Drought survival and dehydration tolerance in Dactylis glomerata and Poa bulbosa

2001 ◽  
Vol 28 (8) ◽  
pp. 743 ◽  
Author(s):  
Florence Volaire ◽  
Geneviève Conéjero ◽  
François Lelièvre
Keyword(s):  
Water Content ◽  
Water Status ◽  
Water Soluble ◽  
Perennial Grasses ◽  
Soluble Carbohydrate ◽  
Plant Responses ◽  
Dehydration Tolerance ◽  
Carbohydrate Concentration ◽  
Drought Survival ◽  
Final Water Content

To analyse the contribution of dormancy and dehydration tolerance to drought survival of perennial grasses, we compared Poa bulbosa L., which is classified as a resurrection plant, with one of the most drought resistant cultivars of MediterraneanDactylis glomerata L. Comparing periods when dormancy was induced in Poa (summer) and not induced (winter), we aimed to ascertain the presence of differential plant responses between dormancy and dehydration tolerance and to characterise water status, sugar and dehydrin accumulation in surviving organs of Poa and Dactylis, in relation to their ability to survive intense drought. Irrespective of the dormancy status of Poa, the bulbs of this species had a final water content lower than 10% and survived an extreme drought. This could be associated with the accumulation of sucrose and the expression of a high number (>10) of dehydrins that peaked when the water content of the bulbs fell below 50%, whether this dehydration was due to dormancy induction or increasing soil water deficit. The independence of dormancy to dehydration tolerance was reinforced by the expression of a specific dehydrin (approx. 28 kDa) found only in irrigated, but dormant, tissues of Poa. The Dactylis exhibited contrasting survival between experiments (46 and 0% after a summer and winter drought, respectively). The mortality was associated with a significantly higher rate of decrease of the membrane stability of leaf bases of Dactylis in winter and with barely detectable amounts of sucrose contents in droughted roots. However, neither the water-soluble carbohydrate concentration in leaf bases nor the overall accumulation of dehydrins could be related to the contrasting survival of this Dactylis between the two seasons. Since in seeds of Poa and Dactylis, the accumulation of dehydrins was comparable with that found in droughted aerial tissues of the same species, the expression of these proteins must interact with other mechanisms to confer dehydration tolerance.

Canopy morphology and nutritional quality traits as potential grazing value indicators for Lolium perenne varieties

2002 ◽  
Vol 139 (3) ◽  
pp. 257-273 ◽  
Author(s):  
T. J. GILLILAND ◽  
P. D. BARRETT ◽  
R. L. MANN ◽  
R. E. AGNEW ◽  
A. M. FEARON
Keyword(s):  
Lolium Perenne ◽  
Nutritive Value ◽  
Canopy Structure ◽  
Total Lipid Content ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Carbohydrate Concentration ◽  
Harvest Year ◽  
Water Soluble Carbohydrate ◽  
Testing Protocols

Twelve perennial ryegrass (Lolium perenne L.) varieties of different ploidy and maturity classifications were compared under a frequent cutting management in their second harvest year, equivalent to the simulated rotational grazing system employed in UK testing protocols. Varietal differences in canopy structure (proportion of lamina, green leaf mass, sward surface height, extended tiller height, bulk density) and in herbage nutritive value factors (water-soluble carbohydrate content and proportion of linoleic and α-linolenic fatty acids) were assessed and their importance evaluated with reference to total herbage production. Significant variety variation (P<0·001) was recorded in the annual means of all the canopy structure characteristics. Significant differences associated with ploidy were also recorded, with tetraploid varieties having significantly higher values than diploids in most plant characters, indicating better intake characteristics for these grasses. Temporal patterns of variation associated with maturity were also observed in several characters, thus making it impossible to designate a single assessment that would be representative of the annual ranking of varieties. Water-soluble carbohydrate concentration differed significantly (P<0·001) between varieties and although the tetraploids tended to have high contents, the highest value of all was recorded in a diploid variety, which had been selectively bred for this trait. The varieties did not differ in total lipid content but there were significant differences in the proportion of linoleic acid between varieties (P<0·001) while the proportion of α-linolenic acid differed between varieties (P<0·001), ploidy (P<0·001) and maturity (P<0·05) classes.Overall evaluation of the extensive variety variation highlighted the need for better quantification of animal responses to differences of these magnitudes, before the high workload of including them in routine variety testing protocols could be justified. Potential for breeding improvement in these factors was also indicated and the future prospects for their use in farmer decision support systems was considered.

scholarly journals Additive Type Affects Fermentation, Aerobic Stability and Mycotoxin Formation during Air Exposure of Early-Cut Rye (Secale cereale L.) Silage

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1432
Author(s):  
Horst Auerbach ◽  
Peter Theobald
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Water Soluble ◽  
Potassium Sorbate ◽  
Soluble Carbohydrate ◽  
Chemical Additives ◽  
Air Exposure ◽  
Carbohydrate Concentration ◽  
Aerobic Stability ◽  
Silage Production

Whole-crop rye harvested before maturity represents a valuable forage for silage production. Due to the scarcity of data on fermentation characteristics and aerobic stability (ASTA) and the lack of information on mycotoxin formation during aeration of early-cut rye (ECR) silage after silo opening, we evaluated the effects of different additive types and compositions. Wilted forage was treated with various biological and chemical additives, ensiled in 1.5-L glass jars and stored for 64 days. Fermentation pattern, yeast and mould counts and ASTA were determined at silo opening. In total 34 mycotoxins were analysed in wilted forage and in silage before and after 240 h of air exposure. Chemical additives caused the lowest dry matter (DM) losses during fermentation accompanied with the lowest ethanol production and the highest water-soluble carbohydrate concentration. Aerobic deterioration, which started within two days after silo opening in silage left untreated and inoculated with homofermentative lactic acid bacteria, was prevented by the combined use of hetero- and homofermentative lactic acid bacteria and the chemical additive containing sodium nitrite, hexamethylene tetramine and potassium sorbate. Moreover, these two additives largely restricted the formation of the mycotoxin roquefortine C to < 0.05 mg kg−1 DM after aeration, whereas untreated silage contained 85.2 mg kg−1 DM.

INFLUENCE OF A NANOSEILE ON THE CONTENTS OF K+, Nа+ AND Cl— IONS IN WHEAT SEEDS IN THE CONDITIONS OF THE COMBINED ACTION OF SALTING AND DRAIN

2020 ◽  
Vol 6(72) (1) ◽  
pp. 220-230
Author(s):  
I. N. Yurkova ◽  
A. V. Omelchenko ◽  
A. A. Zubochenko ◽  
D. A. Panov ◽  
I. L. Danilova
Keyword(s):  
Protective Effect ◽  
Water Content ◽  
Water Status ◽  
Soil Salinization ◽  
Water Soluble ◽  
Biologically Active ◽  
River Sand ◽  
Wheat Seedlings ◽  
Leaves And Roots ◽  
Wheat Seeds

Soil salinization is one of the most important problems for agriculture. In most cases, the effect of salinization is manifested in conjunction with water deficiency, reinforcing each other. One of the most dangerous types of salinization is sodium chloride, in which both sodium and chlorine ions have a damaging effect on plants. The physiological processes taking place under stressful conditions with the participation of enzymes and antioxidants are closely related to each other. The content of some enzymes is significantly affected by selenium. The least toxic and bioavailable is selenium in the form of nanoparticles stabilized by natural biologically active substances. The aim of the work was to study the effect of the tread action of the original water-soluble composition of nanosalen stabilized with sodium alginate on the content of K+, Na+ and Cl— ions in wheat seedlings under the combined effects of salinization and drought. The objects of study were winter wheat seeds (Triticum aestivum L.) and a water-soluble composition of selenium nanoparticles. Wheat seeds were soaked for 4 hours in a solution of selenium nanocomposition at a concentration of 10.0; 20.0 and 30.0 mg/l. The control was seeds soaked in distilled water. Plants were grown for 10 days under controlled conditions in a climatic chamber in vessels with a capacity of 1.0 L., a 16-hour photoperiod, a temperature of 25/20 °C (day / night) and a relative humidity of 60±5 %. Well washed river sand was used as a substrate. On day 10, the mass of raw and dry matter and the content of K+, Na+ and Cl— ions in the leaves and roots, as well as on the water content of the leaf tissues and the relative water content (RWC) were determined. For the first time, a study was made of the protective effect of selenium nanocomposite on the content of K+, Na+ and Cl— in leaves and roots, as well as their relationship with the water status of leaves in wheat seedlings under the combined effect of chloride salinity and drought. The action of nanoselen increases the absorption of K+ ions by both roots and leaves. In this case, the absorption of Na+ ions are significantly reduced. The protective effect of nanoselen is also manifested in maintaining a high-water status.

Sign in / Sign up

Export Citation Format

Share Document