scholarly journals GROWTH RESPONSES OF PALM SEEDLINGS TO DIFFERENT LIGHT INTENSITIES STIMULATING CANOPY GAPS WITH AN ECOPHYSIOLOGICAL APPROACH

REINWARDTIA ◽  
2016 ◽  
Vol 15 (2) ◽  
pp. 81
Author(s):  
DIAN LATIFAH ◽  
ROBERT A. CONGDON ◽  
JOSEPH A. HOLTUM
Keyword(s):  
Seedling Growth ◽  
Canopy Gaps ◽  
Growth Responses ◽  
Marginal Lands ◽  
Light Intensities ◽  
Disturbed Areas ◽  
Shade Cloth ◽  
Leaf Turnover ◽  
Pot Trials ◽  
Below Ground

LATIFAH, D., CONGDON, R. A. & HOLTUM, J. A. 2016. Growth responses of palm seedlings to different light intensities stimulating canopy gaps with an ecophysiological approach. Reinwardtia 15(2): 81 – 98. — Palms (Arecaceae) mainly grow in rainforests and many occur in disturbed areas like canopy gaps created by natural disturbances such as cyclones in Australia. Knowledge of seedling growth in different light intensities is essential to assist rainforest restoration in disturbed or marginal lands. The aim of this research was to investigate the effects of different light intensities on the seedling growth of Arenga australasica (H. Wendl. & Drude) S. T. Blake ex H. E. Moore, Calamus australis Mart., C. moti F. M. Bailey, Hydriastele wendlandiana (F. Muell.) H. Wendl. & Drude and Licuala ramsayi (F. Muell.) H. Wendl. & Drude. Seedling growth experiments (pot trials) were conducted in a glass house using shade cloth providing four different levels of shading: 59, 29, 17 and 6% sunlight. The growth rate, leaf turnover, leaf area, total chlorophyll, chlorophyll a:b ratio, vigor, above-ground and below-ground biomass and growth indices (LAR, SLA and LWR) of palm seedlings were measured. As a result of these measurements the relative shade tolerance of the five species was determined. The seedlings of Arenga australasica were classified as intermediate-shade intolerant species. Hydriastele wendlandiana seedlings were shade-intolerant. Calamus australis and C. moti seedlings are intermediate-shade intolerant. Licuala ramsayi seedlings were found to be a shade-tolerant.

Seedling Growth Responses of Buffelgrass (Pennisetum ciliare) to Tebuthiuron and Honey Mesquite (Prosopis glandulosa)

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 88-93 ◽  
Author(s):  
G. Allen Rasmussen ◽  
Roger P. Smith ◽  
Charles J. Scifres
Keyword(s):  
Seedling Growth ◽  
Woody Plants ◽  
Prosopis Glandulosa ◽  
Average Height ◽  
Growth Responses ◽  
Soil Columns ◽  
Pennisetum Ciliare ◽  
Shoot Weight ◽  
Soil Changes ◽  
Honey Mesquite

Tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} at 2 or 4 ppmw placed 0 to 3, 8 to 11, or 15 to 18 cm deep in soil columns reduced root and shoot weights of buffelgrass [Pennisetum ciliare(L.) Link # PESCI] 30 days after emergence. Plains bristlegrass (Setaria macrostachyaH.B.K.) seedling shoot weights were not reduced when 2 ppmw tebuthiuron was placed 8 to 11 cm deep or deeper. Effects of tebuthiuron at 0.13 to 0.50 ppmw on buffelgrass shoot and net tiller production were not moderated by the presence of honey mesquite (Prosopis glandulosa# PRCJG) in the pots. However, regardless of tebuthiuron dosage, average height and shoot weight of buffelgrass seedlings were greater when seedlings were grown in soil collected from beneath honey mesquite canopies compared to growth in soil from interspaces. Therefore, spatial variations in buffelgrass response to applications of tebuthiuron for control of invading shrubs may largely be attributed to soil changes induced by woody plants rather than to presence of shrubs.

scholarly journals Responses of Foreign GA3 Application on Seedling Growth of Castor Bean (Ricinus communis L.) under Salinity Stress Conditions

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 274
Author(s):  
Xiurong Jiao ◽  
Wenfang Zhi ◽  
Guijuan Liu ◽  
Guanglong Zhu ◽  
Gongneng Feng ◽  
...  
Keyword(s):  
Plant Height ◽  
Seedling Growth ◽  
Castor Bean ◽  
Ricinus Communis ◽  
Proline Content ◽  
Stem Diameter ◽  
Saline Soils ◽  
Salt Tolerant ◽  
Marginal Lands ◽  
Ricinus Communis L

Castor bean (Ricinus communis L.), a promising bioenergy crop, is readily planted in marginal lands like saline soils. A controlled experiment was conducted to explore the possibility of using gibberellic acid (GA3) as a promoter for caster bean grown under NaCl conditions and to try to determine the most appropriate concentration of GA3 for seedling growth. The seeds of salt-tolerant cultivar Zibi 5 were firstly soaked with 0, 200, 250, and 300 µM GA3 for 12 h and then cultured with 1/2 Hoagland solution containing 0, 50, and 100 mM NaCl in pots filled with sand. Plant height, stem diameter, leaf area, dry mater of each organ, activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), soluble protein, and proline content in the leaves were examined. Plant height and stem diameter, SOD, and POD activity was significantly highest in the treatment of 250 µM GA3 under salt concentration of 50 mM NaCl among all the testing days; protein content was highest when GA3 concentration was 250 µM under 100 mM NaCl treatment. This indicated that caster bean seed soaking with 250 µM GA3 could be the most suitable concentration for promoting seedling growth of caster bean, improving their stress resistance.

scholarly journals Soil Changes and Tree Seedling Response Associated with Site Preparation in Northern Idaho

1997 ◽  
Vol 12 (3) ◽  
pp. 81-88 ◽  
Author(s):  
Deborah S. Page-Dumroese ◽  
Martin F. Jurgensen ◽  
Alan E. Harvey ◽  
Russell T. Graham ◽  
Jonalea R. Tonn
Keyword(s):  
Seedling Growth ◽  
Soil Nutrient ◽  
Soil Surface ◽  
Nutrient Status ◽  
Site Preparation ◽  
Pinus Monticola ◽  
Growth Responses ◽  
Tree Seedling ◽  
Competing Vegetation ◽  
Northern Idaho

Abstract Conifer regeneration in western North America is often hampered by low soil moisture, poor soil nutrient status, and competing vegetation. Three site preparation techniques were evaluated at two different elevations in northern Idaho as potential remedies for these problems: (1) soil mounds without control of competing vegetation, (2) soil mounds with herbicidal control of competing vegetation, and (3) scalping (removal of soil surface organic horizons and mineral topsoil). Treatments were evaluated for effects on soil nutrient levels, soil physical properties, and the growth of Douglas-fir (Pseudotsuga menziesii var. glauca) and western white pine (Pinus monticola) seedlings. Both species generally grew best when planted in the mounded treatment with competing vegetation removed and worst after scalping. Mounding with herbicide application resulted in the lowest bulk density, best seedling growth, and increased water availability. Mounding may be a viable site preparation method in the Inland Northwest on less productive sites that have severe competition. Scalping, especially when competition was not a problem, generally did not produce favorable seedling growth responses. Scalping may also reduce longer term seedling growth by removing surface organic matter. West. J. Appl. For. 12(3):81-88.

Allelopathic potential of Verbesina encelioides root leachate in soil

2000 ◽  
Vol 77 (10) ◽  
pp. 1419-1424 ◽  
Author(s):  
Inderjit ◽  
Chikako Asakawa ◽  
KMM Dakshini
Keyword(s):  
Seedling Growth ◽  
High Performance ◽  
N Fertilization ◽  
Growth Responses ◽  
Crop Species ◽  
Allelopathic Potential ◽  
Perennial Weed ◽  
Full Strength ◽  
Verbesina Encelioides ◽  
Radish Seedlings

Verbesina encelioides (Cav.) Benth. & Hook. F. ex. A. Gray (Asteraceae) is a perennial weed that interferes with the growth and establishment of crop species in semiarid regions of India. The present research was designed to understand the probable involvement of allelopathy in its interference mechanism. We studied the effect of soils amended with different dilutions of V. encelioides root leachate (full strength and 1:2 and 1:4 (v/v) ratios of root leachate to water) on the growth of radish seedlings (Raphanus sativus L.). Soils that were not amended were used as controls. We also investigated the influence of different levels of N fertilization (1, 5, and 10 mM) on the modification of the allelopathic potential of amended soils, in terms of their effect on soil total phenolics and radish seedling growth. The addition of both full strength and 1:2 dilution of V. encelioides root leachate resulted in significant (P < 0.05) suppression of root (-25.7 and -17.2%, respectively) and shoot (-21.3 and -13.8%, respectively) growth of radish seedlings. The total level of phenolics in soil amended with full-strength (8.53 ± 0.55 µg/g), 1:2 dilution (5.43 ± 0.4 µg/g), and 1:4 dilution (4.17 ± 0.36 µg/g) was significantly (P < 0.05) higher compared with that of control (2.98 ± 0.47 µg/g) soil. Although the different amounts of N fertilization in soil amended with V. encelioides root leachate could not counteract the probable allelopathic interference, we observed an increase in root growth of radish seedlings in soil amended with 10 mM N fertilization plus either a 1:2 dilution (+21.2%) or a 1:4 dilution (+36.5%) of root leachate. No significant differences in NO3- and NH4+ concentration were observed between control soil and soil amended with different amounts of root leachate and N fertlization. Since allelopathic activities include both inhibitory and stimulatory growth responses, the radish seedling growth responses to V. encelioides root leachate can be explained by allelopathy. High performance liquid chromatography data indicate qualitative and quantitative differences in phenolic peaks of both control and amended soil. Our research demonstrates the allelopathic potential of V. encelioides roots and the probable involvement of allelopathy in its interference success.

Colonization and growth promotion of outplanted spruce seedlings pre-inoculated with plant growth-promoting rhizobacteria in the greenhouse

2000 ◽  
Vol 30 (6) ◽  
pp. 845-854 ◽  
Author(s):  
Masahiro Shishido ◽  
Christopher P Chanway
Keyword(s):  
Plant Growth ◽  
Seedling Growth ◽  
Picea Glauca ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Population Declines ◽  
Growth Responses ◽  
Relative Growth Rates ◽  
Plant Growth Promoting ◽  
Growth Promoting

Seeds of two hybrid spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) ecotypes were inoculated with one of six plant growth-promoting rhizobacteria (PGPR) strains previously shown to be able to stimulate spruce growth in controlled environments. The resulting seedlings were grown in the greenhouse for 17 weeks before outplanting at four reforestation sites. Inoculation with five of the six strains caused significant seedling growth promotion in the greenhouse, which necessitated analysis of relative growth rates (RGR) to evaluate seedling performance in the field. Four months after outplanting, most strains enhanced spruce shoot or root RGRs in the field, but seedling growth responses were strain specific. For example, Pseudomonas strain Ss2-RN significantly increased both shoot and root RGRs by 10-234% at all sites, but increases of 28-70% were most common. In contrast, Bacillus strain S20-R was ineffective at all outplanting sites. In addition, seedlings inoculated with four of the six strains had significantly less shoot injury than control seedlings at all sites. Evaluation of root colonization by PGPR indicated that bacterial population declines were not related to spruce growth response variability in the field. Our results indicate that once plant growth promotion is induced in the greenhouse, seedling RGR can increase by more than 100% during the first growing season in the field. However RGR increases of 21-47% were more common and may be more representative of the magnitude of biomass increases that can result from PGPR inoculation.

scholarly journals High Pressure Sodium Irradiation and Infrared Radiation Accelerate Petunia Seedling Growth

1991 ◽  
Vol 116 (3) ◽  
pp. 435-438 ◽  
Author(s):  
David F. Graper ◽  
Will Healy
Keyword(s):  
High Pressure ◽  
Seedling Growth ◽  
Root Zone ◽  
Photon Flux ◽  
Growth Responses ◽  
Ambient Conditions ◽  
Fresh Weight ◽  
Photosynthetic Photon Flux ◽  
Ir Radiation ◽  
Relative Growth

The increase in photosynthetic photon flux (PPF) and plant temperature associated with supplemental high pressure sodium (HPS) irradiation were investigated during Petunia × hybrids Villm. `Red Flash' seedling development. Seedlings were treated for 14 days following emergence or 5 days after the first true leaf had expanded to 1 mm. Treatments consisted of continuous infrared (IR) radiation (Ambient + IR), ambient conditions with spill-over radiation from adjacent treatments (Ambient - IR), root zone heating to 19.5C (RZ Heat), continuous HPS irradiation at 167 μmol·s-1.m-2 PPF (HPS + IR) or continuous HPS irradiation at 167 μmol-1·m-2 PPF filtered through a water bath to remove IR (HPS - IR). Linear regression of natural log-transformed fresh weights indicated that increasing ambient PPF 53% and elevating plant temperature 4.3C (HPS + IR) increased seedling relative growth rate (RGR) by 45% compared with the control (Ambient - IR). Elevating plant temperature with + IR by 4.8C without supplementing PPF (Ambient + IR) increased RGR by 31% but failed to increase fresh weight (FW) above controls and resulted in etiolated plants that were unsuitable for transplanting. Once plants were removed from supplemental treatment and returned to ambient conditions, RGR for all treatments was similar. The increased FW promoted by IR and HPS treatments was maintained for up to 7 days after treatment. Therefore, the increased seedling growth responses observed with HPS treatment were due primarily to an increase in RGR during HPS treatment that is not sustained beyond treatment.

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