, grasses regenerate foliage from basal buds. We used a combination of field, glasshouse and growth-room experiments to investigate the role of carbohydrate reserves in regrowth of Poa fawcettiae Vickery following fire or mock grazing, and the effect on reserve dynamics of post-fire defoliation, drought and seasonal factors. Fructan reserves of burnt plants were depleted during foliage regeneration, and remained below those of unburnt plants for up to 10 months in the field, and for up to 3 months in the glasshouse. Plants were resilient to occasional mechanical clipping of foliage, but experienced significant depletion in fructan reserves and high tiller mortality when clipped at frequent intervals. Cold treatment led to fructan concentrations almost double those in plants growing at a warm temperature, explaining peak autumn levels in field plants, whereas a short drought treatment doubled the concentration of ethanol-soluble carbohydrates. Taken together, these data show how the dynamics of carbohydrate reserves, and specifically tiller-base fructan reserves, explain the vegetative regeneration capacity of P. fawcettiae.

USE OF GIBBERELLIC ACID TO HASTEN FLOWERING IN RUTABAGA

1982 ◽  
Vol 62 (3) ◽  
pp. 823-826 ◽  
Author(s):  
A. ALI ◽  
V. SOUZA MACHADO
Keyword(s):  
Seed Production ◽  
Rapid Development ◽  
Cold Treatment ◽  
Flower Buds ◽  
Flower Bud ◽  
Breeding Programs ◽  
Bud Formation ◽  
Growth Room ◽  
Flower Bud Formation

In field conditions, rutabaga (Brassica napus ssp. Rapifera (Metzg.) Sinsk.) plants are biennials and require exposure to low temperature for completion of their life cycle to seed production state. When young rutabaga plants were thermoinduced (3–5 °C) for 8 wk and subsequently transferred to growth room conditions, formation of flower buds resulted in 6 wk. Flowering response was greatly enhanced if the plants were sprayed with GA3 (100 mg/L) prior to thermoinduction. Compared with untreated plants, the GA3-sprayed plants responded with flower bud formation after as little as 3 wk of cold treatment. A longer cold exposure (6–8 wk) of the GA3-sprayed plants resulted in rapid development and maturity of the inflorescence. This note emphasizes the pharmacological role of gibberellins as regulators of flowering and their usefulness to enhance seed production and plant breeding programs.

GRAS-domain transcription factor PAT1 regulates jasmonic acid biosynthesis in grape cold stress response

2021 ◽  
Author(s):  
Zemin Wang ◽  
Darren Chern Jan Wong ◽  
Yi Wang ◽  
Guangzhao Xu ◽  
Chong Ren ◽  
...  
Keyword(s):  
Stress Response ◽  
Cold Stress ◽  
Cold Tolerance ◽  
Cold Treatment ◽  
Ectopic Expression ◽  
Bimolecular Fluorescence Complementation ◽  
Luciferase Reporter ◽  
Vitis Amurensis ◽  
Mobility Shift

Abstract Cultivated grapevine (Vitis) is a highly valued horticultural crop, and cold stress affects its growth and productivity. Wild Amur grape (Vitis amurensis) PAT1 (Phytochrome A signal transduction 1, VaPAT1) is induced by low temperature, and ectopic expression of VaPAT1 enhances cold tolerance in Arabidopsis (Arabidopsis thaliana). However, little is known about the molecular mechanism of VaPAT1 during the cold stress response in grapevine. Here, we confirmed the overexpression of VaPAT1 in transformed grape calli enhanced cold tolerance. Yeast two-hybrid and bimolecular fluorescence complementation assays highlighted an interaction between VaPAT1 with INDETERMINATE-DOMAIN 3 (VaIDD3). A role of VaIDD3 in cold tolerance was also indicated. Transcriptome analysis revealed VaPAT1 and VaIDD3 overexpression and cold treatment coordinately modulate the expression of stress-related genes including lipoxygenase 3 (LOX3), a gene encoding a key jasmonate biosynthesis enzyme. Co-expression network analysis indicated LOX3 might be a downstream target of VaPAT1. Both electrophoretic mobility shift and dual luciferase reporter assays showed the VaPAT1-IDD3 complex binds to the IDD-box (AGACAAA) in the VaLOX3 promoter to activate its expression. Overexpression of both VaPAT1 and VaIDD3 increased the transcription of VaLOX3 and JA levels in transgenic grape calli. Conversely, VaPAT1-SRDX (dominant repression) and CRISPR/Cas9-mediated mutagenesis of PAT1-ED causing the loss of the C-terminus in grape calli dramatically prohibited the accumulation of VaLOX3 and JA levels during cold treatment. Together, these findings point to a pivotal role of VaPAT1 in the cold stress response in grape by regulating JA biosynthesis.

scholarly journals Sheep Digestive Physiology and Constituents of Feeds

2021 ◽  
Author(s):  
Samir Medjekal ◽  
Mouloud Ghadbane
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Early Stage ◽  
Growth Period ◽  
Cell Plate ◽  
Soluble Carbohydrates ◽  
Winter Period ◽  
The Common

Sheep have a gastrointestinal tract similar to that of other ruminants. Their stomach is made up of four digestive organs: the rumen, the reticulum, the omasum and the abomasum. The rumen plays a role in storing ingested foods, which are fermented by a complex anaerobic rumen microbiota population with different types of interactions, positive or negative, that can occur between their microbial populations. Sheep feeding is largely based on the use of natural or cultivated fodder, which is exploited in green by grazing during the growth period of the grass and in the form of fodder preserved during the winter period. Ruminant foods are essentially of plant origin, and their constituents belong to two types of structures: intracellular constituents and cell wall components. Cellular carbohydrates play a role of metabolites or energy reserves; soluble carbohydrates account for less than 10% dry matter (DM) of foods. The plant cell wall is multi-layered and consists of primary wall and secondary wall. Fundamentally, the walls are deposited at an early stage of growth. A central blade forms the common boundary layer between two adjacent cells and occupies the location of the cell plate. Most of the plant cell walls consist of polysaccharides (cellulose, hemicellulose and pectic substances) and lignin, these constituents being highly polymerized, as well as proteins and tannins.

scholarly journals Glutathione Protects Lactobacillus sanfranciscensis against Freeze-Thawing, Freeze-Drying, and Cold Treatment

2010 ◽  
Vol 76 (9) ◽  
pp. 2989-2996 ◽  
Author(s):  
Juan Zhang ◽  
Guo-Cheng Du ◽  
Yanping Zhang ◽  
Xian-Yan Liao ◽  
Miao Wang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Stress Responses ◽  
Freeze Drying ◽  
Unsaturated Fatty Acids ◽  
Cold Treatment ◽  
Protective Role ◽  
Intracellular Accumulation ◽  
Lactobacillus Sanfranciscensis

ABSTRACT Lactobacillus sanfranciscensis DSM20451 cells containing glutathione (GSH) displayed significantly higher resistance against cold stress induced by freeze-drying, freeze-thawing, and 4°C cold treatment than those without GSH. Cells containing GSH were capable of maintaining their membrane structure intact when exposed to freeze-thawing. In addition, cells containing GSH showed a higher proportion of unsaturated fatty acids in cell membranes upon long-term cold treatment. Subsequent studies revealed that the protective role of GSH against cryodamage of the cell membrane is partly due to preventing peroxidation of membrane fatty acids and protecting Na+,K+-ATPase. Intracellular accumulation of GSH enhanced the survival and the biotechnological performance of L. sanfranciscensis, suggesting that the robustness of starters for sourdough fermentation can be improved by selecting GSH-accumulating strains. Moreover, the results of this study may represent a further example of mechanisms for stress responses in lactic acid bacteria.

The Brain Damage Hypothesis of the Seasonality of Births in Schizophrenia and Major Affective Disorders: Evidence from Computerised Tomography

1992 ◽  
Vol 160 (3) ◽  
pp. 390-397 ◽  
Author(s):  
Emilio Sacchetti ◽  
Alessandro Calzeroni ◽  
Antonio Vita ◽  
Andrea Terzi ◽  
Franco Pollastro ◽  
...  
Keyword(s):  
Brain Damage ◽  
Affective Disorders ◽  
Early Spring ◽  
Early Summer ◽  
Cortical Atrophy ◽  
Primary Role ◽  
Seasonal Factors ◽  
History Of ◽  
The Brain

Although the excess of schizophrenic births in the winter and early spring has been replicated and some non-conclusive work supports the same seasonal birth trend in patients with major affective disorders, the aetiopathogenetic foundations of this phenomenon remain uncertain. The primary role of perinatal seasonal factors that predispose to the development of schizophrenia via induction of brain damage has been invoked, as has a tendency for patients to conceive during the spring and early summer. In order to test these two hypotheses, cerebral ventricular size and cortical atrophy in 206 schizophrenics and 107 patients with major affective disorders were assessed by CT and analysed in relation to month of birth. Compared with schizophrenics born during the remainder of the year, those born between December and April, particularly in cases lacking a family history of schizophrenia, showed increased chances for ventricular enlargement, but not for cortical atrophy. No association between season of birth and central or cortical atrophy was found for patients with major affective disorders. This suggests that the brain-damaging effect played by perinatal seasonal factors has both a disease and an anatomical specificity.

scholarly journals Role of Polyhydroxybutyrate and Glycogen as Carbon Storage Compounds in Pea and Bean Bacteroids

2005 ◽  
Vol 18 (1) ◽  
pp. 67-74 ◽  
Author(s):  
E. M. Lodwig ◽  
M. Leonard ◽  
S. Marroqui ◽  
T. R. Wheeler ◽  
K. Findlay ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Rhizobium Leguminosarum ◽  
Glycogen Synthase ◽  
Wild Type ◽  
Symbiotic Efficiency ◽  
Storage Compounds ◽  
Bean Plants ◽  
Growth Room ◽  
Main Carbon

Rhizobium leguminosarum synthesizes polyhydroxybutyrate and glycogen as its main carbon storage compounds. To examine the role of these compounds in bacteroid development and in symbiotic efficiency, single and double mutants of R. leguminosarum bv. viciae were made which lack poly-hydroxybutyrate synthase (phaC), glycogen synthase (glgA), or both. For comparison, a single phaC mutant also was isolated in a bean-nodulating strain of R. leguminosarum bv. phaseoli. In one large glasshouse trial, the growth of pea plants inoculated with the R. leguminosarum bv. viciae phaC mutant were significantly reduced compared with wild-type-inoculated plants. However, in subsequent glasshouse and growth-room studies, the growth of pea plants inoculated with the mutant were similar to wild-type-inoculated plants. Bean plants were unaffected by the loss of polyhydroxybutyrate biosynthesis in bacteroids. Pea plants nodulated by a glycogen synthase mutant, or the glgA/phaC double mutant, grew as well as the wild type in growth-room experiments. Light and electron micrographs revealed that pea nodules infected with the glgA mutant accumulated large amounts of starch in the II/III interzone. This suggests that glycogen may be the dominant carbon storage compound in pea bacteroids. Polyhydroxybutyrate was present in bacteria in the infection thread of pea plants but was broken down during bacteroid formation. In nodules infected with a phaC mutant of R. leguminosarum bv. viciae, there was a drop in the amount of starch in the II/III interzone, where bacteroids form. Therefore, we propose a carbon burst hypothesis for bacteroid formation, where polyhydroxybutyrate accumulated by bacteria is degraded to fuel bacteroid differentiation.

SOME EFFECTS OF NITRATE ON SOYBEAN ROOT DEVELOPMENT

1986 ◽  
Vol 66 (3) ◽  
pp. 505-510 ◽  
Author(s):  
J. A. STONE ◽  
B. R. BUTTERY
Keyword(s):  
Glycine Max ◽  
Field Test ◽  
Dry Weight ◽  
Nodule Development ◽  
Root Extension ◽  
Morphological Aspects ◽  
Growth Room ◽  
Glycine Max L ◽  
Top Dry Weight

The objective of this study was to determine the effect of nitrate on some morphological aspects of soybean (Glycine max (L.) Merr.) root growth and to determine the role of drainage in the response. Two indeterminate soybean cultivars were grown on 0, 10 and 40% mixtures of perlite and Brookston clay loam, supplied with Bradyrhizobium japonicum strain USDA 110, and watered with nutrient solutions containing 0 or 6 mM nitrate. Plants were grown in acrylic tubes until 21 and 53 d after emergence in corresponding field and growth room experiments, respectively. Response variables measured were the rate of taproot extension, root counts at the acrylic-soil interface, and top, root, and nodule dry weight. Nitrate suppressed nodule development and increased top dry weight but had no effect on the rate of taproot extension. Nitrate increased root counts and root dry weights in the field test, but decreased root counts in the growth room test. Top:root ratio was increased in the growth room but not in the field test. Increasing the proportion of perlite generally increased rates of root extension, root counts, and top dry weights in the field and growth room experiments. However, the soil mixture had no effect on nodule dry weight at either location, or on root dry weight in the growth room.Key words: Root extension, Glycine max, indeterminate, drainage

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