Developmental studies on Euphorbia esula. The influence of the nitrogen supply on the correlative inhibition of root bud activity

1972 ◽  
Vol 50 (5) ◽  
pp. 949-956 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Nitrogen Supply ◽  
Euphorbia Esula ◽  
Nitrogen Level ◽  
Developmental Studies ◽  
Subsequent Increase ◽  
Lateral Buds ◽  
Lateral Shoots ◽  
Correlative Inhibition ◽  
Low Nitrogen

When seedlings of leafy spurge (Euphorbia esula L.) were grown at a low nitrogen level (10.5 ppm) the growth of the lateral buds on the shoot was completely arrested by apical dominance while the buds on the roots, although also inhibited, showed considerably greater activity. At a higher nitrogen level (210 ppm) apical dominance was markedly reduced but the resulting outgrowth of the lateral buds increased the inhibiting capacity of the shoot, limiting root bud response. When the main shoot was decapitated the degree to which root bud growth was suppressed by a given number of lateral shoots was inversely related to the nitrogen supply. Inhibition of the root buds by the lateral shoots could be significantly reduced by growing the plants initially at a low nitrogen level so that growth of the lateral buds was arrested. A subsequent increase in the nitrogen supply strongly promoted the growth of the roots buds, some of which were sufficiently released from inhibition to emerge as leafy shoots.

scholarly journals The Nature of Shoot Dominance in White Yam Tubers (Dioscorea rotundata Poir)

1969 ◽  
Vol 68 (4) ◽  
pp. 335-340
Author(s):  
Osi Mozie
Keyword(s):  
Apical Dominance ◽  
Distal Region ◽  
Proximal Region ◽  
Basal Region ◽  
Middle Region ◽  
Ambient Conditions ◽  
Dioscorea Rotundata ◽  
Lateral Buds ◽  
Lateral Shoots ◽  
White Yam

The nature of shoot dominance in white yam tubers (Dioscorea rotundata Poir) was studied under ambient conditions in the conventional yam storage barn. Whole tubers sprouted only at the proximal ends (i.e. the morphological bases). The single basal shoot formed per sprouting whole tuber inhibited the formation of lateral shoots along the tuber axis. Separating the basal end by sectioning the tuber into three regions namely "head" (i.e. basal or proximal region), middle region and "tail" (i.e. apical or distal region), appeared to stimulate the formation of lateral shoots on the surfaces of the tuber pieces below the basal region. Separating the basal region from the entire tuber by sectioning appeared to remove the stress under which the lateral buds had existed in the intact tuber. This response indicated a strong "basal dominance" of basal shoots in sprouting intact or whole yam tubers. The physiology of shoot dominance in whole yam tubers could be described as "basal dominance" rather than "apical dominance", since in sprouting intact or whole tuber it is the basal shoot (i.e. shoot of the morphological base or proximal end) that inhibits the development of lateral shoots along the tuber axis.

scholarly journals The role of specific plant organs and polar auxin transport in correlative inhibition of leafy spurge (Euphorbia esula) root buds

1998 ◽  
Vol 76 (7) ◽  
pp. 1227-1231 ◽  
Author(s):  
David P Horvath
Keyword(s):  
Apical Dominance ◽  
Auxin Transport ◽  
Leafy Spurge ◽  
Polar Auxin Transport ◽  
Euphorbia Esula ◽  
Transport Inhibitor ◽  
Correlative Inhibition ◽  
Auxin Transport Inhibitor ◽  
Bud Growth ◽  
Root Buds

Localization of the source of the signal(s) controlling correlative inhibition of leafy spurge root buds (underground adventitious shoot buds located on the lateral roots) was studied by sequential removal of various plant organs. It was determined that full correlative inhibition of root buds was lost only after excision of all aerial tissue from the plant, or after excision of all aerial tissue except the stem. If mature leaves or growing axillary buds (or both) were left intact, no growth of root buds was observed. The synthetic auxin, alpha-NAA, prevented release of apical dominance and subsequent outgrowth of stem and crown buds when applied to the cut end of the stem or crown. Exogenous application of NAA to either the stem or the crown had little effect on root bud growth. Application of the auxin transport inhibitor NPA around the base of the crown had no effect on root bud quiescence. These data are not consistent with the previous studies (Weed Sci. 35: 155-159 (1987)) that indicate a role for auxin in maintenance of correlative inhibition of root bud growth in leafy spurge. The results of auxin transport inhibitor studies presented here suggest that correlative inhibition of root bud growth does not rely on the classic polar auxin transport system.Nomenclature: leafy spurge, Euphorbia esula L. #3 EPHES; NAA, naphthalene acetic acid; NPA, N-1-naphthylphthalamic acid; TIBA, 2,3,5-triiodobenzoic acid.Key words: root buds, apical dominance, auxin, NPA.

Studies on bud development in the rhizome of Agropyron repens. II. The effect of the nitrogen supply

1972 ◽  
Vol 50 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Dry Weight ◽  
Nitrogen Supply ◽  
Parent Plant ◽  
Bud Development ◽  
Apical Buds ◽  
Rooting Medium ◽  
Correlative Inhibition ◽  
Bud Growth ◽  
Low Nitrogen ◽  
Agropyron Repens

Bud growth on isolated rhizomes of Agropyron repens showed a basipetal gradient of decreasing activity and was strongly inhibited at the basal nodes. This evident polarity was correlated with a gradient of decreasing nitrogen content at successively older nodes and with an apparent translocation of nitrogen from the basal to the apical nodes. Isolating the buds from one another reduced growth of the apical buds and prolonged the growth of buds at the basal nodes so that the polarity of bud growth, although still apparent, was much reduced.Supplying nitrogen as NH4NO3 through the cut end of rhizomes still attached to the parent plant caused apical buds to develop as shoots instead of rhizomes. Increasing the nitrogen supply to the rooting medium extended this response to buds at older nodes, restricting rhizome production to basal buds whose growth was inhibited in low nitrogen rhizomes.Buds developing as shoots had a considerably higher total nitrogen and moisture content and a lower dry weight than buds developing as rhizomes.The results emphasized the importance of the nitrogen supply not only in determining the polarity of bud growth and the degree of correlative inhibition, but also as a morphogenetic factor controlling bud development.

Nutritional control of the correlative inhibition between lateral shoots in the flax seedling (Linum usitatissimum)

1968 ◽  
Vol 46 (2) ◽  
pp. 147-155 ◽  
Author(s):  
G. I. McIntyre
Keyword(s):  
Linum Usitatissimum ◽  
Cotyledonary Node ◽  
Nutrient Supply ◽  
Mineral Nutrients ◽  
Nitrogen Supply ◽  
The Other ◽  
Sand Culture ◽  
Mineral Nutrient ◽  
Lateral Shoots ◽  
Correlative Inhibition

When the epicotyl of the flax seedling is decapitated one of the two shoots produced at the cotyledonary node tends to inhibit and may completely suppress the growth of the other. By growing the seedlings in sand culture with a controlled mineral nutrient supply it was shown that (a) the inhibiting influence of the dominant shoot was inversely related to the nitrogen level; (b) the inhibited shoot could be released from inhibition by increasing the nitrogen supply; (c) the removal of the dominant shoot was followed within 12 h by an increase in the total nitrogen content of the inhibited shoot; (d) a similar control of inhibition could be obtained by varying the phosphorus supply. These results are consistent with the hypothesis that this form of correlative inhibition is due primarily to competition between the shoots for a limited mineral nutrient supply.When one of the cotyledons was either covered or removed its axillary bud was inhibited by the shoot in the axil of the untreated cotyledon. The degree of inhibition was inversely related to the nitrogen supply. It is suggested as a working hypothesis that the cotyledons provide a factor(s) which promotes the growth of their axillary buds and thus determines their ability to compete for mineral nutrients.

Studies on the growth and development of the rhizome and lateral rhizome buds in Elytrigia repens: some effects of parent shoot excision

1998 ◽  
Vol 76 (5) ◽  
pp. 769-776 ◽  
Author(s):  
G I McIntyre ◽  
A J Cessna
Keyword(s):  
Apical Dominance ◽  
Water Pressure ◽  
C:N Ratio ◽  
Dry Weight ◽  
Nitrate Content ◽  
Total N ◽  
Lateral Buds ◽  
Elytrigia Repens ◽  
Correlative Inhibition ◽  
Rhizome Buds

In experiments conducted under controlled conditions, excision of the shoot of Elytrigia repens (L.) Nevski increased the rate of rhizome elongation and promoted the growth of the lateral rhizome buds. Measurements with a transducer showed that the long-term growth response of the rhizome to shoot excision (4-6 days) was preceded by an immediate but transient (10 min) increase in growth rate. These various responses were associated with the occurrence of guttation from the rhizome apex, increases in the water content of the rhizome apex and lateral buds, and a 62% increase in rhizome water (pressure) potential. Parent shoot excision also induced a transition from rhizome to shoot development at the rhizome apex and caused lateral buds to develop as shoots instead of rhizomes when released from apical dominance. These developmental responses were associated with reductions in the dry weight of the rhizome apex and lateral buds and increases in the total N, amino-N, and nitrate content of the rhizome apex when expressed on a dry weight basis. These results provide evidence that, in E. repens, competition for water by the parent shoot may limit rhizome growth and contribute to the correlative inhibition of the lateral buds. They are also consistent with previous evidence that the C:N ratio may be an important morphogenetic factor in the mechanism controlling the path of bud and rhizome development.Key words: Elytrigia repens, water, nitrogen, rhizome, apical dominance.

Apical dominance in the rhizome of Agropyron repens. Some factors affecting the degree of dominance in isolated rhizomes

1971 ◽  
Vol 49 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Soluble Nitrogen ◽  
Small Reduction ◽  
High Nitrogen ◽  
Factors Affecting ◽  
Lateral Buds ◽  
Degree Of Dominance ◽  
High Nitrogen Level ◽  
Low Nitrogen ◽  
Agropyron Repens

A study of apical dominance in isolated rhizomes of Agropyron repens L. Beauv. showed that increasing the length of the rhizome significantly reduced the degree of dominance only in rhizomes from plants grown at a high nitrogen level (210 ppm). Exposing the rhizomes to light also reduced dominance more effectively in high-nitrogen rhizomes but the response of rhizomes from low-nitrogen plants was greatly increased by supplying water through the end of the rhizome. Further experiments with low-nitrogen rhizomes showed that buds could be released from apical dominance by treatment with kinetin. When isolated from the plant the buds showed a significant increase in length after 24 h and an associated increase in moisture and insoluble nitrogen content. Soluble nitrogen and carbohydrate increased concurrently during the next 24 h. Rhizomes kept in darkness showed a small reduction of bud inhibition when water was supplied through the cut end; NH4NO3 solution had a greater effect, while solutions in which both nitrogen and carbohydrate (as sucrose) were supplied resulted in the almost complete elimination of apical dominance.The results suggest that apical dominance in isolated, low-nitrogen rhizomes was due mainly to competition between the apex and the lateral buds for water, nitrogen, and carbohydrate.

DEVELOPMENTAL STUDIES ON EUPHORBIA ESULA L.: SOME EFFECTS OF THE NITROGEN SUPPLY ON THE GROWTH AND DEVELOPMENT OF THE SEEDLING

1967 ◽  
Vol 45 (7) ◽  
pp. 975-984 ◽  
Author(s):  
G. I. McIntyre ◽  
M. V. S. Raju
Keyword(s):  
Root System ◽  
Growth And Development ◽  
Nitrogen Supply ◽  
Growth Potential ◽  
Euphorbia Esula ◽  
Nitrogen Level ◽  
Sand Culture ◽  
Shoot Height ◽  
Nitrogen Levels ◽  
Stage Of Development

The influence of the nitrogen supply on the growth and development of Euphorbia esula L. was investigated by growing seedlings in sand culture at nitrogen levels of 105 p.p.m. (later increased to 210 p.p.m.), 10.5 p.p.m. and 2.1 p.p.m. Shoot height and dry weight and the shoot/root ratio were much reduced by nitrogen deficiency and the outgrowth of lateral buds was completely suppressed at the lowest nitrogen level. Root development proved very responsive. The "heterorhizic" pattern of long and short roots of differing growth potential described from field observations was much less evident under the experimental conditions. Long roots were more numerous and were produced at an earlier stage of development than is usual in the field. These differences increased markedly with the nitrogen supply. The number of lateral roots (of both types) per unit length of the parent roots and the number of shoot buds on the root system were both considerably greater at the higher nitrogen levels. The increase in shoot bud production, however, could be largely attributed to associated effects on the size and mode of development of the root system. Regrowth from buds on the roots, induced by shoot removal, was extremely vigorous in the seedlings treated with high nitrogen but was almost completely suppressed at the lowest nitrogen level.

Studies on bud development in the rhizome of Agropyron repens. 1. The influence of temperature, light intensity, and bud position on the pattern of development

1970 ◽  
Vol 48 (11) ◽  
pp. 1903-1909 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Light Intensity ◽  
Environmental Conditions ◽  
Shoot Formation ◽  
Nitrogen Level ◽  
Influence Of Temperature ◽  
Bud Development ◽  
Lateral Buds ◽  
Bud Position ◽  
Low Nitrogen ◽  
Agropyron Repens

When plants of Agropyron repens L. Beauv. are grown at a low nitrogen level, decapitation of the rhizomes releases the lateral buds from inhibition and results in a well-marked polarity of bud development. This polarity is typically characterized by the restriction of shoot development to the bud nearest the apical end of the rhizome, the production of rhizomes from buds at a greater distance from the apex, and a tendency for the buds at the basal nodes to remain inhibited.It was shown that this pattern of bud development is readily affected by environmental conditions. Increasing the temperature from 15° to 25 °C caused a marked increase in shoot formation at the expense of rhizome production and a small increase in the number of dormant buds. Reducing the light intensity had a similar but much more pronounced effect. The position of the buds in relation to the cut end of the rhizome was relatively less important as a morphogenetic factor than their position on the intact plant.As a working hypothesis, based on previous results, it is suggested that a gradient in the C/N ratio might account for the observed polarity of bud development.

The correlative inhibition of bud and shoot growth in flax. Anatomical changes associated with the release of lateral buds from inhibition

1974 ◽  
Vol 52 (11) ◽  
pp. 2269-2275 ◽  
Author(s):  
Gordon I. McIntyre ◽  
Shirley D. Larmour
Keyword(s):  
Apical Dominance ◽  
Shoot Growth ◽  
Vascular Tissue ◽  
Sand Culture ◽  
Quiescent Center ◽  
Staining Reaction ◽  
Linum Usitatissimum L ◽  
N Supply ◽  
Lateral Buds ◽  
Correlative Inhibition

Seedlings of flax (Linum usitatissimum L.) were grown in sand culture under controlled conditions and the bud at node 3 was released from apical dominance by increasing the concentration of N in the nutrient solution. Within 24 h of increasing the N supply the number of mitoses per bud had markedly increased and within 48 h the length of the bud was significantly greater than the controls. A distinctive group of cells (the "quiescent center"), characterized by enlarged nuclei with a reduced Feulgen staining reaction, was present at the apex of all inhibited low-N buds but rapidly disappeared when the buds were released from inhibition. Of the buds examined 48 h after the N supply was increased, about 50% had no xylem in the bud trace; the rest had only a single xylem strand and none had established a connection with the stele of the parent stem. Buds examined after 72 h showed a marked increase in the number of xylem strands, but more than 75% of these buds still lacked a complete xylem connection with the vascular tissue of the parent shoot.These results support the hypothesis that the release of lateral buds from apical dominance is not dependent on the prior strengthening of the xylem connections and that associated changes in vascular tissue development are the consequence rather than the cause of the release of the bud from inhibition.

scholarly journals Morphological and physiological plasticity response to low nitrogen stress in black cottonwood (Populus deltoides Marsh.)

2021 ◽  
Author(s):  
Cun Chen ◽  
Yanguang Chu ◽  
Qinjun Huang ◽  
Changjun Ding ◽  
Weixi Zhang ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Nitrogen Use Efficiency ◽  
Root Biomass ◽  
Populus Deltoides ◽  
Leaf Traits ◽  
Nitrogen Level ◽  
Nitrogen Use ◽  
Use Efficiency ◽  
Normal Nitrogen ◽  
Low Nitrogen

AbstractIt is important to evaluate nitrogen use efficiency and nitrogen tolerance of trees in order to improve their productivity. In this study, both were evaluated for 338 Populus deltoides genotypes from six provenances. The plants were cultured under normal nitrogen (750 μM NH4NO3) and low nitrogen (5 μM NH4NO3) conditions for 3 months. Growth, chlorophyll content and glutamine synthetase activity of each genotype were measured. Under low nitrogen, heights, ground diameter, leaf area, leaf and root biomass, and chlorophyll contents were significantly lower than those under normal nitrogen level. Correlation analysis showed that nutrient distribution changed under different nitrogen treatments. There was a negative correlation between leaf traits and root biomass under normal nitrogen level, however, the correlation became positive in low nitrogen treatment. Moreover, with the decrease of nitrogen level, the negative correlation between leaf morphology and chlorophyll levels became weakened. The growth of the genotypes under the two treatments was evaluated by combining principal component analysis with a fuzzy mathematical membership function; the results showed that leaf traits accounted for a large proportion of the variation in the evaluation model. According to the results of comprehensive evaluation of plants under the two treatments, the 338 P. deltoides genotypes could be divided into nine categories, with wide genotypic diversity in nitrogen use efficiency and low nitrogen tolerance. As a result, 26 N-efficient genotypes and 24 N-inefficient genotypes were selected. By comparative analysis of their morphological and physiological traits under the two treatments, leaf traits could be significant indicators for nitrogen use efficiency and nitrogen tolerance, which is of considerable significance for breeding poplar varieties with high nitrogen use efficiencies.

Sign in / Sign up

Export Citation Format

Share Document