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.

The correlative inhibition of bud and shoot growth in flax (Linum usitatissimum). Some factors affecting the pattern and degree of inhibition

1975 ◽  
Vol 53 (4) ◽  
pp. 390-402 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Shoot Apex ◽  
Linum Usitatissimum ◽  
Nitrogen Nutrition ◽  
Growth Potential ◽  
Sand Culture ◽  
Factors Affecting ◽  
Linum Usitatissimum L ◽  
N Supply ◽  
Lateral Buds ◽  
Correlative Inhibition

When flax (Linum usitatissimum L.) seedlings were grown in sand culture under controlled conditions, growth of the lateral buds and their release from apical dominance showed a positive correlation with the N supply. The response of the buds was related to their position on the shoot and a well-defined gradient of bud growth potential was apparent at all N levels. Removal of the basal buds, which have the highest growth potential, induced the outgrowth of buds at higher nodes and increased the growth of the main shoot apex. Similar effects were produced by increasing the N supply to the intact plant.Providing N only as nitrate inhibited apical growth and caused severe leaf necrosis. These effects were due to zinc deficiency and could be prevented or significantly reduced not only by increasing the zinc supply but also by reducing the N level, providing some NH4-N, reducing the light intensity, or increasing the depth of planting. They could also be prevented by removal of the lateral buds at the basal nodes, thus indicating that the shoot apex and lateral buds may compete for the limited zinc supply. The obviously complex relationship between zinc and nitrogen nutrition in this species requires further investigation.

Studies on the growth and development of Agropyron repens: interacting effects of humidity, calcium, and nitrogen on growth of the rhizome apex and lateral buds

1987 ◽  
Vol 65 (7) ◽  
pp. 1427-1432 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Apical Dominance ◽  
Water Status ◽  
Dry Weight ◽  
Apical Growth ◽  
High Humidity ◽  
N Supply ◽  
Lateral Buds ◽  
Low Humidity ◽  
Bud Growth ◽  
Agropyron Repens

A previous investigation of apical dominance in the rhizome of Agropyron repens showed that keeping the rhizome in a high humidity promoted the outgrowth of the lateral buds but strongly inhibited the growth of the rhizome apex. A study of these related responses demonstrated that the inhibition of apical growth was not prevented by excision of the lateral buds and was also induced when only the apex of the rhizome received the high humidity treatment. The necrotic lesions that developed in the arrested apices and the reduction of apical inhibition produced by various Ca treatments indicated that the inhibition of apical growth was caused by Ca deficiency. When the rhizome apex was exposed to low humidity, a localized high-humidity treatment of the lateral buds did not release the buds from apical dominance in low-N rhizomes but strongly promoted bud growth at a higher N level. When growth of the buds was induced at low humidity by increasing the N supply, the increase in bud weight was preceded by an increase in the water content of the bud when expressed on a dry weight basis. These results agree with those of previous investigations and suggest that the interacting effects of N and humidity on the water status of the buds may play a significant role in the mechanism of apical dominance.

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.

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.

Differential Response of Ajuga (Ajuga reptans), Wintercreeper (Euonymus fortunei), and Dwarf Burning Bush (Euonymus alatus‘Compacta’) to Root- and Shoot-Applied Isoxaben

1999 ◽  
Vol 13 (4) ◽  
pp. 685-690 ◽  
Author(s):  
Sydha Salihu ◽  
Jeffrey F. Derr ◽  
Kriton K. Hatzios
Keyword(s):  
Shoot Growth ◽  
Sand Culture ◽  
Root Weight ◽  
Root Tips ◽  
Visible Injury ◽  
Culture Studies ◽  
Ajuga Reptans ◽  
Euonymus Fortunei ◽  
Shoot Weight ◽  
Root Treatment

Hydroponics and sand culture studies evaluated the effects of isoxaben rate (0.84, 1.69, and 3.39 kg/ha) and application type (root only, shoot only, and root plus shoot) on the growth of ajuga, wintercreeper, and dwarf burning bush. Similar responses were exhibited by the three species tested in both hydroponics and sand culture studies. Based on shoot weight reductions, dwarf burning bush was one to three times more sensitive than wintercreeper, which was the most tolerant of the three species, and ajuga was five to 20 times more sensitive than wintercreeper. Isoxaben applied to the root system at all three rates injured ajuga root tips and foliage and reduced root weight by approximately 40% and shoot weight by 20 to 30%. Isoxaben applications to ajuga foliage damaged the roots and leaves and caused over 30% reductions in shoot and root weights at the highest rate tested. Isoxaben applied to dwarf burning bush roots caused less than 20% shoot injury, reduced root weight by 8 to 18%, and reduced shoot weight by less than 10%. Application to dwarf burning bush foliage caused 20 to 30% injury, but only slight reductions in root and shoot weights were observed. No visible injury was observed in wintercreeper from any isoxaben application. However, root treatment reduced wintercreeper root weight by approximately 15%, and shoot treatment reduced shoot weight by 6 to 10% at the highest isoxaben rate tested. Application of isoxaben to both roots and foliage of wintercreeper resulted in similar reductions in shoot and root weights compared to root or shoot exposure alone. Shoot application to wintercreeper affected root growth, and root treatment reduced shoot growth.

Shoot growth, root growth and resource capture under limiting water and N supply for two cultivars of lettuce (Lactuca sativa L.)

2013 ◽  
Vol 371 (1-2) ◽  
pp. 281-297 ◽  
Author(s):  
P. J. Kerbiriou ◽  
T. J. Stomph ◽  
P. E. L. Van Der Putten ◽  
E. T. Lammerts Van Bueren ◽  
P. C. Struik
Keyword(s):  
Root Growth ◽  
Lactuca Sativa ◽  
Shoot Growth ◽  
Resource Capture ◽  
N Supply ◽  
Lactuca Sativa L

scholarly journals Does Ethylene Play a Role in the Release of Lateral Buds (Tillers) from Apical Dominance in Oats?

1982 ◽  
Vol 70 (3) ◽  
pp. 811-814 ◽  
Author(s):  
Marcia A. Harrison ◽  
Peter B. Kaufman
Keyword(s):  
Apical Dominance ◽  
Lateral Buds
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