Effects of irrigation on seedling emergence and seedling survival of a desert shrub Haloxylon ammodendron (Chenopodiaceae)

2005 ◽  
Vol 53 (6) ◽  
pp. 529 ◽  
Author(s):  
Kazuo Tobe ◽  
Xiaoming Li ◽  
Kenji Omasa
Keyword(s):  
Seedling Establishment ◽  
Seedling Survival ◽  
Sand Dunes ◽  
Seedling Emergence ◽  
Coarse Sand ◽  
Early Spring ◽  
Burial Depth ◽  
Haloxylon Ammodendron ◽  
Seed Burial ◽  
Desert Sand

Haloxylon ammodendron (C.A. Mey) Bunge (Chenopodiaceae) is a shrub occurring on desert sand dunes in China. Seedling emergence and seedling survival were investigated by sowing seeds at different depths (0, 2.5, 5.0 or 10 mm) in fine or coarse sand in pots irrigated under different regimes. Seed burial in sand was required for seedling establishment of this species. Seedling emergence depended greatly on seed burial depth, sand type, and irrigation regime; this appeared to be due to (1) seeds or seedlings suffering from oxygen or moisture deficiency depending on the air : moisture ratio in sand, and/or (2) higher moisture content in sand resulting in hardening of the sand and obstruction of seedling growth. Increased irrigation resulted in longer survival of emerging seedlings because sand was moistened more deeply, and moisture in deeper sand persisted longer. The results suggest that the infrequent and light precipitation common in desert environments is likely to cause germination of many of the buried seeds, but is insufficient for emerging seedlings to survive. It is suggested that water from melting snow in early spring is crucial in enabling seedling establishment of this species in the deserts of China.

Seed germination and seedling emergence of three Artemisia species (Asteraceae) inhabiting desert sand dunes in China

2006 ◽  
Vol 16 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Kazuo Tobe ◽  
Liping Zhang ◽  
Kenji Omasa
Keyword(s):  
Seed Germination ◽  
Sand Dunes ◽  
Seedling Emergence ◽  
Light Sensitivity ◽  
Burial Depth ◽  
Secondary Effects ◽  
Seed Burial ◽  
Desert Sand ◽  
Light Fluence ◽  
Artemisia Species

Artemisia ordosica,A. arenariaandA. sphaerocephalaare semi-shrubs inhabiting desert sand dunes in China and often used to rehabilitate desertified areas. Improvement of dune rehabilitation success by sowing requires better understanding of the processes involved in the control of seed germination and seedling emergence in these species. Thus, (1) effects of temperature, light and osmotica (polyethylene glycol-6000) on seed germination, and (2) effects of seed burial depth in sand and irrigation regime on seedling emergence, were studied under controlled conditions. Seeds of the three species required light for germination, and the light fluence needed for germination was dependent on temperature. Seedling emergence of the three species was maximal (70–94%) for seeds sown at a depth of 2.5 mm, and decreased with increasing seed burial depth when the pots were initially and subsequently treated with 16 mm and 3 mm irrigation at 1-d intervals. However, when the pots were initially and subsequently treated with 8 mm and 3 mm irrigation at 2-d intervals, seedling emergence was almost completely suppressed due to water deficiency in sand. It is suggested that the probability of seed germination and seedling emergence of the three species in the field is very limited, because the light requirement restricts seed germination to shallow sand layers where water is lost rapidly due to evaporation. Temperature appeared to have secondary effects on seed germination, by modifying the light sensitivity of seeds.

scholarly journals The value of trophic interactions for ecosystem function: dung beetle communities influence seed burial and seedling recruitment in tropical forests

2016 ◽  
Vol 283 (1844) ◽  
pp. 20161634 ◽  
Author(s):  
Hannah M. Griffiths ◽  
Richard D. Bardgett ◽  
Julio Louzada ◽  
Jos Barlow
Keyword(s):  
Tropical Forests ◽  
Seedling Recruitment ◽  
Anthropogenic Impacts ◽  
Anthropogenic Activities ◽  
Seedling Emergence ◽  
Negative Relationship ◽  
Dung Beetle ◽  
Burial Depth ◽  
Seed Burial ◽  
Emergence Success

Anthropogenic activities are causing species extinctions, raising concerns about the consequences of changing biological communities for ecosystem functioning. To address this, we investigated how dung beetle communities influence seed burial and seedling recruitment in the Brazilian Amazon. First, we conducted a burial and retrieval experiment using seed mimics. We found that dung beetle biomass had a stronger positive effect on the burial of large than small beads, suggesting that anthropogenic reductions in large-bodied beetles will have the greatest effect on the secondary dispersal of large-seeded plant species. Second, we established mesocosm experiments in which dung beetle communities buried Myrciaria dubia seeds to examine plant emergence and survival. Contrary to expectations, we found that beetle diversity and biomass negatively influenced seedling emergence, but positively affected the survival of seedlings that emerged. Finally, we conducted germination trials to establish the optimum burial depth of experimental seeds, revealing a negative relationship between burial depth and seedling emergence success. Our results provide novel evidence that seed burial by dung beetles may be detrimental for the emergence of some seed species. However, we also detected positive impacts of beetle activity on seedling recruitment, which are probably because of their influence on soil properties. Overall, this study provides new evidence that anthropogenic impacts on dung beetle communities could influence the structure of tropical forests; in particular, their capacity to regenerate and continue to provide valuable functions and services.

scholarly journals Fatal germination in barnyardgrass (Echinochloa crus-galli)

2013 ◽  
Vol 49 (No. 4) ◽  
pp. 193-197 ◽  
Author(s):  
Z. Martinková ◽  
A. Honěk
Keyword(s):  
Seed Bank ◽  
Seedling Establishment ◽  
Burial Depth ◽  
Spring Season ◽  
Seed Burial ◽  
Pre Treatment ◽  
Germinated Seeds

Seeds of weeds buried by tillage may germinate at depths from which seedlings cannot establish. In barnyardgrass (Echinochloa crus-galli) we investigated how fatal germination was influenced by the depth and time of seed burial. The proportion of germinated seeds decreased with burial depth to 0–20% at ≥ 0.1 m depth which is fatal for seedling establishment. The percentage of fatal germination was greater for the seeds buried during the spring season than during autumn. Germination was influenced by seed pre-treatment, after ripening or stratification. Spring ploughing of non-dormant seeds below 0.1 m depth induces fatal germination, decreasing in this way seed bank of barnyardgrass.

Germination and seedling establishment in cashew (Anacardium occidentale L.): An interaction between seed size, relative growth rate and seedling biomass

2017 ◽  
Vol 45 (2) ◽  
pp. 110
Author(s):  
Babli Mog, J.D. Adiga M.G. Nayak and G.S. Mohana
Keyword(s):  
Leaf Area ◽  
Seed Size ◽  
Seedling Establishment ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Seed Mass ◽  
Germination Percentage ◽  
Mass Ratio ◽  
Unit Leaf ◽  
Seedling Biomass

<p>Seeds of cashew were used to determine the effect of seed mass (5.2 to 7.8 g) on germination, seedling emergence and growth<br />under nursery conditions. Germination percentage and germination time showed significant correlation with seed mass. Large<br />sized seeds had higher germination percentage (81.6%) and produced more vigorous seedlings. Per cent seedling emergence was<br />related to seed mass with large sized seeds exhibited faster emergence. Seed mass significantly affected seedling survival and<br />survival rate was high in seedlings arising from large sized seeds (62.9%). Seedling vigor expressed in terms of shoot and root<br />length, leaf number, leaf area and total dry matter was significantly affected by seed mass. Seedlings that emerged from large sized<br />seeds showed better growth and produced heavier seedlings as compared to medium sized seeds. RGR showed significant variation<br />(0.152 to 0.240 g g-1day-1) among two seed size classes positively correlated with seed mass, leaf area (LA), unit leaf rate per unit<br />leaf area (ULRM), root to shoot ratio (R/S) and root mass ratio (RMR) and negatively with stem mass ratio (SMR). The study<br />concluded that the seed mass and RGR have influence on seedling growth and success of seedling establishment in cashew.</p>

scholarly journals Germination ecology of Rhynchosia capitata: an emerging summer weed in Asia

2013 ◽  
Vol 31 (2) ◽  
pp. 249-257 ◽  
Author(s):  
H.H. Ali ◽  
A. Tanveer ◽  
M.A. Nadeem ◽  
H.N. Asghar ◽  
M.M. Javaid
Keyword(s):  
Seed Germination ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Ecological Factors ◽  
Moisture Stress ◽  
Burial Depth ◽  
Seed Burial ◽  
Germination Ability ◽  
Wide Range ◽  
The One

Rhynchosia capitata is becoming an increasing problem in summer crops, such as cotton, soybean, pearl millet and mungbean in many Asian countries. Laboratory and greenhouse studies have been conducted to determine the effects of several environmental factors on seed germination patterns and seedling emergence of R. capitata. We investigated whether the diverse ecological factors such as temperature, light, salinity, moisture stress, pH, and soil depth affected germination and seedling emergence of R. capitata. Germination increased as temperature increased from 25ºC and significantly reduced at 45ºC. Presence or absence of light did not influence germination. Germination of R. capitata was sensitive to increased salt and moisture stress, as well as to seed burial depth. Only 48% of seeds germinated at 150 mM salt concentration compared to 100% in control (distilled water). Similarly, 15% of seeds germinated at an osmotic potential of ‑0.8 MPa compared to 88% at ‑0.2 MPa. The optimum pH for seed germination of R. capitata was 7 (98% germination), but the seeds also germinated at lower level of pH 5 (85%) and at higher level of pH 10 (75%). In seed burial trial, maximum seedling emergence of 93% occurred at 2 cm depth, and seedling did not emerge from a depth of 12 cm. The high germination ability of R. capitata under a wide range of ecological factors suggests that this species is likely to be the one to cause more problems in a near future, if not managed appropriately.

Survival of seedling cohorts of a tropical legume on a sand dune system along the Gulf of Mexico: influence of germination date

1993 ◽  
Vol 71 (11) ◽  
pp. 1427-1433 ◽  
Author(s):  
M. Luisa Martinez ◽  
Patricia Moreno-Casasola
Keyword(s):  
Gulf Of Mexico ◽  
Seedling Survival ◽  
Sand Dunes ◽  
Seedling Emergence ◽  
Selective Advantage ◽  
Dune System ◽  
Winter Storms ◽  
Probability Of Survival ◽  
Different Seasons ◽  
Survival And Reproduction

Chamaecrista chamaecristoides is a legume endemic to the coastal sand dunes along the coasts of Mexico. Hard-coat dormancy of seeds is broken through naturally occurring temperature fluctuations, and seedlings can emerge and establish throughout the year. In the study site, winter storms (called Nortes) are responsible for moving large quantities of sand that bury young seedlings. The objectives of the study were (i) to elucidate the timing of seedling emergence, (ii) to investigate the effect of date of emergence on seedling survival, and (iii) to evaluate different factors of mortality. Seedling survival was monitored under natural conditions, from January 1988 to April 1991. Survivorship curves were compared using the log-rank Peto and Peto test. It was found that the probability of survival or reproduction was not strictly determined by chronological age but by size. Larger sized seedlings survived better during the Nortes. Timing of germination has a great impact on C. chamaecristoides populations, since it affects seedling growth possibilities and thus survival and reproduction. In a changing environment like the sand dunes, there seems to be a selective advantage for maintaining cohorts germinating during different seasons of the year. Key words: tropical sand dunes, seedling survival, Gulf of Mexico, cohorts, seedling size.

A Laboratory Exercise for Teaching Depth of Weed Emergence Concepts

2004 ◽  
Vol 18 (2) ◽  
pp. 473-479 ◽  
Author(s):  
Lance Gibson ◽  
Matt Liebman
Keyword(s):  
Student Perceptions ◽  
Seedling Emergence ◽  
Burial Depth ◽  
State University ◽  
Iowa State University ◽  
Seed Burial ◽  
Laboratory Exercise ◽  
Science Courses ◽  
Wild Mustard ◽  
Perceptions And Attitudes

The influence of weed seed burial depth on seedling emergence is a common and important topic in undergraduate weed science courses. A laboratory exercise was developed at Iowa State University to actively demonstrate changes in weed seedling emergence with increased seed-burial depth. Twenty-five ivyleaf morningglory and wild mustard seeds were sown in pots in monoculture, and the number of emerging seedlings was counted for 3 wk. The results from two semesters were analyzed to determine whether the experiment was successful in meeting its intended outcomes. Assessment of student perceptions and attitudes indicated that the activity increased students' understanding of weed biology; improved students' critical thinking, reading, and writing skills; and improved students' ability to make scientific observations, interpret graphical information, and analyze and summarize research data.

Effects of inoculum density, temperature, seeding depth, seeding date and fungicidal seed treatment on the impact of Rhizoctonia solani on lentil

2008 ◽  
Vol 88 (4) ◽  
pp. 799-809 ◽  
Author(s):  
K. F. Chang ◽  
S. F. Hwang ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
H. Wang ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Seedling Establishment ◽  
Root Rot ◽  
Seed Treatment ◽  
Field Experiments ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Inoculum Density ◽  
Seeding Date ◽  
The Impact

Rhizoctonia solani causes seedling blight and root rot in lentil, which reduces plant populations and the vigour and yield of surviving plants. Factors in the seedling environment, such as inoculum density, temperature, seeding depth, seeding date, and fungicidal seed treatment were studied to determine the degree to which they affect the impact of R. solani on lentil seedlings. Survival of lentil plants was evaluated after planting into soil artificially inoculated with various concentrations of a highly aggressive isolate of R. solani (AG-4). Emergence, seedling survival and shoot dry matter production decreased with increasing inoculum density, but these declines varied with temperature. Low soil temperatures delayed the emergence of lentil seedlings in non-inoculated soil, but in inoculated soils, emergence was inhibited with increasing temperatures. Depth of seeding did not affect seedling establishment, but root rot severity increased with depth of seeding in a growth cabinet trial. Root nodulation was reduced as root rot severity increased. In field experiments carried out over 3 station years, seeding date had a substantial effect on seedling emergence and yield of inoculated treatments, but the trends were not consistent between sites. In field assessments of fungicide efficacy, treatment of seed with thiabendazole plus carbathiin (Crown) and carbathiin plus thiram (Vitaflo 280) improved seedling establishment relative to the inoculated control. Key words: Lens culinaris, damping-off, root rot, seeding date, fungicide seed treatment depth of seeding, thiabendazole, carbathiin, thiram

Effect of Depth and Duration of Seed Burial on Kochia (Kochia scoparia)

Weed Science ◽  
1984 ◽  
Vol 32 (5) ◽  
pp. 602-607 ◽  
Author(s):  
Paul S. Zorner ◽  
Robert L. Zimdahl ◽  
Edward E. Schweizer
Keyword(s):  
Seedling Emergence ◽  
Burial Depth ◽  
Kochia Scoparia ◽  
Seed Burial ◽  
Deep Tillage ◽  
Seed Persistence ◽  
Tillage Practices ◽  
Viability Loss ◽  
Seed Loss

Dormant and nondormant kochia [Kochia scoparia(L.) Schrad. ♯3KCHSC] seed populations were buried at six soil depths in Colorado. Portions of both populations remained viable for 36 months. Persistence increased with burial depth in both populations. Seed loss from the initially dormant population was limited to germination in situ, but seed loss from the initially nondormant population included significant viability loss at burial depths of 10 cm or less. Persistence of both populations was regulated by dormancy retention. Shallow tillage practices are predicted to decrease seed persistence in soil and increase successful seedling emergence. Deep tillage practices are predicted to reduce seedling emergence but increase soil seed populations.

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