Nodule-Like Structures Induced on the Roots of Rice Seedlings by Addition of the Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid

1993 ◽  
Vol 20 (6) ◽  
pp. 705 ◽  
Author(s):  
RW Ridge ◽  
KM Ride ◽  
BG Rolfe
Keyword(s):  
Early Stage ◽  
Lateral Roots ◽  
Rice Variety ◽  
Root Surface ◽  
Dichlorophenoxyacetic Acid ◽  
Internal Tissue ◽  
Rice Seedlings ◽  
Rice Varieties ◽  
Close Proximity ◽  
2,4 Dichlorophenoxyacetic Acid

Nodule-like structures were induced on rice varieties Calrose and Pelde using 2,4-dichlorophenoxyacetic acid (2,4-D) in a concentration range of 2.5 × 10-6 M to 1 × 10-5M. The nodule-like structures appeared to result from the fusion of multiple meristems induced in very close proximity to each other. The internal tissue differentiation of some of the nodule-like structures was found to be similar to that of both Parasponia nodules and some kinds of determinate legume nodules. These spheroid nodule-like structures, similar in external morphology to determinate legume nodules, showed no internal infection or colonisation by Rhizobium strain NGR 234 or the Azorhizobium strain ORS 571. However, on the rice variety Calrose, the strain ORS 571 sometimes colonised extensively the surface of the nodule- like structures, in comparison to levels found on emerging lateral roots and to the root surface of the same plants. The strain NGR 234 did not colonise the surface of the nodule-like structures. The synthetic phytohormone 2,4-D also induced a range of other phenomena, including various levels of fusion of primordia and structures with a callus-like surface instead of an epidermis, but with a differentiated internal anatomy. These experiments indicate that tissue development in some types of nodule is the result of a number of meristems fusing together at a single site, and at a very early stage in development.

scholarly journals Effect of salt stress on physiological response and leaf polyamine content in NERICA rice seedlings

2011 ◽  
Vol 57 (No. 12) ◽  
pp. 571-576 ◽  
Author(s):  
A. Yamamoto ◽  
H. Sawada ◽  
I.S. Shim ◽  
K. Usui ◽  
S. Fujihara
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Rice Variety ◽  
West African ◽  
Rice Seedlings ◽  
Rice Varieties ◽  
Stress Injury ◽  
African Rice ◽  
Polyamine Content ◽  
Vigorous Growth

NERICA is a new African rice variety, developed by the West African Rice Development Association (WARDA) in 1990s. NERICA rice shows both vigorous growth and tolerance of stressors such as drought and disease. The purpose of this study was to clarify the physiological and biochemical responses to salt stress of NERICA rice seedlings. The degree of growth inhibition caused by salt stress was small in NERICA rice varieties as compared with japonica Nipponbare. Na accumulation in leaf blades was high in salt-sensitive varieties. Accumulation of proline, a known compatible solute, was also induced by salt stress, especially in salt-sensitive varieties; it was thought that this accumulation was brought on salt-stress injury. The contents of polyamines, especially spermidine, were high in the pre-stressed leaf blades of NERICA rice seedlings. After the salt-stress treatment, the polyamine content of leaf blades differed with the degree of salt tolerance of the NERICA rice seedlings. These results suggested that the salt tolerance of NERICA rice seedlings might be associated not only with the regulation of Na absorption and translocation but also with their ability to maintain leaf polyamine levels under salt-stress conditions.  

Nodule-Like Structures Induced on the Roots of Wheat Seedlings by the Addition of the Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid and the Effects of Microorganisms

1992 ◽  
Vol 19 (5) ◽  
pp. 481 ◽  
Author(s):  
RW Ridge ◽  
GL Bender ◽  
BG Rolfe
Keyword(s):  
Internal Structure ◽  
Vascular Tissue ◽  
Vascular System ◽  
Lateral Roots ◽  
Growth Time ◽  
Dichlorophenoxyacetic Acid ◽  
Wheat Seedlings ◽  
Synthetic Auxin ◽  
Seedling Roots ◽  
2,4 Dichlorophenoxyacetic Acid

The addition of the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) at a concentration range of between 5 × 10-5 M and 1 × 10-6M caused nodule-like outgrowths on wheat seedling roots. Concentrations of 2,4-D greater than this range caused stunting and death, while concentrations less than 1 × 10-7 M had no obvious effect on plant growth. At the lower end of the concentration range, 2,4-D had a small inhibiting effect on seedling growth. Time-course studies on the development of the nodule-like outgrowths showed that they developed at the same rate as control lateral roots; there was regionality within the structure, and at least three cell types were present: a cell division zone, amyloplast-containing cells, and highly vacuolated cells. There was no organised vascular system similar to Rhizobium/legume symbiotic nodules, although vascular tissue was found to enter the nodule-like outgrowths. Different strains of Rhizobium, Azospirillurn, Agrobacterium and Escherichia coli were added separately with 2,4-D to the seedling roots, showing different effects on seedling health and on the growth and internal structure of the nodule-like outgrowths. Generally, bacteria caused a less-organised internal structure to the growths and earlier 'senescence'. Some bacteria also caused stunting and death of seedlings at concentrations of 2,4-D that would have no such effect alone. We conclude that these induced nodule-like outgrowths are modified lateral roots with carbon reserves (as starch in amyloplasts) similar to those found in the cortex of roots, and that microorganisms are able to modulate or interfere with the development of these outgrowths.

Glycaemic responses to glucose and rice in people of Chinese and European ethnicity

2020 ◽  
Author(s):  
M Kataoka ◽  
BJ Venn ◽  
SM Williams ◽  
Lisa Te Morenga ◽  
IM Heemels ◽  
...  
Keyword(s):  
Ethnic Differences ◽  
Rice Variety ◽  
Glycaemic Index ◽  
Activity Levels ◽  
Glycaemic Response ◽  
Rice Varieties ◽  
Adjusted Risk ◽  
Postprandial Glycaemia ◽  
Adjusted Risk Ratio ◽  
Glucose Curve

Aims: Diabetes rates are especially high in China. Risk of Type 2 diabetes increases with high intakes of white rice, a staple food of Chinese people. Ethnic differences in postprandial glycaemia have been reported. We compared glycaemic responses to glucose and five rice varieties in people of European and Chinese ethnicity and examined possible determinants of ethnic differences in postprandial glycaemia. Methods: Self-identified Chinese (n = 32) and European (n = 31) healthy volunteers attended on eight occasions for studies following ingestion of glucose and jasmine, basmati, brown, Doongara® and parboiled rice. In addition to measuring glycaemic response, we investigated physical activity levels, extent of chewing of rice and salivary α-amylase activity to determine whether these measures explained any differences in postprandial glycaemia. Results: Glycaemic response, measured by incremental area under the glucose curve, was over 60% greater for the five rice varieties (P < 0.001) and 39% greater for glucose (P < 0.004) amongst Chinese compared with Europeans. The calculated glycaemic index was approximately 20% greater for rice varieties other than basmati (P = 0.01 to 0.05). Ethnicity [adjusted risk ratio 1.4 (1.2-1.8) P < 0.001] and rice variety were the only important determinants of incremental area under the glucose curve. Conclusions: Glycaemic responses following ingestion of glucose and several rice varieties are appreciably greater in Chinese compared with Europeans, suggesting the need to review recommendations regarding dietary carbohydrate amongst rice-eating populations at high risk of diabetes. © 2012 Diabetes UK.

In Vitro Shoot Regeneration from Callus Derived from Marubakaido Apple Rootstock under Different Aluminium Concentrations

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 460e-460 ◽  
Author(s):  
Marisa F. de Oliveira ◽  
Gerson R. de L. Fortes ◽  
João B. da Silva
Keyword(s):  
Shoot Regeneration ◽  
Dichlorophenoxyacetic Acid ◽  
Apple Rootstock ◽  
Under Five ◽  
Significant Difference ◽  
Previously Treated ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
In Vitro Shoot Regeneration

The aim of this work was to evaluate the organogenesis of Marubakaido apple rootstock under different aluminium concentratons. The explants were calli derived from apple internodes treated with either 2,4-dichlorophenoxyacetic acid or pichloram at 0.5 and 1.0 μM and under five different aluminium concentrations (0, 5, 10, 15, 20 mg/L). These calli were then treated with aluminium at 0, 5, 10, 15, and 20 mg/L. It was observed shoot regeneration only for those calli previously treated with pichloram. There were no significant difference among the aluminium concentrations.

Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 483a-483
Author(s):  
Roy N. Keys ◽  
Dennis T. Ray ◽  
David A. Dierig
Keyword(s):  
Field Experiments ◽  
Reproductive Mode ◽  
Dichlorophenoxyacetic Acid ◽  
Initial Field ◽  
Breeding Lines ◽  
Reproductive Modes ◽  
Desert Southwest ◽  
2,4 Dichlorophenoxyacetic Acid

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.

The role of a metabolic intermediate in the biodegradation of inhibitory substrates

1997 ◽  
Vol 36 (10) ◽  
pp. 27-36 ◽  
Author(s):  
P. Mungkarndee ◽  
S. M. Rao Bhamidimarri ◽  
A. J. Mawson ◽  
R. Chong
Keyword(s):  
The Other ◽  
Metabolic Product ◽  
Dichlorophenoxyacetic Acid ◽  
Mutual Inhibition ◽  
Metabolic Intermediate ◽  
Batch Cultures ◽  
Ortho Cresol ◽  
2,4 Dichlorophenoxyacetic Acid

Biodegradation of the mixed inhibitory substrates, 2,4-dichlorophenoxyacetic acid (2,4-D) and para-chloro-ortho-cresol (PCOC) was studied in aerobic batch cultures. Each substrate added beyond certain concentrations inhibited the degradation of the other. This mutual inhibition was found to be enhanced by 2,4-dichlorophenol (2,4-DCP) which is an intermediate metabolic product of 2,4-D. When 2,4-DCP accumulated to approximatelY 40 mg/l degradation of all compounds in the mixed 2,4-D and PCOC substrate system was completely inhibited. The degradation of 2,4-D and PCOC individually was also found to be inhibited by elevated concentrations of 2,4-DCP added externally, while PCOC inhibited the utilization of the intermediate.

2,4-dichlorophenoxyacetic acid through lactation induces astrogliosis in rat brain

1997 ◽  
Vol 30 (3) ◽  
pp. 175-185 ◽  
Author(s):  
A. Brusco ◽  
J. Pecci Saavedra ◽  
G. García ◽  
P. Tagliaferro ◽  
A. M. Evangelista de Duffard ◽  
...  
Keyword(s):  
Rat Brain ◽  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid
Sign in / Sign up

Export Citation Format

Share Document