Effects of seed age and seeding depth on growth of Stipa lagascae R. & Sch. seedlings

2006 ◽  
Vol 65 (4) ◽  
pp. 682-687 ◽  
Author(s):  
A. Ouled Belgacem ◽  
M. Neffati ◽  
V.P. Papanastasis ◽  
M. Chaieb
Keyword(s):  
Seed Age ◽  
Stipa Lagascae

scholarly journals Potential Propagation by Seed and Cuttings of the Azorean NativeCalluna vulgaris(L.) Hull

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Maria João Pereira ◽  
Helena Fagundo ◽  
Tiago Menezes ◽  
João Couto
Keyword(s):  
Room Temperature ◽  
Seed Storage ◽  
Calluna Vulgaris ◽  
Landscape Conservation ◽  
Wild Populations ◽  
Surface Sterilization ◽  
Cultural Conditions ◽  
Germination Characteristics ◽  
Seed Age ◽  
Natural Stands

This work investigates the potential propagation by seed and cuttings of the Azorean nativeCalluna vulgaris(L.) Hull. for landscape conservation. With that purpose we have performed several germination and cuttings trials, using plant material from wild populations of this species. In the germination trials, we tested the effects of photoperiod length (8 and 16 h), temperature (10, 15, 20, and 20–10°C), seed age (6, 108, and 270 days), temperature of seed storage (4°C and room temperature), and seed surface sterilization on the germination characteristics. In the cuttings trials, we tested the effects of stem cutting type, cultural conditions, cuttings’ harvest month, and rooting substrates on the rooting percentages. The best percentages of germination, 93 and 90%, were obtained with fresh seeds and surface sterilized and sown under an 8 h photoperiod and with temperatures of 10°C or 15°C, respectively; germination after seed storage during 270 days is significantly superior (71%) when seeds are stored at 4°C. The best percentages of rooting were achieved for straight (96%) or heel cuttings (90%) harvested in March, planted on soil from natural stands ofC. vulgarisandErica azoricaHochst., outdoors in half shade, and partially covered with transparent polyethylene film.

Soybean seed vigour and field emergence under influence of cultivar, seed age and planting date

2007 ◽  
Vol 35 (2) ◽  
pp. 177-180 ◽  
Author(s):  
Luka Andric ◽  
Tihana Teklic ◽  
Marija Vrataric ◽  
Aleksandra Sudaric ◽  
Vinko Duvnjak
Keyword(s):  
Soybean Seed ◽  
Planting Date ◽  
Seed Vigour ◽  
Seed Age ◽  
Field Emergence

scholarly journals Predicting Leaf Trait Variability as a Functional Descriptor of the Effect of Climate Change in Three Perennial Grasses

Diversity ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 233
Author(s):  
Marwa Hamdani ◽  
Khouloud Krichen ◽  
Mohamed Chaieb
Keyword(s):  
Functional Traits ◽  
Leaf Traits ◽  
Perennial Grasses ◽  
Arid Ecosystems ◽  
Leaf Trait ◽  
Grassland Species ◽  
Dimensional Shrinkage ◽  
Potential Link ◽  
Dehydration Avoidance ◽  
Stipa Lagascae

Aims of the study: The most important trends of the current climate variability is the scarcity of rains that affects arid ecosystems. The aim of this study was to explore the variability of leaf functional traits by which grassland species survive and resist drought and to investigate the potential link between resource use efficiency and water scarcity resistance strategies of species. Methods: Three grasses (Cenchrus ciliaris (C4), Stipa parviflora and Stipa lagascae (C3)) were established in a randomized block consisting of eleven replications. The seedlings were kept under increasing levels of water stress. In addition to their functional leaf traits, the rate of water loss and dimensional shrinkage were also measured. Key Results: Thicker and denser leaves, with higher dry matter contents, low specific leaf area and great capacity of water retention are considered among the grasses’ strategies of dehydration avoidance. Significant differences between the means of the functional traits were obtained. Furthermore, strong correlations among leaf traits were also detected (Spearman’s r exceeding 0.8). Conclusions: The results provide evidence that the studied grasses respond differently to drought by exhibiting a range of interspecific functional strategies that may ameliorate the resilience of grassland species communities under extreme drought events.

Dormancy Variations in Common Purslane Seeds

Weed Science ◽  
1974 ◽  
Vol 22 (6) ◽  
pp. 535-540 ◽  
Author(s):  
G. H. Egley
Keyword(s):  
Water Content ◽  
Seed Viability ◽  
High Water ◽  
High Water Content ◽  
Water Imbibition ◽  
Immature Seeds ◽  
Seed Age ◽  
Common Purslane ◽  
Black Seeds ◽  
Mature Seeds

Common purslane (Portulaca oleraceaL.) seeds, produced by the same plants, had different degrees of dormancy. The dormancy variations were caused neither by low seed viability nor by location on the plant where seeds were produced. Seed water content and seed age at time of collection contributed to, but were not solely responsible for, the dormancy variations. Immature, brown seeds of high water content were less dormant than the more mature, black seeds of low water content. The immature seeds germinated better in the dark than did the more mature seeds. A puncture in the seed, over the radicle, broke purslane dormancy. Dormancy was not caused by blockage of water imbibition by seeds. Purslane dormancy developed during later stages of seed maturation on the mother plant.

Physiological, anatomical and antioxidant responses to salinity in the Mediterranean pastoral grass plant Stipa lagascae

2017 ◽  
Vol 68 (9) ◽  
pp. 872 ◽  
Author(s):  
Raoudha Abdellaoui ◽  
Fayçal Boughalleb ◽  
Zohra Chebil ◽  
Maher Mahmoudi ◽  
Azaiez Ouled Belgacem
Keyword(s):  
Glutathione Reductase ◽  
Ascorbate Peroxidase ◽  
Osmotic Adjustment ◽  
Perennial Grass ◽  
Soluble Sugars ◽  
Ros Scavenging ◽  
Total Soluble Sugars ◽  
Chlorophyll Pigments ◽  
Moderate Salinity ◽  
Stipa Lagascae

Soil and water salinity is a major environmental problem in the dry Mediterranean regions, affecting rangeland production. This study investigated the effects of salinity on the wild perennial grass (Poaceae) species Stipa lagascae R. & Sch., a potential forage plant that could be used to rehabilitate degraded rangelands in dry areas. In a laboratory, 3-month-old S. lagascae seedlings were subjected to increasing salt treatments (0–400 mm NaCl) for 45 days. Physiological and biochemical parameters such as leaf water potential (Ψw), leaf relative water content (RWC), proline, total soluble sugars, Na+, K+ and Ca2+ contents, and catalase, ascorbate peroxidase and glutathione reductase activities were measured. Total soluble sugars and proline concentrations increased and Ψw and RWC decreased with increasing salt concentrations. Lower salt concentrations induced a non-significant degradation of chlorophyll pigments. Shoot Na+ content increased with a salinity level, whereas shoot K+ and Ca2+ concentrations decreased and the K+ : Na+ ratio was lower. The salinity threshold, above which S. lagascae showed signs of damage, occurred at 300 mm. Plants have evolved reactive oxygen species (ROS) scavenging enzymes including catalase, ascorbate peroxidase and glutathione reductase, which provide cells with an efficient mechanism to neutralise ROS. The tolerance strategies of S. lagascae to moderate salinity seem to include osmotic adjustment through total soluble sugars and proline accumulation, and highly inducible antioxidative defence. Further investigations are necessary to study the effect of salt stress on distribution of ions (Na+, K+, Ca2+, Mg2+, Cl–, NO3–, SO42–) and osmotic adjustment. Photosynthesis and water-use efficiency parameters could be also useful tools.

Anatomical adaptations of the desert species Stipa lagascae against drought stress

Biologia ◽  
2015 ◽  
Vol 70 (8) ◽  
Author(s):  
Façal Boughalleb ◽  
Raoudha Abdellaoui ◽  
Zied Hadded ◽  
Mohammed Neffati
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Deficit ◽  
Cortical Cell ◽  
Severe Drought ◽  
Leaf Rolling ◽  
Drought Period ◽  
Severe Water Deficit ◽  
Anatomical Adaptations ◽  
Stipa Lagascae

AbstractStipa lagascae R. & Sch. (perennial bunchgrass) is one of the most promising steppic species for arid and desert lands of Tunisia. The present study was designed to study the effect of drought on root and leaf anatomy, water relationship, and the growth of three- month-old S. lagascae plants, submitted to water deficit (5, 10, 15, 20, 30 days of withheld irrigation) and grown in pots in greenhouse conditions. The results show that water deficit treatments reduced the biomass accumulation (MS) and leaf water potential (Ψw) of plants. However, leaf relative water content (RWC) decreased significantly only at severe drought. The root’s anatomical features showed reduced root cross-sectional diameter under water deficit. Conversely, epidermis was unaffected by water stress. Moderate and/or severe water deficit (20-30 days) reduced significantly the cortex thickness, cortical cell size, stele diameter, xylem vessel diameter and the stele/root crosssectional ratio, while the number of cortical cells increased for severe water deficit. The cuticles and mesophyll of S. lagascae was thickened by moderate to severe drought and the entire lamina thickness was increased significantly by 5.8% only after 30 days of water deficit while epidermis was unaffected by water deficit. However, severe water deficit (30 days) decreased the width and the length of the bundle sheath. At the same time, the mesophyll cells size and both the xylem and phloem vessels diameter diminished by 12, 16.8 and 17.5%, respectively. Leaf rolling occurs as a response to water deficit and its level increases as the drought period is progressing in plants while reduced bulliform cells size occurred only at severe water deficit. Our findings suggest a complex network of root and leaf anatomical adaptations such as a reduced vessel size with lesser cortical and mesophyll parenchyma formation and increased leaf rolling. These proprieties are required for the maintenance of water potential and energy storage under water stress which can improve the resistance of S. lagascae to survive in extremely arid areas

Role of mucilage in seed dispersal and germination of the annual ephemeral Alyssum minus (Brassicaceae)

2012 ◽  
Vol 60 (5) ◽  
pp. 439 ◽  
Author(s):  
Ying Sun ◽  
Dun Y. Tan ◽  
Carol C. Baskin ◽  
Jerry M. Baskin
Keyword(s):  
Water Stress ◽  
Seed Dispersal ◽  
Incubation Temperature ◽  
Water Reservoir ◽  
Soil Surface ◽  
Moisture Stress ◽  
West China ◽  
North West ◽  
Seed Age

Seeds of Alyssum minus, an annual ephemeral in shrublands of north-west China, can produce a large amount of mucilage. The primary aim of this study was to explore the role of mucilage in seed dispersal, settlement onto the soil surface and germination of this species. Width of imbibed seeds with mucilage was three times greater than that of seeds without mucilage, and mass of mucilage increased 167 times after imbibition. Expanded dry mucilage significantly increased wind dispersal of seeds. Floating time on water was greatest for seeds without mucilage, and adherence of soil particles to seeds was greater for seeds with mucilage than for those without mucilage. Mucilage increased rate of water uptake and decreased rate of water loss, and it significantly decreased germination of 0- and 4-week-old seeds. Gibberellic acid promoted germination of 0- and 4-week-old seeds with and without mucilage, but its effect depended on seed age and incubation temperature. Seeds with mucilage subjected to water stress during imbibition and/or incubation germinated faster than those without mucilage. Presence of mucilage on seeds during imbibition significantly increased germination percentages under increased water stress, a first report of this phenomenon. The study has shown that the mucilage of A. minus plays an important role in seed dispersal, seed adhesion to soil (thereby minimising removal by water and predators), seed hydration via increasing surface contact with the substrate, and can serve as a water reservoir for germination, especially under moisture stress.

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