scholarly journals Seasonal changes of violaxanthin cycle pigment de-epoxidation in wintergreen and evergreen plants.

2012 ◽  
Vol 59 (1) ◽  
Author(s):  
Olga Dymova ◽  
Tamara Golovko
Keyword(s):  
Seasonal Changes ◽  
Early Spring ◽  
Nonphotochemical Quenching ◽  
Thermal Dissipation ◽  
Direct Connection ◽  
Conifer Species ◽  
Picea Obovata ◽  
Ajuga Reptans ◽  
Xanthophylls Cycle ◽  
Evergreen Conifers

We studied carotenoids composition and the activities of the xanthophylls pigments in evergreen conifers (Abies sibirica, Juniperus communis, Picea obovata) and dwarf-shrub (Vaccinium vitis-idaea), and in wintergreen herbaceous plants (Ajuga reptans, Pyrola rotundifolia) growing near Syktyvkar (61°67(/) N 50°77(/) E). The carotenoid pool consisted mainly of following xanthophylls: lutein (70%), neoxanthin (7-10%) and a xanthophylls cycle component - violaxanthin (3-15%). Zeaxanthin and antheraxanthin were found in conifer samples collected in December-March while in other species - during all year. A direct connection between xanthophyll pigment de-epoxidation level and light energy thermal dissipation was shown only for boreal conifer species. It is proposed that zeaxanthin plays a central role in the dissipation of excess excitation energy (nonphotochemical quenching) in the antenna of photosystem II (PSII). We conclude that the increase in the extent of de-epoxidation is beneficial for the retention of PSII activity for conifers in early spring and for herbs in summer.

Seasonal changes in serum thyroid hormone levels in ruffed grouse maintained under natural conditions of temperature and photoperiod

1979 ◽  
Vol 57 (10) ◽  
pp. 2022-2027 ◽  
Author(s):  
A. Garbutt ◽  
J. F. Leatherland ◽  
A. L. A. Middleton
Keyword(s):  
Thyroid Hormone ◽  
Seasonal Changes ◽  
Gonadal Development ◽  
Early Spring ◽  
Light Period ◽  
Ruffed Grouse ◽  
Natural Conditions ◽  
Blood Samples ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels

Serum triiodothyronine (T3) and thyroxine (T4) concentrations were measured in a population of ruffed grouse, held outdoors under natural conditions of photoperiod and temperature. Blood samples were collected at monthly intervals, and at the solstices and equinoxes to test for variation through the light period. No changes in T4 or T3 levels were found during the light period but levels of T3 and T4 showed marked seasonal changes. Lowest T4 and T3 levels were found in birds during the winter months, with an increase in the concentration of both hormones in early spring concomitant with gonadal development in the adults. A lowering of serum T4 and T3 values was associated with the period of molt.

Needle browning and death in Pinus pumila in the alpine region of central Japan were not related to mechanical damage of cuticle and cuticle thickness

2012 ◽  
Vol 42 (1) ◽  
pp. 167-178 ◽  
Author(s):  
Aoi Nakamoto ◽  
Takefumi Ikeda ◽  
Emiko Maruta
Keyword(s):  
Natural Environment ◽  
Mechanical Damage ◽  
Early Spring ◽  
Alpine Region ◽  
Pinus Pumila ◽  
Central Japan ◽  
Alpine Regions ◽  
Cuticle Thickness ◽  
Cuticular Resistance ◽  
Evergreen Conifers

The browning and death of needles of evergreen conifers in alpine regions occur mainly in early spring at the point where the shoot protrudes from the snowpack. They are thought to be caused by excessive transpiration due to mechanical damage to the cuticle or to a thinner cuticle. However, there are a few studies that do not necessarily agree with this idea. We assessed needle browning and death in Pinus pumila (Pallas) Regel. in the alpine region of Japan in relation to mechanical damage to the cuticle, cuticular resistance, and cuticle thickness. Mechanical damage was not observed on needle cuticles of Pinus pumila browning in a natural environment. The color of needles with artificially abraded cuticles changed from green to brown in the abraded part. However, the brown color at the abraded part differed from the brown of a browning needle in its natural environment. There was no correlation between cuticular resistance and cuticle thickness. Needle browning and death in P. pumila were not related to mechanical damage of the cuticle or to cuticle thickness but might be due to changes in the quality and structure of the cuticle and other stresses.

Seasonal changes in concentrations of plasma hormones in the male ring dove (Streptopelia risoria)

1986 ◽  
Vol 108 (3) ◽  
pp. 385-391 ◽  
Author(s):  
R. W. Lea ◽  
P. J. Sharp ◽  
H. Klandorf ◽  
S. Harvey ◽  
I. C. Dunn ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Plasma Corticosterone ◽  
Early Spring ◽  
Energy Requirements ◽  
Breeding Cycle ◽  
Plasma Prolactin ◽  
Winter Solstice ◽  
Natural Lighting ◽  
Short Day ◽  
Ring Dove

ABSTRACT Seasonal changes in concentrations of plasma LH, prolactin, thyroxine (T4), GH and corticosterone were measured in captive male ring doves exposed to natural lighting at latitude 56 °N. Plasma LH levels decreased steeply in autumn when the daylength fell below about 12·5 h but increased in November as the birds became short-day refractory. In comparison with plasma LH concentrations in a group of short-day refractory birds exposed to 6 h light/day from the winter solstice, plasma LH levels in birds exposed to natural lighting increased further in spring after the natural daylength reached about 12·5 h. There were no seasonal changes in plasma prolactin concentrations and plasma T4 concentrations were at their highest during December, January and February, the coldest months of the year. The seasonal fall in plasma LH levels in September was associated with a transitory increase in plasma T4, a transitory decrease in plasma corticosterone and a sustained increase in plasma GH. It is suggested that in the ring dove, short-day refractoriness develops rapidly in November to allow the bird to breed when the opportunity arises, during the winter and early spring. The annual breeding cycle is synchronized by a short-day induced regression of the reproductive system in the autumn, the primary function of which may be to enable the birds to meet the energy requirements for the annual moult. The changes in plasma T4, corticosterone and especially of GH at this time of year are probably concerned with the control of moult or the associated changes in energy requirements. J. Endocr. (1986) 108, 385–391

The reproductive cycle of the viviparous seaperch, Cymatogaster aggregata Gibbons

1968 ◽  
Vol 46 (6) ◽  
pp. 1221-1234 ◽  
Author(s):  
John P. Wiebe
Keyword(s):  
Oocyte Maturation ◽  
Reproductive Cycle ◽  
Sertoli Cells ◽  
Reproductive Behavior ◽  
Seasonal Changes ◽  
Environmental Temperature ◽  
Interstitial Cells ◽  
Early Spring ◽  
Seminiferous Tubules ◽  
Male And Female

The natural reproductive cycle of male and female Cymatogaster aggregata is described with reference to gametogenesis, development of secondary sex structures, reproductive behavior, and gestation. Spermatocytogenesis starts in early spring and by June or July clusters of spermatozoa fill the seminiferous tubules. Concurrently the Sertoli cells and interstitial cells of Leydig increase in size and secondary sex structures develop on the male anal fin. When the sexes mingle in summer, the males perform very elaborate reproductive behavior. Fertilization occurs about mid-December—5 months after mating—and the ovary is then modified to maintain the young embryos until parturition in mid-summer. Oocyte formation is highest in July and August, just after parturition, while vitellogenesis and oocyte maturation occur mainiy from October to December. These seasonal changes are discussed in relation to changes in environmental temperature and photoperiod.

The effect of plane of nutrition and shearing on the pattern of the moult in Scottish Cashmere goats

2002 ◽  
Vol 74 (1) ◽  
pp. 177-188 ◽  
Author(s):  
M. Merchant ◽  
D.J. Riach
Keyword(s):  
Seasonal Changes ◽  
Early Spring ◽  
Energy Requirements ◽  
Plasma Prolactin ◽  
Length Data ◽  
Cashmere Goats ◽  
Ad Libitum ◽  
Maintenance Requirements ◽  
Circulating Levels ◽  
Staple Length

AbstractThe effect of plane of nutrition on the timing of the moult in cashmere goats was investigated. Three groups of mature does were individually offered food to supply 0·8 (L, no. = 14), 1·2 (M, no. = 14) or 20 (H, no. = 13) times their estimated maintenance energy requirements from mid December until mid May. Two other groups of goats which were shorn in mid January, were offered 1·2 times maintenance requirements from mid December until mid March when food levels were increased to either 1·6 M (SL, no. = 6) or ad libitum (SAL, no. = 6). In mid May mean live weights for treatments L, M, H, SL and SAL were 36·0, 41·5, 46·9, 33·0 and 43·1 kg (average s.e.d. = 2·27, P < 0·001).The pattern of moult was described by changes in a subjectively assessed moult score, the proportion of follicles with brushes and staple length. The loss of brushes, indicating the start of the moult, began from the primary follicles on days 143, 131, 76, 150 and 129 (average s.e.d. = 13·5, P < 0001), and from the secondary follicles on days 141, 128, 104, 144 and 125 (average s.e.d. = 14·1, P = 0·053) for treatments L, M, H, SL and SAL respectively. The loss of brushes from primary and secondary follicles was completed on average, by days 194 and 206 of the experiment respectively, and there were no differences between treatments. Moult score and staple length data confirmed the conclusion that lowering the plane of nutrition delayed the start of the moult. No additional effect of fleece removal in the shorn treatments was observed.Changes in circulating levels of plasma prolactin, thyroxine, tri-iodothyronine, insulin, insulin-like growth factor-1 and growth hormone were related to seasonal changes in daylength and plane of nutrition. Their rôle in the control of the moult is discussed.Manipulation of the nutrition of cashmere goats in early spring has the potential to delay and increase the synchrony of fibre moult and to improve the efficiency of cashmere harvesting.

Seasonal variations in forms of extractable sulfur in some New Zealand soils

Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 985 ◽  
Author(s):  
Z Tan ◽  
RG Mclaren ◽  
KC Cameron
Keyword(s):  
New Zealand ◽  
Seasonal Variations ◽  
Seasonal Changes ◽  
Early Spring ◽  
Continuous Increase ◽  
Organic C ◽  
The Third ◽  
Permanent Pasture ◽  
Low Levels ◽  
Inorganic Sulfate

Seasonal variations in different forms of extractable sulfur (S) were examined in three New Zealand soils under permanent pasture. The concentrations of total extractable S, extractable inorganic sulfate-S (SO2-4-S), and extractable organic HI-reducible sulfur (HI-S) and carbon-bonded sulfur (C-S) were determined in field moist samples using four different extractants. During the course of the year, extractable SO2-4-S levels varied substantially. Concentrations of SO42--S in the soils peaked in the early spring and, for two of the soils, remained at relatively low levels throughout the rest of the year. The third soil, however, following a decrease in concentration in late spring, showed a continuous increase in SO2-4-S during the summer and autumn period. Concentrations of extractable organic C-S in soils were generally highest in the winter and declined significantly during the spring. Extractable organic HI-S concentrations fluctuated throughout the year with no clear trends. The proportions of the three forms of extractable S in soils also varied seasonally. The proportions of extractable organic HI-S in soils were more constant compared with the other two forms of S and generally accounted for less than 20% of the total extractable S. The seasonal changes in the proportions of SO2-4-S appeared to be inversely related to the changes in extractable C-S. This suggests that under the field conditions, the extractable organic C-S fraction is readily mineralized to sulfate when conditions are favourable for mineralization to take place.

Seasonal changes in biomass and vertical distribution of mycorrhizal and fibrous-textured conifer fine roots in 23- and 180-year-old subalpine Abiesamabilis stands

1981 ◽  
Vol 11 (2) ◽  
pp. 224-230 ◽  
Author(s):  
Kristiina A. Vogt ◽  
Robert L. Edmonds ◽  
Charles C. Grier
Keyword(s):  
Root Growth ◽  
Vertical Distribution ◽  
Seasonal Changes ◽  
Forest Floor ◽  
Fine Roots ◽  
Early Spring ◽  
Silver Fir ◽  
Growing Up ◽  
Young Stand ◽  
Mycorrhizal Roots

Seasonal changes in biomass and vertical distribution of fibrous, mycorrhizal, and total conifer fine roots (≤ 2 mm) were examined in 23- and 180-year-old Pacific silver fir (Abiesamabilis (Dougl.) Forbes) ecosystems. In both stands, > 80% of fine roots was located in the upper 15 cm of the soil profile, in the forest floor (O1 and O2) and A horizon. During periods of active root growth in the young stand, significantly higher conifer root biomass occurred in the A horizon (370 to 690 g/m2) than the forest floor (200 to 350 g/m2). At all sampling times, a significantly higher biomass of conifer fine roots was located in the forest floor (550 to 1090 g/m2) than the A horizon (290 to 640 g/m2) in the old stand. In both stands, mycorrhizal roots comprised 10 to 15% of the total weight of conifer fine roots during peak root growth, 2 to 6% when roots were not growing, and 21 to 29% during the winter and early spring when roots were growing. Up to 69% of the biomass of fibrous and mycorrhizal roots was located in the forest floor in both stands.

Plasmatic protein values in captive adult Iberian red deer stags (Cervus elaphus hispanicus)

2010 ◽  
Vol 5 (5) ◽  
pp. 724-728
Author(s):  
Enrique Gaspar-López ◽  
Jose Estevez ◽  
Tomás Landete-Castillejos ◽  
Francisco Ceacero ◽  
Laureano Gallego ◽  
...  
Keyword(s):  
Cervus Elaphus ◽  
Seasonal Changes ◽  
Red Deer ◽  
Early Spring ◽  
Protein Electrophoresis ◽  
Blood Protein ◽  
Total Proteins ◽  
Mating Period ◽  
Cervus Elaphus Hispanicus ◽  
Iberian Red Deer

AbstractThe aim of this study was to assess the time trend of plasmatic proteins in red deer stags. Blood samples were taken monthly from 17 male red deer for 22 months. Total plasmatic determination and protein electrophoresis were performed. Plasmatic proteins showed minimum values during spring and summer and a maximum at the peak of the mating period. Total globulins, β and γ, followed a pattern similar to that observed for total proteins, whereas α1 and α2 globulins showed no seasonal variations. Albumin showed higher values in early spring and summer and lower values at the beginning of autumn, coinciding with the mating season. These seasonal changes in plasmatic proteins should be taken into account when assessing blood protein analysis results.

Influences of phenological differences on leaf-level carbon budget between the upper and lower crown of Lyonia ovalifolia

Botany ◽  
2013 ◽  
Vol 91 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Kenichi Yoshimura
Keyword(s):  
Seasonal Changes ◽  
Carbon Budget ◽  
Construction Cost ◽  
High Light Intensity ◽  
Early Spring ◽  
High Light ◽  
Physiological Characteristics ◽  
Single Crown ◽  
Leaf Level ◽  
Light Acquisition

To assess the significance of leaf phenology on leaf-level carbon budget, I measured seasonal changes in daily carbon budget of the upper and lower leaves within a single crown of Lyonia ovalifolia var. elliptica, a subcanopy tree species. Leaf-level carbon budget was evaluated as the product of area-based assimilation rates and leaf area minus leaf construction cost for a day. The area of the upper leaves gradually increased from spring to summer, whereas that of the lower leaves rapidly increased in early spring. Morphological, biochemical and physiological characteristics in lower leaves matured earlier than in upper leaves. Leaves in the lower crown produced a large amount of photosynthate (1.35 mg C·day−1) using the high light intensity of early spring. On the other hand the highest assimilation rate (5.23 mg C·day−1) was observed in late spring in the upper crown. Phenological differences in morphological and physiological characteristics among leaves in different positions within a crown can be interpreted as the acclimation to the seasonal changes in light acquisition for a leaf.

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