Anatomy and histochemistry of Abies balsamea cambial zone cells during the onset and breaking of dormancy

1984 ◽  
Vol 62 (12) ◽  
pp. 2570-2579 ◽  
Author(s):  
R. T. Riding ◽  
C. H. A. Little
Keyword(s):  
Succinic Dehydrogenase ◽  
Abies Balsamea ◽  
Growth Period ◽  
Radial Wall ◽  
Active Growth ◽  
Growing Period ◽  
Color Shift ◽  
Cambial Zone ◽  
Distinct Color ◽  
Ylacetic Acid

The anatomy and histochemistry of fusiform cambial zone cells were investigated (i) in shoots producing latewood tracheids at the time of collection in July and (ii) in dormant shoots. The latter were naturally or artificially chilled to obtain different stages along the rest–quiescence continuum, then placed for 4 weeks under environmental conditions favoring growth. The transition from active growth to rest was associated with increases in RNA, protein, and total insoluble carbohydrates and in peroxidase and succinic dehydrogenase activities. The rest–quiescence transition was correlated with additional increases in RNA and protein, an increase in lipid staining, radial wall thickness and plasmalemma infolding, and a decrease in vacuolar size. The DNA level did not appear to change; however, a distinct color shift occurred in nuclei stained for total protein. During the 4-week growth period, RNA, protein, total insoluble carbohydrates, and lipids decreased, most obviously in cambia that were fully quiescent at the start of the period. Xylem production and percentage of buds flushing during the growing period increased as the initial dormancy stage changed from rest to quiescence. Little, if any, xylem production occurred in debudded shoots unless indol-3-ylacetic acid (IAA) was supplied. Endogenous and exogenous lAA induced the same anatomical and histochemical responses.

Effect of cambial dormancy state on the transport of [1-14C]indol-3-ylacetic acid in Abies balsamea shoots

1981 ◽  
Vol 59 (3) ◽  
pp. 342-348 ◽  
Author(s):  
C. H. A. Little
Keyword(s):  
Abies Balsamea ◽  
Cambial Activity ◽  
Controlled Environment ◽  
Long Distance ◽  
Dormant Period ◽  
Cambial Zone ◽  
Time Required ◽  
Ylacetic Acid ◽  
Exogenous Iaa

Dormant attached or detached shoots of balsam fir were naturally or artificially chilled to induce different states along the rest–quiescence continuum. At the end of the chilling pretreatment, the shoots either were left intact or were debudded and treated with indol-3-ylacetic acid (IAA). The shoots were placed under controlled-environment conditions favorable for growth, and at intervals thereafter, a pulse of [1-14C]IAA was applied to the shoot apex. Measured at the end of the chilling pretreatment, [14C]IAA velocity and flux decreased with increasing duration of chilling (i.e., as rest graded into quiescence). The time required to commence cambial growth and to attain maximum rates of cambial activity and [14C]IAA transport also decreased as rest changed to quiescence. Transport in actively growing shoots exceeded that in quiescent shoots, but was similar to that in resting shoots. The [14C]IAA pulse moved basipetally as unchanged IAA, was blocked by a bark + cambium girdle, and was inhibited by abscisic acid and long-term application of exogenous IAA. The results indicate that: (1) the long-distance, cambium-located, IAA transport system demonstrated in dicotyledonous species also operates in conifers, (2) during the dormant period changes occur in [14C]IAA transport and in the cambial response to exogenous IAA, (3) the change in [14C]IAA transport is the result of change in the transporting capability of cells in the cambial zone, and (4) the change in [14C]IAA transport is not the cause of the differential response of quiescent and resting cambia to exogenous IAA.

Control of fusiform initial orientation in the vascular cambium of Abies balsamea stems by indol-3-ylacetic acid

1986 ◽  
Vol 64 (6) ◽  
pp. 1120-1128 ◽  
Author(s):  
B. Zagórska-Marek ◽  
C. H. A. Little
Keyword(s):  
Abies Balsamea ◽  
Anticlinal Wall ◽  
Intrusive Growth ◽  
Growing Period ◽  
Fusiform Initials ◽  
Tracheid Differentiation ◽  
Traumatic Resin Canals ◽  
Resin Canals ◽  
Ylacetic Acid ◽  
Fusiform Initial

Fusiform initial reorientation, deduced from changes in tracheid arrangement, was investigated in helical bridges left after Abies balsamea stems were girdled. The first responses included an increase in the number of S- and Z-oriented anticlinal divisions without any change in their ratio, a decrease in fusiform initial length, and the formation of traumatic resin canals. Subsequently, normal tracheid differentiation resumed, the frequency of anticlinal divisions further increased, and there was an increase in the number of oriented intrusive growth events. The orientations of the anticlinal wall and of the intrusive growth were predominantly in the direction that eventually would result in the fusiform initials being aligned parallel to the bridge angle. The application of exogenous indol-3-ylacetic acid to the upper edge of a helical bridge inhibited fusiform initial reorientation, mainly by decreasing the frequency of oriented intrusive growth events. However, immediately below the application point, exogenous indol-3-ylacetic acid also induced the fusiform initials to begin temporarily to realign so as to be perpendicular to the bridge angle. The transport of a pulse of [1-14C]indol-3-ylacetic acid applied to the shoot apex was inhibited 1 day after girdling in both helical and longitudinal bridges, particularly the former, whereas it was inhibited only in helical bridges at the end of a subsequent 11-week growing period. The degree of inhibition in the helical bridges was greater the day after girdling than at the end of the growing period, during which interval fusiform initial reorientation occurred at the bottom of the bridge width. The results support the conclusion that the orientation of fusiform initials is parallel to the direction of indol-3-ylacetic acid transport.

scholarly journals β-SNAP activity in the outer segment growth period is critical for preventing BNip1-dependent apoptosis in zebrafish photoreceptors

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuko Nishiwaki ◽  
Ichiro Masai
Keyword(s):  
Outer Segment ◽  
Protein Transport ◽  
Vesicular Transport ◽  
Growth Period ◽  
Retrograde Transport ◽  
Growing Period ◽  
Bh3 Domain ◽  
Retinal Photoreceptors ◽  
Spatio Temporal ◽  
Excessive Activation

Abstract BNip1, which functions as a t-SNARE component of the syntaxin18 complex, is localized on the ER membrane and regulates retrograde transport from Golgi to the ER. BNip1 also has a BH3 domain, which generally releases pro-apoptotic proteins from Bcl2-mediated inhibition. Previously we reported that retinal photoreceptors undergo BNip1-dependent apoptosis in zebrafish β-snap1 mutants. Here, we investigated physiological roles of BNip1-dependent photoreceptor apoptosis. First, we examined the spatio-temporal profile of photoreceptor apoptosis in β-snap1 mutants, and found that apoptosis occurs only during a small developmental window, 2–4 days-post-fertilization (dpf), in which an apical photoreceptive membrane structure, called the outer segment (OS), grows rapidly. Transient expression of β-SNAP1 during this OS growing period prevents photoreceptor apoptosis in β-snap1 mutants, enabling cone to survive until at least 21 dpf. These observations suggest that BNip1-mediated apoptosis is linked to excessive activation of vesicular transport associated with rapid growth of the OS. Consistently, knockdown of Ift88 and Kif3b, which inhibits protein transport to the OS, rescued photoreceptor apoptosis in β-snap1 mutants. Treatment with rapamycin, which inhibits protein synthesis via the mTOR pathway, also rescued photoreceptor apoptosis in β-snap1 mutants. These data suggest that BNip1 performs risk assessment to detect excessive vesicular transport in photoreceptors.

THE STUDY OF CLIMATE EFFECTS ON THE NUT YIELD OF COCONUT USING PARSIMONIOUS MODELS

1998 ◽  
Vol 34 (2) ◽  
pp. 189-206 ◽  
Author(s):  
T. S. G. PEIRIS ◽  
R. O. THATTIL
Keyword(s):  
Sunshine Duration ◽  
Growth Period ◽  
Climate Data ◽  
Active Growth ◽  
Dry Matter Partitioning ◽  
Air Temperatures ◽  
Nut Production ◽  
Parsimonious Models ◽  
June July ◽  
Active Growth Period

The coconut yield is harvested in six picks per year at two-monthly intervals. The yield variation between and within years is very complex and this variability has not yet been explained. The analysis of long-term nut yield and monthly climate data: rainfall (RF), pan evaporation (EV), sunshine duration (SS), wind velocity (WV), minimum and maximum air temperatures (TMIN and TMAX), and relative humidity in forenoons and afternoons (RHAM and RHPM), using multivariate methods enabled the use of the variables TMAX, RHPM and EV as significantly important determinants (parsimonious set of variables) to represent the effects of climate on coconut irrespective of picks. Parsimonious models developed using these three variables explain how the development of bunches during the active growth period responded to climate variables without physiological parameters. The models are desirable where interpretation is concerned. The yields of picks one to six were determined by the climate variability during February, June, July, September, December and February respectively. Based on the models the proper timing of the use of some agronomic practices to enhance the productivity was recommended. A common model was also fitted (R2 = 0.81; p < 0.002) to estimate the annual yield 18 months in advance using EV, RHPM and TMAX. The three variables influence the microclimate around the crown of the palm for utilizing solar radiation in dry matter partitioning and thereby nut production. The method used to screen climatic variables so as to develop parsimonious crop–weather models using multivariate and univariate techniques can be used for other tree crops.

Response of soya beans to planting date in south-eastern Queensland. II.* Vegetative and reproductive development

1974 ◽  
Vol 25 (5) ◽  
pp. 723 ◽  
Author(s):  
RJ Lawn ◽  
DE Byth
Keyword(s):  
Seed Yield ◽  
Vegetative Growth ◽  
Growth Period ◽  
Reproductive Development ◽  
Planting Date ◽  
Biological Efficiency ◽  
Vegetative Development ◽  
Planting Dates ◽  
Growing Period ◽  
Seed Yields

Vegetative and reproductive development of a range of soya bean cultivars was studied over a series of planting dates in both hill plots and row culture at Redland Bay, Qld. Responses in the extent of vegetative and reproductive development were related to changes in the phasic developmental patterns. The duration and extent of vegetative development for the various cultivar-planting date combinations were closely associated with the length of the period from planting to the cessation of flowering. Thus, vegetative growth was greatest for those planting dates which resulted in a delay in flowering and/or extended the flowering phase. Similarly, genetic lateness of maturity among cultivars was associated with more extensive vegetative development. Seed yield per unit area increased within each cultivar as the length of the growing period was extended until sufficient vegetative growth occurred to allow the formation of closed canopies under the particular agronomic conditions imposed. Further increases in the length of the period of vegetative growth failed to increase seed yield, and in some cases seed yields were actually reduced. Biological efficiency of seed production (BE) was negatively correlated with the length of the vegetative growth period. Differences in BE among cultivar-planting date combinations were large. It is suggested that maximization of seed yield will necessitate an optimum compromise between the degree of vegetative development and BE. Optimum plant arrangement will therefore vary, depending on the particular cultivar-planting date combination. ___________________ \*Part I, Aust. J. Agric. Res., 24: 67 (1973).

scholarly journals Long-term standardized forest phenology in Sweden: a climate change indicator

2019 ◽  
Author(s):  
Ola Langvall ◽  
Mikaell Ottosson Löfvenius
Keyword(s):  
Climate Change ◽  
Quantitative Methods ◽  
Food Resource ◽  
Growth Period ◽  
Phase Changes ◽  
Gradual Change ◽  
Active Growth ◽  
Statistical Precision ◽  
Active Growth Period

Abstract Because climate change alters patterns of vegetative growth, long-term phenological measurements and observations can provide important data for analyzing its impact. Phenological assessments are usually made as records of calendar dates when specific phase changes occur. Such assessments have benefits and are used in Citizen Science monitoring. However, these kinds of data often have low statistical precision when describing gradual changes. Frequent monitoring of the phenological traits of forest trees and berries as they undergo gradual change is needed to acquire good temporal resolution of transitions relative to other factors, such as susceptibility to frosts, insects, and fungi, and the use of berries as a food resource. Intensive weekly monitoring of the growth of apical and branch buds and the elongation of shoots and leaves on four tree species, and the abundance of flowers and berries of bilberry and lingonberry, has been performed in Sweden since 2006. Here, we present quantitative methods for interpolating such data, which detail the gradual changes between assessments in order to describe average rates of development and amount of interannual variation. Our analysis has shown the active growth period of trees to differ with latitude. We also observed a change in the timing of the maximum numbers of ripening berries and their successive decline. Data from tree phenology assessments can be used to recommend best forestry practice and to model tree growth, while berry data can be used to estimate when food resources for animals are most available.

Nitrogenase activity associated with Zostera marina from a North Carolina estuary

1982 ◽  
Vol 28 (4) ◽  
pp. 448-451 ◽  
Author(s):  
Garriet W. Smith ◽  
Steven S. Hayasaka
Keyword(s):  
North Carolina ◽  
Zostera Marina ◽  
Nitrogenase Activity ◽  
Growth Period ◽  
Winter Period ◽  
Late Winter ◽  
Active Growth ◽  
North Carolina Estuary ◽  
Active Growth Period

Nitrogenase activity (at in situ temperatures) associated with Zostera marina reflected the active growth periods of this plant in North Carolina coastal waters. During the plants most active growth period (late winter – spring) nitrogenase activity was primarily rhizospheric (8.47 μmol nitrogen fixed∙m−2∙day−1), while during its fall – early winter period it was primarily phyllospheric (8.03 μmol nitrogen fixed∙m−2∙day−1). No nitrogenase activity was detected during the warmer summer months when the plant is dormant. Phyllospheric nitrogenase activity (possibly the result of epiphytic heterocystic blue-green bacteria) was highest when plants were incubated aerobically in the presence of light.

The Metabolic Status of Traumatic Gum Ducts in Moringa Oleifera Lam.

IAWA Journal ◽  
1988 ◽  
Vol 9 (2) ◽  
pp. 187-195 ◽  
Author(s):  
S.V. Subrahmanyam ◽  
J.J. Shah
Keyword(s):  
Epithelial Cells ◽  
Moringa Oleifera ◽  
Succinic Dehydrogenase ◽  
Reaction Products ◽  
Radial Wall ◽  
Intense Staining ◽  
Phenolic Contents ◽  
Phloem Parenchyma ◽  
Tangential Wall ◽  
Moringa Oleifera Lam

Traumatic gum ducts develop lysigenously in the bark of Moringa oleifera Lam. as a result of injury. The phloem parenchyma cells at the locus of gum duct formation enlarge and are enriched with cytoplasm and nucleoplasm. These duct initials show higher succinic dehydrogenase (SDH) and acid phosphatase (ACPase) activities compared to the neighbouring cells. The duct initials undergo autolysis to form the duct lumen. The epithelial cells of a gum duct have various shapes and show intense staining for nucleic acids, proteins and insoluble polysaccharides as compared to the neighbouring cells. The epithelial cells are also rich in enzymes viz. SDH, ACPase and lipase. Epithelial cells show labyrinthine wall deposition. These deposits are more towards the duct lumen side than the radial wall side. The inner tangential wall of the epithelial cells facing the duct lumen appears swollen. The degenerating epithelial cells show diffuse reaction products of SDH and ACPase. Some epithelial cells accumulate phenolics and by autolysis of such cells their phenolic contents are released into the gum duct.

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