Growth of maize coleoptiles in the presence of natural and synthetic growth regulators. Growth correlations

The effect of natural (IAA, FC, ABA) and synthetic (2,4-D) growth substances on the increase of the fresh weight of maize coleoptile segments and change of the pH of the incubation medium, accepted here as criteria of maize coleoptile growth, was studied. The growth of maize coleoptiles depended on the concentration of the growth substances, as well as, on the composition of the incubation medium. The highest stimulation of coleoptile growth was seen with FC at a concentration of 10-4M, whereas ABA at 10-3 M gave the highest inhibition of maize coleoptile fresh weight increase and caused alkalization of the medium. The presence of K+ ions in the incubation medium enhanced the stimulatory effect of IAA and FC on the increase of the coleoptile fresh weight, whereas the presence of these ions and phosphate buffer abolished the growth-promoting effect of IAA and FC. The best correlation of the "fresh weight" and "pH" effects was found in the case of the growth of maize coleoptiles in the presence of FC (rxy = 0.67). The inhibition of maize coleoptile growth in the presence of high concentrations of IAA can be explained by the destructive effect of natural auxin at these concentrations on the integrity of mitochondrial membranes, and therefore on the normal functioning of mitochondria.

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THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: V. A PRELIMINARY EXAMINATION OF THE LEVEL OF FREE ENDOGENOUS INDOLEACETIC ACID IN RUSTED AND MILDEWED CEREAL LEAVES AND THEIR ABILITY TO DECARBOXYLATE EXOGENOUSLY SUPPLIED RADIOACTIVE INDOLEACETIC ACID

Canadian Journal of Botany ◽

10.1139/b58-001 ◽

1958 ◽

Vol 36 (1) ◽

pp. 1-16 ◽

Cited By ~ 67

Author(s):

Michael Shaw ◽

A. R. Hawkins

Keyword(s):

Oxidase Activity ◽

Indoleacetic Acid ◽

Sharp Decrease ◽

Inhibiting Activity ◽

Growth Substances ◽

Fresh Weight ◽

Avena Coleoptile ◽

Preliminary Examination ◽

Growth Promoting ◽

Host Parasite

The growth substances were extracted with cold alcohol from the first leaves of uninfected, rusted (wheat), and mildewed (barley) cereal seedlings. The acid ether fractions were chromatographed on paper and the chromatograms were cut into sections which were assayed for growth promoting or inhibiting activity in the Avena coleoptile straight growth test. The estimated, free, endogenous indoleacetic acid content of uninfected leaves ranged from 0.5 to 3.2 μg. per kilogram fresh weight. In the early stages of infection this decreased, but increased again to from 5 to about 10 μg. per kilogram fresh weight by the 10th day after the inoculation of susceptible hosts. Indoleacetic acid was not detected in ungerminated uredospores of stem rust (race 15B), but two other growth promoting substances appeared to be present.Leaf disks were incubated with radioactive indoleacetic acid (as —C14OOK) and the radioactivity released as C14O2 was measured. The ability of the tissue to decarboxylate the indoleacetate (‘oxidase’ activity) increased sharply, sometimes to as much as 1000%, in the first 3 days after inoculation. With susceptible hosts, this increase was followed by an almost equally sharp decrease to less than 50% of the values for uninfected tissue. With infected, resistant tissue, the secondary decrease in ‘oxidase’ activity was delayed and less pronounced.The results are discussed and a working hypothesis suggested with respect to the relation between susceptibility or resistance and the auxin balance.

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A Plant Growth-Promoting Bacterium That Decreases Nickel Toxicity in Seedlings

Applied and Environmental Microbiology ◽

10.1128/aem.64.10.3663-3668.1998 ◽

1998 ◽

Vol 64 (10) ◽

pp. 3663-3668 ◽

Cited By ~ 314

Author(s):

Genrich I. Burd ◽

D. George Dixon ◽

Bernard R. Glick

Keyword(s):

Plant Growth ◽

Dry Weight ◽

Nickel Chloride ◽

Promoting Effect ◽

Nickel Toxicity ◽

Nickel Uptake ◽

Plant Growth Promoting ◽

Growth Promoting ◽

High Concentrations ◽

Kluyvera Ascorbata

ABSTRACT A plant growth-promoting bacterium, Kluyvera ascorbataSUD165, that contained high levels of heavy metals was isolated from soil collected near Sudbury, Ontario, Canada. The bacterium was resistant to the toxic effects of Ni2+, Pb2+, Zn2+, and CrO4 −, produced a siderophore(s), and displayed 1-aminocyclopropane-1-carboxylic acid deaminase activity. Canola seeds inoculated with this bacterium and then grown under gnotobiotic conditions in the presence of high concentrations of nickel chloride were partially protected against nickel toxicity. In addition, protection by the bacterium against nickel toxicity was evident in pot experiments with canola and tomato seeds. The presence of K. ascorbata SUD165 had no measurable influence on the amount of nickel accumulated per milligram (dry weight) of either roots or shoots of canola plants. Therefore, the bacterial plant growth-promoting effect in the presence of nickel was probably not attributable to the reduction of nickel uptake by seedlings. Rather, it may reflect the ability of the bacterium to lower the level of stress ethylene induced by the nickel.

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Xyloglucan- and cello-oligosaccharides: Antagonists of the growth-promoting effect of H+

Physiologia Plantarum ◽

10.1034/j.1399-3054.1990.800117.x ◽

1990 ◽

Vol 80 (1) ◽

pp. 109-113 ◽

Cited By ~ 2

Author(s):

Ester P. Lorences ◽

Gordon J. McDougall ◽

Stephen C. Fry

Keyword(s):

Promoting Effect ◽

Growth Promoting

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IS THE GROWTH-PROMOTING EFFECT OF ANTIBIOTICS CONNECTED WITH THYROID FUNCTION?

Acta Endocrinologica ◽

10.1530/acta.0.0160365 ◽

1954 ◽

Vol 16 (4) ◽

pp. 365-368 ◽

Cited By ~ 4

Author(s):

Antti Telkkä ◽

A. N. Kuusisto

Keyword(s):

Thyroid Function ◽

Promoting Effect ◽

Growth Promoting

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Quantitative Relationship between Stimulus and Response in the Growth-Promoting Effect of Spirometra mansonoides Spargana on the Hypophysectomized Rat

Journal of Parasitology ◽

10.2307/3277738 ◽

1970 ◽

Vol 56 (4) ◽

pp. 840 ◽

Cited By ~ 8

Author(s):

Justus F. Mueller

Keyword(s):

Quantitative Relationship ◽

Promoting Effect ◽

Growth Promoting

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Effects of follicular fluids on the growth of porcine preantral follicle and oocyte

Zygote ◽

10.1017/s0967199408004711 ◽

2008 ◽

Vol 16 (3) ◽

pp. 239-247 ◽

Cited By ~ 8

Author(s):

T. Metoki ◽

H. Iwata ◽

M. Itoh ◽

M. Kasai ◽

A. Takajyo ◽

...

Keyword(s):

Calf Serum ◽

Follicle Development ◽

Preantral Follicle ◽

Promoting Effect ◽

Oocyte Growth ◽

Preantral Follicles ◽

Molecular Weights ◽

Heat Treated ◽

Growth Promoting ◽

Follicular Fluids

SummaryWe examined the effect of supplementing the culture medium with follicular fluid (FF) on the growth of porcine preantral follicles and oocytes. Firstly, preantral follicles were retrieved from ovaries and then FF was collected from all antral follicles that were 2–7 mm in diameter (AFF), which included large follicles of 4–7 mm in diameter (LFF) and small follicles of 2–3 mm in diameter (SFF). When preantral follicles with a diameter of 250 μm were cultured in medium containing AFF, the growth of follicles and oocytes was greater than when follicles were cultured in medium containing fetal calf serum (FCS). When this growth-promoting effect in AFF was compared for LFF and SFF, the LFF were shown to be significantly more effective than SFF. This LFF effect was lost, however, when the concentration of LFF in the medium was decreased from 5% to 0.5% or when LFF were heat treated (60 °C for 30 min) or trypsin was added. In contrast, a decrease in SFF concentration from 5% to 0.5% and heat treatment of the SFF enhanced preantral follicle growth. Furthermore, proteins obtained from LFF that had molecular weights greater than 10 kDa (LFF > 10 kDa) had similar, but relatively reduced, growth-promoting properties. The remaining three LFF protein fractions (<10 kDa or <100 kDa or >100 kDa), however, did not have these growth-promoting properties. In conclusion, the supplementation of medium with LFF, rather than serum, enhanced preantral follicle and oocyte growth. Factors that enhanced follicle development in LFF and factors that suppressed follicle development in SFF were proteins and these LFF factors ranged in size from 10 kDa to over 100 kDa.

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