Dormancy and Root Regeneration of Northern Red Oak

1975 ◽  
Vol 5 (2) ◽  
pp. 176-185 ◽  
Author(s):  
R. E. Farmer Jr
Keyword(s):  
Abscisic Acid ◽  
Gibberellic Acid ◽  
Root Growth ◽  
Shoot Growth ◽  
Starch Content ◽  
Shoot Elongation ◽  
Northern Red Oak ◽  
Root Regeneration ◽  
Physiological Dormancy ◽  
Hydrolysis Of

In a greenhouse forcing study, root regeneration was correlated with shoot growth, which began with increasing rapidity as chilling requirements were met. Root growth was stimulated by factors originating in the stem of both dormant and growing plants, though root regeneration during physiological dormancy was limited. Auxins applied to decapitated plants stimulated root regeneration while inhibiting shoot growth; gibberellic acid, kinetin, ethylene, and abscisic acid had no direct effect upon root regeneration. The starch content of roots averaged 41% during dormancy, and major hydrolysis of starch was dependent upon initiation of shoot elongation.

Germination Characteristics of Bear Oak

1977 ◽  
Vol 1 (1) ◽  
pp. 19-20 ◽  
Author(s):  
Roosevelt Allen ◽  
Robert E. Farmer
Keyword(s):  
Gibberellic Acid ◽  
Root Growth ◽  
Leaf Area ◽  
Shoot Elongation ◽  
Germination Characteristics ◽  
Nursery Production ◽  
Quercus Ilicifolia ◽  
Spring Planting

Abstract Freshly collected bear oak (Quercus ilicifolia Wangenh.) seed from southwestern Virginia exhibited root growth under a range of temperatures but had epicotyl dormancy which was broken by stratification or gibberellic acid (GA3). Shoot elongation resulting from six weeks' chilling or GA3 was also influenced by temperature; a regime of 64°-75°F enhanced both percentage of seed with elongated shoots and leaf area per shoot relative to a 45°-61°F regime. Germination characteristics of seed lots from individual open-pollinated trees varied widely. Results suggest that fall-seeded beds will be most suitable in nursery production and that container stock for spring planting can be produced under greenhouse conditions with fall-stratified seed planted in early January.

scholarly journals Changes in Carbohydrate and Nitrogen Relationships during Episodic Growth of Ligustrum japonicum Thunb.

1997 ◽  
Vol 122 (5) ◽  
pp. 634-641 ◽  
Author(s):  
Jeff S. Kuehny ◽  
William B. Miller ◽  
Dennis R. Decoteau
Keyword(s):  
Root Growth ◽  
Plant Tissue ◽  
Shoot Growth ◽  
Soluble Sugars ◽  
Shoot Elongation ◽  
Total Soluble Sugars ◽  
Mature Leaves ◽  
Episodic Growth ◽  
Ligustrum Japonicum ◽  
Leaf Flush

Rooted cuttings of Ligustrum japonicum Thunb., an episodically growing species, were grown hydroponically in a controlled-environment growth chamber to determine allocation of glucose, mannitol, total soluble sugars, and total protein in mature leaves, flush leaves, stems, and roots. During the 65 days of episodic growth, 43% of the total soluble sugars was glucose and 33% mannitol. Glucose concentrations of mature leaves decreased during the first root growth episode, increased in almost all plant tissue during a shoot growth episode and decreased in all plant tissue at initiation of a second root growth episode. Mannitol concentrations in the roots and stems decreased during episodes of root growth and increased during a shoot growth episode when leaf flush mannitol concentrations increased. Radiolabeled C applied to leaves before the initiation of the first period of shoot elongation was translocated to the roots. After shoot elongation, just before a root growth episode, most labeled C was translocated to new shoots and roots. Autoradiographs indicated that subsequent episodes of shoot growth were supported by photosynthate from the previous shoot flush. Protein concentrations decreased in all plant tissues during shoot growth but increased in roots and mature leaves during root growth. Concentrations of 15N in leaf and stem tissue indicated retranslocated N supported each episode of shoot growth. Changes in endogenous C and N concentrations and allocation patterns in ligustrum were linked to the control of episodic shoot and root growth.

Duration of zinc uptake inhibition by chlorsulfuron in wheat

1992 ◽  
Vol 43 (5) ◽  
pp. 1169 ◽  
Author(s):  
LD Osborne ◽  
AD Robson
Keyword(s):  
Root Growth ◽  
Zinc Deficiency ◽  
Root Exudates ◽  
Shoot Growth ◽  
Zinc Uptake ◽  
Root Weight ◽  
Uptake Inhibition ◽  
Root And Shoot Growth ◽  
Shoot Weight ◽  
Hydrolysis Of

The duration of inhibition of zinc uptake by chlorsulfuron was examined in wheat plants in a glasshouse experiment. Chlorsulfuron decreased shoot weight, root weight and zinc uptake. Plants that were treated with chlorsulfuron and adequately supplied with zinc partially recovered from root and shoot growth inhibition by 6 weeks and zinc uptake was recovering by 8 weeks. Plants that were seriously zinc deficient did not recover. In this experiment, potential grain yield was only reduced by chlorsulfuron when zinc supplies were inadequate. It is suggested that the recovery of plants from zinc deficiency may be the result of two processes; hydrolysis of chlorsulfuron with time removing constraints to root growth and functioning, and the release of root exudates from zinc deficient plants effective at mobilizing zinc from soil. In the field, chlorsulfuron is only likely to induce zinc deficiency and reduce yield in wheat where supplies of this trace element are marginal for growth.

Pruning Northern Red Oak Nursery Seedlings: Effects on Root Regeneration and Early Growth

1975 ◽  
Vol 5 (3) ◽  
pp. 381-386 ◽  
Author(s):  
M. M. Larson
Keyword(s):  
Seedling Growth ◽  
Shoot Growth ◽  
Late Summer ◽  
Early Growth ◽  
Red Oak ◽  
Root Pruning ◽  
Root Weight ◽  
Northern Red Oak ◽  
Root Regeneration ◽  
Early Fall

Northern red oak seedlings were top-pruned in the seedbed each month from August until the next March. In late March, all trees were lifted, planted in the greenhouse, and harvested 30 days later. Any top-pruning treatment that directly or indirectly removed the leaves in late summer or early fall markedly reduced root regeneration and initial shoot growth after planting in March. Removal of all the visible buds at any date resulted in increased numbers of new shoots after planting, while pruning stems at the groundline reduced new shoot growth.In additional studies, shoots and roots of trees lifted in March were pruned to various levels before planting. Results indicated that root pruning influenced seedling growth much more than shoot pruning. The amount of new shoot growth was significantly correlated with root weight of seedlings when planted, whether differences in root weight were natural or obtained by pruning. The effects of shoot pruning and root pruning on seedling growth were largely independent of each other.

scholarly journals A Cytokinin Analog Thidiazuron Suppresses Shoot Growth in Potted Rose Plants via the Gibberellic Acid Pathway

2021 ◽  
Vol 12 ◽  
Author(s):  
Fisun G. Çelikel ◽  
Qingchun Zhang ◽  
Yanlong Zhang ◽  
Michael S. Reid ◽  
Cai-Zhong Jiang
Keyword(s):  
Gibberellic Acid ◽  
Shoot Growth ◽  
Shoot Elongation ◽  
Ethylene Biosynthesis ◽  
Silver Thiosulfate ◽  
Cell Architecture ◽  
Leaf Yellowing ◽  
Genes Encoding ◽  
Acid Pathway ◽  
Ga Biosynthesis

Application of thidiazuron (N-phenyl-N′-1,2,3-thiadiazol-5-ylurea, TDZ), a cytokinin analog, to inhibit the leaf yellowing that occurs after pinching potted rose plants, resulted in compact plants with shorter shoots and thicker internodes. Two weeks after treatment with 100 μM of TDZ, new shoots were half as long as those in control plants, and stem diameters were about 40% greater. This effect of TDZ is associated with changes in cell architecture. Although TDZ treatment stimulated ethylene production by the plants, inhibitors of ethylene biosynthesis (2-aminoethoxyvinyl glycine) or action (silver thiosulfate) did not affect the response of plants to TDZ. We found that TDZ treatment significantly suppressed the expression of bioactive gibberellic acid (GA) biosynthesis genes encoding GA3 and GA20 oxidases and slightly increased the expression of GA catabolism genes encoding GA2 oxidase. Application of GA3 and TDZ together resulted in normal elongation growth, although stem diameters were still somewhat thicker. Our results suggest that TDZ regulates shoot elongation and stem enlargement in potted rose plants through the modulation of bioactive GA biosynthesis.

Root growth and root growth capacity of white spruce (Piceaglauca (Moench) Voss) seedlings

1985 ◽  
Vol 15 (4) ◽  
pp. 625-630 ◽  
Author(s):  
Anne M. Johnson-Flanagan ◽  
John N. Owens
Keyword(s):  
Root Growth ◽  
Root Elongation ◽  
Shoot Growth ◽  
Lateral Roots ◽  
White Spruce ◽  
Shoot Elongation ◽  
Growth Capacity ◽  
Root Growth Capacity ◽  
Root And Shoot Growth

Root growth in the root systems of Styroplug-grown white spruce (Piceaglauca (Moench) Voss) seedlings increases in the spring before shoot elongation and again in the fall after bud development is complete. This is followed by root dormancy and quiescence, which are distinguished on the basis of ability to elongate under root growth capacity (RGC) conditions. The number of white long lateral roots produced during RGC tests correlated significantly with the number of white long lateral roots under lathhouse conditions. Increased mitotic activity is required for root elongation. However, mitotic frequencies could not be used to assess RGC because of the confounding effects of independent growth cycles in individual roots. Cell expansion and transformation of insoluble carbohydrates are important controls of root elongation. The relationship between root and shoot growth under RGC conditions may not support the role of shoot elongation in decreasing root elongation. Conversely, this may indicate that RGC tests alter the endogenous controls of root and shoot growth.

Nitrate controls testa rupture and water content during release of physiological dormancy in seeds of Sisymbrium officinale (L.) Scop.

2015 ◽  
Vol 25 (2) ◽  
pp. 138-146 ◽  
Author(s):  
Peter E. Toorop
Keyword(s):  
Abscisic Acid ◽  
Gibberellic Acid ◽  
Water Content ◽  
Sensu Stricto ◽  
Second Phase ◽  
Dormancy Release ◽  
Synthesis Inhibitor ◽  
Seed Analysis ◽  
Physiological Dormancy ◽  
Radicle Protrusion

AbstractSeeds of Sisymbrium officinale display physiological dormancy and require nitrate to germinate. Rupture of the testa precedes radicle protrusion through the endosperm (germination sensu stricto). While both endosperm rupture and testa rupture (TR) required nitrate, endosperm rupture was fully inhibited by abscisic acid (ABA) but TR was not inhibited. The gibberellic acid (GA)-synthesis inhibitor paclobutrazol prevented TR, which was reverted by exogenous GA4 but not by nitrate. The orientation of TR was transverse, which prompted the question whether seeds elongate prior to radicle protrusion, concurrent with an increase in water content. Between 9 h and 1 d no increase in length or water content was observed. During incubation in ABA the length of imbibed seeds without TR did not increase between 1 and 5 d, whereas nitrate added to ABA induced TR and a 94% increase in length. At the same time the water content of seeds without TR increased by 18%, while the water content of seeds with TR increased by 38%. Length and water content were correlated in a single-seed analysis for seeds with TR, but not for seeds without TR. Increased length was also observed in Arabidopsis seeds with nitrate-induced TR. These results indicate that prior to endosperm rupture dormancy release by nitrate is accompanied by TR, seed elongation and an increase in water content. A new multiphasic model is proposed for the imbibition curve, where the second phase of the classical triphasic curve is split into three sub-phases, of which phases IIB and IIC are associated with TR.

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