Hormonal control of the respiratory climacteric in Sauromatum guttatum (Araceae)

1971 ◽  
Vol 49 (8) ◽  
pp. 1373-1377 ◽  
Author(s):  
Richard G. Buggeln ◽  
Bastiaan J. D. Meeuse
Keyword(s):  
Staminate Flower ◽  
Hormonal Control ◽  
Terminal Portion ◽  
Flower Buds ◽  
Direct Addition ◽  
Controlled Conditions ◽  
Arum Maculatum ◽  
Time Required ◽  
Sauromatum Guttatum

A respiratory climacteric (RC) occurs in the appendix (terminal portion of the spadix) of the inflorescence of Sauromatum guttatum Schott during blooming. We have devised purification techniques and a bioassay for calorigen, the compound (synthesized in the staminate flower buds) which triggers the RC in the Sauromatum appendix.Inflorescences were induced to bloom under controlled conditions to determine (1) the time required for calorigen to be released from the staminate flowers and to accumulate in the appendix, and (2) the time required for calorigen to trigger the RC in the appendix. The latter results were confirmed by the direct addition of calorigen to appendix sections in a bioassay.A calorigen-like substance was extracted from the staminate flowers of Arum maculatum, A. italicum, A. dioscoridis, and Dracunculus vulgaris.

Development rate, fecundity and lifespan of apterae of the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), under controlled conditions

1987 ◽  
Vol 77 (4) ◽  
pp. 629-635 ◽  
Author(s):  
Y. K. Aalbersberg ◽  
F. Du Toit ◽  
M. C. Van Der Westhuizen ◽  
P. H. Hewitt
Keyword(s):  
Russian Wheat Aphid ◽  
Diuraphis Noxia ◽  
Development Rate ◽  
Rate Of Development ◽  
Complete Development ◽  
Controlled Conditions ◽  
Time Required

AbstractThe rate of development, fecundity and lifespan of apterae of Diuraphis noxia (Mordvilko) were determined at five sets of temperature and daylength conditions. The time required to complete pre-imaginal growth at mean daily temperatures of 10, 13, 14, 17·25 and 20°C was 19·70, 12·09, 11·25, 9·88 and 8·17 days, respectively. The threshold for development was estimated to be 0·54°C and the number of day-degrees C required to complete development was 158·73.

scholarly journals Corticosterone and timing of migratory departure in a songbird

2017 ◽  
Vol 284 (1846) ◽  
pp. 20162300 ◽  
Author(s):  
Cas Eikenaar ◽  
Florian Müller ◽  
Clara Leutgeb ◽  
Sven Hessler ◽  
Konstantin Lebus ◽  
...  
Keyword(s):  
Physiological Mechanism ◽  
Hormonal Control ◽  
Major Step ◽  
Extrinsic Factors ◽  
Stopover Site ◽  
High Baseline ◽  
Intrinsic Factors ◽  
Baseline Corticosterone ◽  
Departure Decisions ◽  
Time Required

Bird migration entails replenishing fuel stores at stopover sites. There, individuals make daily decisions whether to resume migration, and must also decide their time of departure. Variation in departure timing affects the total time required to complete a migratory journey, which in turn affects fitness through arrival time at the breeding and wintering grounds. It is well established that stopover departure decisions are based on cues from innate rhythms, intrinsic factors and extrinsic factors. Yet, virtually nothing is known about the physiological mechanism(s) linking these cues to departure decisions. Here, we show for a nocturnal migratory songbird, the northern wheatear ( Oenanthe oenanthe ), that baseline corticosterone levels of birds at stopover increased both over the migratory season and with wind assistance towards the migratory destination. Corticosterone in turn predicted departure probability; individuals with high baseline corticosterone levels were more likely to resume migration on a given night. Corticosterone further predicted the departure time within the night, with high baseline levels being associated with early departures. These novel findings indicate that corticosterone may be mediating between departure cues and the timing of departure from a stopover site, which is a major step towards understanding the hormonal control of animal migration.

DISTRIBUTION, ABUNDANCE, AND SURVIVAL OF THE BALSAM WOOLLY APHID, ADELGES PICEAE (HOMOPTERA: PHYLLOXERIDAE), ON BRANCHES OF BALSAM FIR, ABIES BALSAMEA

1976 ◽  
Vol 108 (10) ◽  
pp. 1097-1111 ◽  
Author(s):  
D. G. Bryant
Keyword(s):  
Staminate Flower ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Ecological Studies ◽  
Mortality Factors ◽  
Flower Buds ◽  
Sample Unit ◽  
Woolly Aphid ◽  
Adelges Piceae

AbstractOver 95% of feeding balsam woolly aphids occur in crevices on balsam fir branches and the highest density occurs within the 3-year tip of branches. The crevices occur under the bud scales at nodes, the base of each season’s growth, and among staminate flower buds or among and within flower bracts. The abundance and survival of aphids as well as mortality factors vary with the location of the nodes in a branch, the type of branch, and aphid generation. The significant differences show that there are 9 to 13 strata within the 3-year tip of a branch. For ecological studies and measuring population levels, the cluster of aphids within a defined crevice, for example under the bud scale at the base of a cluster of shoots, can be selected as a sample unit.

Microstructural Mechanism of Electromigration Failure In Narrow Interconnects

1993 ◽  
Vol 309 ◽  
Author(s):  
Choongun Kim ◽  
S. I. Selister ◽  
J. W. Morris
Keyword(s):  
Stable Distribution ◽  
Time To Failure ◽  
Controlled Conditions ◽  
Different Temperatures ◽  
Time Required ◽  
Microstructural Studies ◽  
Microstructural Mechanism

AbstractMicrostructural studies of electromigration failure were performed on A1-2Cu-1Si interconnects with 1.3 μm width. The lines were tested to failure under controlled conditions after pre-aging for various times at three different temperatures. Examination of the microstructure of the failure sites suggests that the lines fail at the bamboo grains that terminate the longest polygranular segments in the line. Transgranular slit voids form after Cu has been swept from the grain that fails. Hence, pre-aging lines to create a more stable distribution of Cu lengthens the time required to sweep Cu and significantly increases the time to failure. The optimal microstructure has a maximum intragranular density of stable θ precipitates. In this case transgranular slit failure is suppressed, and the bamboo grain fails by diffuse thinning to rupture.

scholarly journals Dormant Pruning and Fall Ethephon Application Influence Peach Pistil Hardiness

1995 ◽  
Vol 120 (5) ◽  
pp. 823-829 ◽  
Author(s):  
Edward F. Durner
Keyword(s):  
Significant Interaction ◽  
Prunus Persica ◽  
Heat Accumulation ◽  
Flower Buds ◽  
Flower Bud ◽  
Controlled Conditions ◽  
Main Effect ◽  
Ethephon Treatment

Flower bud hardiness of ethephon-treated (100 mg·liter-1 in October), dormant pruned (in December) `Redhaven' peach (Prunus persica L. Batsch.) trees was studied from December through March using exotherm analysis. In early December, buds not treated with ethephon were 0.5C hardier than ethephon-treated buds. From mid-December through March, ethephon-treated buds were 0.5 to 2.1C hardier than nontreated buds. When a main effect of pruning was detected, buds from pruned trees were 0.8 to 2.8C less hardy than buds from nonpruned trees. On several dates, a significant interaction on flower bud hardiness between ethephon treatment and pruning was detected. For trees not treated with ethephon, buds from pruned trees were 1.8 to 2.2C less hardy than those from nonpruned trees. Pruning did not affect hardiness of buds from ethephon-treated trees. Ethephon delayed bloom to the 75% fully open stage by 9 days. Pruning accelerated bloom to the 75% fully open stage by 3 days compared to nonpruned trees. Flower bud dehardening under controlled conditions was also studied. As field chilling accumulated, flower buds dehardened more rapidly and to a greater extent when exposed to heat. Pruning accelerated and intensified dehardening. Ethephon reduced the pruning effect. The percentage of buds supercooling from any ethephon or pruning treatment did not change as chilling accumulated. In trees not treated with ethepbon, fewer buds supercooled as heat accumulated, and pruning intensified this effect. In pruned, ethephon-treated trees, fewer buds supercooled after exposure to heat. The number of buds supercooling in nonpruned trees did not change with heat accumulation. Flower bud rehardening after controlled dehardening was also evaluated. After dehardening in early February, there was no difference in the bud hardiness of pruned or nonpruned trees. Buds from ethepbon-treated trees were hardier than those from nontreated trees. With reacclimation, buds from pruned trees were not as hardy as those from nonpruned trees. The percentage of buds supercooling from ethephon-treated trees did not change with deacclimation or reacclimation treatments. After deacclimation in late February, buds from pruned trees were 2.2C less hardy than those from nonpruned trees. After reacclimation, buds from pruned, ethephon-treated trees rehardened 2.6C while buds from all other treatments remained at deacclimated hardiness levels or continued to deharden. Ethephon-treated pistils were shorter than nontreated pistils. Pistils from pruned trees were longer than those from nonpruned trees. Deacclimated pistils were longer than nondeacclimated pistils. Differences in hardiness among ethephon and pruning treatments were observed, but there was no relationship between pistil moisture and hardiness.

A Possible Role for Abscisic Acid in Controlling Dormancy in Jojoba Flower Buds

1985 ◽  
Vol 12 (5) ◽  
pp. 463 ◽  
Author(s):  
A Benzioni ◽  
RL Dunstone
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Low Temperatures ◽  
Water Status ◽  
Effect Of Temperature ◽  
Flower Buds ◽  
Controlled Conditions ◽  
Effects Of Temperature ◽  
Delayed Flowering ◽  
Endogenous Aba

Jojoba flower buds break dormancy in response to low temperatures in the presence of adequate water. The possibility that abscisic acid (ABA) is involved in the regulation of dormancy was examined by following endogenous ABA levels in flower buds and leaves and by applying synthetic (�)-ABA. Under controlled conditions endogenous levels of ABA were high in dormant flower buds and decreased under conditions of low temperatue that led to flowering. Similar results were obtained in the field. Levels in the leaves were low and changes in response to environmental treatments were small. Daily spraying of the plants with water containing 0.01% Tween enhanced flowering while water stress inhibited it. The application of (�)-ABA delayed flowering and reduced the percentage of flowers open at the end of the experiment. An experiment aimed at distinguishing between the effects of temperature and of water status was inconclusive and part of the effect of temperature on ABA may be related to the effect of temperature on the water status of plant.

scholarly journals Citrus Shoot Age and Flowering Potential

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1145B-1145
Author(s):  
L. Gene Albrigo
Keyword(s):  
Late Summer ◽  
Flower Buds ◽  
Flower Bud ◽  
Bud Induction ◽  
Citrus Leaves ◽  
Time Required ◽  
Severe Leaf

Three hurricanes in Florida starting in late Summer 2004 caused severe leaf loss, which stimulated many fall shoots. Flush occurred after each hurricane and by December, shoots were 6- to 12-weeks-old when cool temperatures capable of causing flower bud induction started. To evaluate the potential for these flushes to mature buds that could be induced to flower, flushes that were stimulated on potted trees in a greenhouse were allowed to mature 4, 6, 8, or 10 weeks before moving trees to flower-inducing conditions for 6 weeks (15 °C day/10 °C night). Plants were then returned to the greenhouse, which was kept at 20 °C or higher (ambient), until buds sprouted. Only 1% of sprouting buds on shoots that matured for 4 weeks had flowers. In shoots that matured for 6 weeks, 18% of sprouting buds had flowers. After 8 weeks of growth, 57% of the buds that sprouted were flower buds, while after allowing 10 weeks for shoots to mature, induction resulted in 76% of the sprouting buds producing flowers. Consequently, 8 weeks of development were necessary for citrus shoots to develop mostly mature buds that responded to flower inductive conditions. This is about the same amount of time required for new citrus leaves to fully mature.

scholarly journals Pyruvate transport by thermogenic-tissue mitochondria

1987 ◽  
Vol 247 (2) ◽  
pp. 441-447 ◽  
Author(s):  
M O Proudlove ◽  
R B Beechey ◽  
A L Moore
Keyword(s):  
Alternative Oxidase ◽  
Competitive Inhibition ◽  
Feedback Inhibition ◽  
Total Activity ◽  
Mitochondrial Inner Membrane ◽  
Pyruvate Oxidation ◽  
Cytochrome Pathway ◽  
Arum Maculatum ◽  
Long Chain ◽  
Sauromatum Guttatum

1. Mitochondria isolated from the thermogenic spadices of Arum maculatum and Sauromatum guttatum plants oxidized external NADH, succinate, citrate, malate, 2-oxoglutarate and pyruvate without the need to add exogenous cofactors. 2. Oxidation of substrates was virtually all via the alternative oxidase, the cytochrome pathway constituting only 10-20% of the total activity, depending on the stage of spadix development. 3. During later stages of spadix development, pyruvate oxidation was enhanced by the addition of aspartate. This was caused by acetyl-CoA condensing with oxaloacetate, produced from pyruvate/aspartate transamination, and so decreasing feedback inhibition of pyruvate dehydrogenase. 4. Pyruvate oxidation was inhibited by the long-chain acid maleimides AM5-11, but not by those with shorter polymethylene side groups, AM1-4. 5. The alpha-cyanocinnamate derivatives UK5099 [alpha-cyano-beta-(1-phenylindol-3-yl)acrylate] and CHCA [alpha-cyano-4-hydroxycinnamate] inhibited pyruvate-dependent O2 consumption and the carrier-mediated uptake of pyruvate across the mitochondrial inner membrane. Characteristics of non-competitive inhibition were observed for CHCA, whereas for UK5099 the results were more complex, suggesting a very low rate of dissociation of the inhibitor-carrier complex. 6. A comparison of the values of Vmax. and Km for oxidation and transport suggested that it was the latter which controls the overall rate of pyruvate oxidation by mitochondria from both tissues.

scholarly journals Blooming Date Predictions Based on Japanese Apricot ‘Nanko’ Flower Bud Responses to Temperatures during Dormancy

HortScience ◽  
2017 ◽  
Vol 52 (3) ◽  
pp. 366-370 ◽  
Author(s):  
Yuto Kitamura ◽  
Hisayo Yamane ◽  
Akira Yukimori ◽  
Hiroyoshi Shimo ◽  
Koji Numaguchi ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Linear Functions ◽  
Flower Buds ◽  
Flower Bud ◽  
Japanese Apricot ◽  
Practical Applications ◽  
Heat Requirements ◽  
Time Required ◽  
The Relationship ◽  
Different Climates

Flower bud development and the timing of blooming are mainly affected by genotype-dependent chilling requirements (CRs) during endodormancy and subsequent heat requirements (HRs) during ecodormancy. However, little information is available regarding the responses of flower buds to temperatures during endodormancy and ecodormancy in japanese apricot. We exposed japanese apricot ‘Nanko’ trees to various temperatures to estimate the CRs and HRs using development index (DVI) models specific for the endodormant (DVIendo) and ecodormant (DVIeco) stages. These models were based on the experimentally determined development rate (DVR). The DVRendo value was calculated as the reciprocal of the chilling time required to break endodormancy. The relationship between the DVRendo value and temperature was estimated using a three-dimensional curve. Our results indicated that 5–6 °C was the most effective temperature for breaking endodormancy in ‘Nanko’ flower buds. Additionally, exposure to −3 °C negatively affected endodormancy release, whereas 15 °C had no effect. We also determined that the DVReco values for temperatures between 5 and 20 °C were the reciprocal values of the time required for blooming after endodormancy release. The values outside this range were estimated using linear functions. The DVI was defined as the sum of the DVR values ranging from 0 to 1. Models for predicting the blooming date were constructed using the functions of sequentially combined DVIendo and DVIeco models. The accuracy of each model was assessed by comparing the predicted and actual blooming dates. The prediction of the model in which DVIeco = 1 corresponded to a 40% blooming level and DVIeco = 0 was set to DVIendo = 0.5 had the lowest root mean square error (RMSE) value (i.e., 3.11) for trees in commercial orchards exposed to different climates. Our results suggest that the developed model may have practical applications.

Sign in / Sign up

Export Citation Format

Share Document