scholarly journals MOVEMENT OF SELECTED GROWTH-REGULATING CHEMICALS IN ARTIFICIAL GROWING MEDIA

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 633e-633
Author(s):  
Kurt A. Schekel ◽  
Paul S. Kaczmarczyk

The presence of the growth regulators paclobutrazol and uniconazole in leachate or distribution through media consisting of various proportions of Douglas fir bark, sphagnum peat and perlite was evaluated. Distribution through a column 25 cm deep occurred rapidly and growth regulators were found in the leachate the first day after drench application when perlite was in the mix. Movement was limited to a maximum of the top 60% of the column in bark and peat mixes without perlite. Leachate was collected daily over a 12 day period after drenches were applied. Paclobutrazol and uniconazol showed similar distribution patterns in the media.

1999 ◽  
Vol 17 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Robert H. Stamps ◽  
Michael R. Evans

Abstract A comparison was made of Canadian sphagnum peat (SP) and Philippine coconut (Cocos nucifera L.) coir dust (CD) as growing media components for greenhouse production of Dracaena marginata Bak. and Spathiphyllum Schott ‘Petite’. Three soilless foliage plant growing mixes (Cornell, Hybrid, University of Florida #2 [UF-2]) were prepared using either SP or CD and pine bark (PB), vermiculite (V), and/or perlite (P) in the following ratios (% by vol): Cornell = 50 CD or SP:25 V:25 P, Hybrid = 40 CD or SP:30 V:30 PB, UF-2 = 50 CD or SP: 50 PB. Dracaena root growth was not affected by treatments but there were significant mix × media component interactions that affected plant top growth parameters. In general, the growth and quality of D. marginata were reduced by using CD in Cornell, had no effect in Hybrid, and increased in UF-2. S. ‘Petite’ grew equally well in all growing mixes regardless of whether CD or SP was used; however, plants grew more in Cornell and Hybrid than in UF-2. S. ‘Petite’ roots, which were infested with Cylindrocladium spathiphylli, had higher grades when grown in CD than when the media contained SP.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 436C-436
Author(s):  
Kimberly A. Klock

Ornamental horticulture industries have the opportunity to utilize compost products as components in growing media, but heterogeneity among compost products can cause unpredictability in the activity of some growth regulators when applied as a drenches to the growing medium. These experiments evaluated the effect of 0%, 30%, 60%, or 100% compost (by volume) in the medium on the efficacy of paclobutrazol applied as a drench on Impatiens wallerana Hook. In experiment 1, paclobutrazol was applied at active ingredient (a.i.) drench rates of 0, 0.016, 0.032, 0.06, or 0.125 mg/pot 16 days after transplanting impatiens `Accent Red'. In experiment 2, paclobutrazol was applied at a.i. drench rates of 0, 0.25, 0.50, 1.0, or 2.0 mg/pot 14 days after transplanting impatiens `Dazzler Punch'. In both experiments, final height and size were reduced by paclobutrazol treatments compared to untreated plants. In experiment 1, shoot dry mass of treated plants was on the average of 0.92 g less than untreated plants, while shoot dry mass, in experiment 2, did not show a significant difference between treated and untreated plants. In both experiments, final height, size and shoot dry mass were significantly different among the media, with the greatest growth in 100% compost.


1979 ◽  
Vol 57 (9) ◽  
pp. 1000-1007 ◽  
Author(s):  
George C. Carroll

Distribution patterns and total cell-volume estimates for needle microepiphytes are presented for three strata in the canopy of a single old-growth Douglas fir tree. Microbial cell volume was estimated by photographing transverse sections of needles, tracing microbial profiles on Mylar film, cutting out the tracings, and determining the pooled trace weights from various zones of each needle section. Microbial cells are concentrated in the midrib groove and over the stomatal zones of individual needles. Microbial cell volume on the upper needle surfaces increases during the 1st year and declines in subsequent years. Cell volumes on the lower needle surfaces increase from the 1st to the 3rd year and decrease from the 3rd to the 4th year. An increase in microbial cell volume occurs on both upper and lower surfaces from year 7 to year 8. Total microbial cell volume in relation to available needle surface area is greatest in the lower canopy and decreases with increasing height in the canopy. The total volume of microbial cells on needles was estimated to be 1093 cm3 for the entire tree.


2012 ◽  
Vol 81 (4) ◽  
pp. 199-221 ◽  
Author(s):  
Bert W. Hoeksema

A phylogenetically based comparative analysis of onshore-offshore distribution patterns of mushroom coral species (Scleractinia: Fungiidae) was made to reconstruct an evolutionary scenario for differentiation in fungiid shelf habitats. This phyloecological study integrates data on fungiid distribution patterns along environmental gradients on the Spermonde Shelf, SW Sulawesi, with a recently published phylogeny reconstruction of the Fungiidae. A mushroom coral fauna of 34 species was used to compare their distributions by use of 50-m2 belt quadrats in transects (1) from the mainland to the shelf edge, (2) around reefs with regard to predominant wind directions, and (3) over bathymetrical reef zones. Species association ordinations were made for each of the four shelf zones using both abundance and incidence data to examine whether closely related species cooccurred. Some closely related species or even sister species appeared to show very similar distribution patterns and to coexist in high abundances. These results indicate that there may not be community saturation and competitive exclusion among mushroom corals species, most of which are free-living. In reconstructions of fungiid habitat evolution, offshore reef slopes appear to be original (ancestral), whereas onshore habitats, shallow reef flats, and deep sandy reef bases seem to be derived. The latter is in contrast with an earlier hypothesis, in which deep sandy substrates were considered ancestral mushroom coral habitats.


HortScience ◽  
2017 ◽  
Vol 52 (12) ◽  
pp. 1692-1699 ◽  
Author(s):  
Patrick H. Kingston ◽  
Carolyn F. Scagel ◽  
David R. Bryla ◽  
Bernadine Strik

The purpose of the present study was to investigate the suitability of different soilless substrates for container production of highbush blueberry (Vaccinium sp.). Young plants of ‘Snowchaser’ blueberry were grown in 4.4-L pots filled with media containing 10% perlite and varying proportions of sphagnum moss, coconut (Cocos nucifera L.) coir, and douglas fir [Pseudotsuga menziesii Mirb. (Franco)] bark, as well as a commercially available mix of peatmoss, perlite, and other ingredients for comparison. Total plant dry weight (DW) was similar among the treatments at 72 days after transplanting, but at 128 days, total DW was nearly twice as much in the commercial mix and in media with ≥60% peat or coir than in media with ≥60% bark. Inadequate irrigation likely played a role in poor plant growth in bark. Bark had lower porosity and water holding capacity than peat, coir, or the commercial mix and, therefore, dried quickly between irrigations. Bark also reduced plant uptake efficiency of a number of nutrients, including N, P, K, S, Ca, Mg, Mn, B, Cu, and Zn. Uptake efficiency of P, K, and Mg also differed between plants grown in peat and coir, which in most cases was a function of the initial concentration of nutrients in the media. Before planting, peat had the highest concentration of Mg and Fe among the media, whereas coir had the highest concentration of P and K. Leachate pH was initially lowest with peat and highest with coir but was similar among each of the media treatments by the end of the study. Electrical conductivity (EC) of leachate never exceeded 0.84 dS·m−1 in any treatment. Overall, peat and coir appear to be good substrates for container production of highbush blueberry. Bark, on the other hand, was less suitable, particularly when it exceeded 30% of the total media composition.


2015 ◽  
Vol 3 (2) ◽  
pp. 72
Author(s):  
J.-Roger Bansimba Mukiese ◽  
Aimé Diamuini Ndofunsu ◽  
Freddy Bulubulu ◽  
Alexandre Mbaya Ntumbula ◽  
Sébastien Luyindula Ndiku

<p>Shiny dome-like structures measuring less than 1mm in length were excised aseptically from shoot tip buds of infected of two cassava (<em>Manihot esculenta</em> Crantz) local cultivars (Boma and Mpelo Nlongi) and cultivated <em>in vitro</em> in two types of media with different combination of growth hormone: Murashige and Skoog supplemented of sucrose (20 g/l), Naphtalenacetic acid (NAA, 10 μM), Ben-zylaminopurine (BAP, 0.66 μM) as well as Gibberellic acid (GA3, 0.1 μM) with 80 mg/l of Adenine sulphate and MS-free growth regulators. After four weeks, data were scored: 29.5% responding explant with callus formation and 20.5% responding explants to shoot development in the medium with growth regulators for the cultivar Boma whereas the cultivar Mpelo-Nlongi presented 5.7% and 25.7% respectively of callus formation and shoot development. The cultivar Boma presented a tendency more pronounced for the callus formation rather than with the shoot development contrary to the cultivar Mpelo-Nlongi. In regards of this experiment, it was shown that the media composition and genotype are essential factors, which influence in vitro growth, mainly the shoot development, in the culture of meristems for cassava local accessions.</p>


2020 ◽  
Vol 12 (15) ◽  
pp. 5992
Author(s):  
Antonios Chrysargyris ◽  
Panayiota Xylia ◽  
Gorkem Akinci ◽  
Konstantinos Moustakas ◽  
Nikolaos Tzortzakis

Significant quantities of paper waste (PW) have been accumulated in recent years and the reuse/recycling of PW is required due to environmental concerns. In the present study, printed PW was used as a peat (P) substitute in growing medium for the Brassica seedlings production, considering recycling, sustainable agriculture, and partly peat replacement. Seeds of cauliflower, broccoli, and cabbage were seeded in growing media made of 0–10–30–50% PW. The addition of PW improved the growing media pH and mineral content, reduced the media aeration, and affected seed emergence. The PW decreased plant growth and the effects were more pronounced at 50% PW. The PW ≥ 30% decreased stomatal conductance, while chlorophyll fluorescence and content of chlorophylls decreased with high PW ratio, negatively affecting the plant physiology. The PW decreased plant sodium and iron and increased potassium, calcium, magnesium, and copper content. The PW increased antioxidant activity to a certain degree for cauliflower and cabbage and resulted in no change for broccoli, while polyphenols increased in cabbage seedlings. The addition of PW did not cause cellular damage as both lipid peroxidation and hydrogen peroxide production remained at low levels, maintaining low levels on the antioxidant enzymes (catalase, superoxide dismutase, peroxidase) metabolism. The present study shows that low PW content can partially replace peat for Brassica seedling production under a sustainable agriculture and environmentally friendly scheme.


Zygote ◽  
1995 ◽  
Vol 3 (3) ◽  
pp. 207-217 ◽  
Author(s):  
B. Baccetti ◽  
A.G. Burrini ◽  
G. Collodel ◽  
C. Falugi ◽  
E. Moretti ◽  
...  

SummaryThe distribution of different classes of acetylcholine (ACh) receptor-like molecules in sperms of different invertebrate and vertebrate species is described. ACh receptor molecules belong to one of two classes: muscarinic receptors (mAChRs), associated with signal transduction mechanisms in the inner domain of the cell, and nicotinic receptors (nAChRs), capable of opening Na+ channels when activated by the ligand. Molecules immunologically related to mAChRs and to ACh can be identified by specific antibodies, and revealed by immunofluorescent or immunogold staining; the nicotinic receptor-like molecules are localised as curare-sensitive affinity sites for α-bungarotoxin. In all species studied, both classes of receptors were found, with a similar distribution. Muscarinic-like molecules were found mainly in the sperm head regions of most species; such a localisation may be correlated to a function in sperm–egg interaction, for instance in the regulation of the block to polyspermy. Nicotinic-like molecules are present mainly in the tail and in the post-acrosomal region of most animals, thus confirming their function in the regulation of sperm propulsion, but are also present at the acrosomal region of most species. The distribution patterns of the different classes of molecules indicate that both may be in sperm–egg interactions, in addition to their known function in the regulation of sperm propulsion.


1995 ◽  
Vol 25 (7) ◽  
pp. 1103-1112 ◽  
Author(s):  
Sylvie Richard ◽  
Sylvie Gauthier ◽  
Sylvie Laliberté

The search for the occurrence of somaclonal variation of in vitro shoots and acclimatized plants of a hybrid larch (Larix × urolepis Henry) clone was performed by the analysis of eight isozyme systems. Cultures were established from short shoot buds of mature material. The effects of growth regulators in the media, subculture intervals, and periods in culture were analyzed for in vitro shoots. Variability was found in in vitro shoots but appeared to be related to a physiological response to culture conditions. Once acclimatized, most tissuecultured plants expressed the same enzymatic patterns as those of control plants (stecklings and the ortet). The variations observed for some acclimatized plants were also observed in control plants and were not related to ontogenic stage. Results from the isoenzymatic systems studied showed that hybrid larch plants regenerated from tissue culture were not significantly different from stecklings and the ortet.


1970 ◽  
Vol 102 (10) ◽  
pp. 1258-1267 ◽  
Author(s):  
Susan B. McIver

AbstractThe type, number, and distribution of the antennal sense organs of female Culex territans Walker and Culex restuans (Theo.) were determined and compared to similar data on Culex pipiens L., Culex fatigans Wiedemann, and Culex tarsalis Coquillett. All types of sense organs have similar distribution patterns on the five species, but large differences in number occur. These differences are discussed with regard to the host preference of the mosquitoes.


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