scholarly journals Time of Diapause Termination in the Pistachio Seed Wasp Eurytomα plotnikovi (Hymenoptera: Eurytomidae) ίη Northem Greece and Under Certain Photoperiods and Temperatures

2017 ◽  
Vol 13 ◽  
pp. 43 ◽  
Author(s):  
G. Haralambidis ◽  
M. E. Tzanakakis

Mummified pistachios containing fully grown diapause larvae of Eurytoma plotnikovi Nikol’skaya were collected from mid-November on from trees in coastal northern Greece and placed in a field cage. Every 5 weeks, fruits from the cage and from the trees were placed at 16L:8D h and 26°C. Pupation within I or 2 weeks showed that diapause was terminated between early April and early May. Two years later, strarting in early September, mummified fruits from the same trees were collected at bimonthly intervals and subjected fora few to several months to combinations of certain temperatures and photoperiods, followed by different conbinations of temperatures and photoperiods, then to 16L:8D h and 25°C. In larvae of early September, 6 months at 6°C was the most effective treatment for diapause termination. Diapause was also terminated or almost so after: (1) 4 months at 25°C and long photophase followed by 5 months at 14° or 6°C, (2) 4 months at 20°C and a 12 h photophase followed by 3 months at 14° or 6°C, (3) 4 months at WC and short photophase followed by 3 months at 6°C, and (4) 4 or 6 months at WC and short photophase. The results are in line with previous work, showing that, in larvae picked in early autumn, low temperatures and short days fora few to several months followed by high temperatures and a long day favor an early and synchronous termination of diapause. The time of diapause termination being in mid-spring, long days seem to be a reasonable signal for diapause termination, as shown by previous work. In larvae of early January, for a synchronous diapause termination four months at 20°C and a 12 h photophase followed by 3 months at WC and an 8 h photophase was the most effective treatment, without the need for a long-day final condition.

1959 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
FHW Morley ◽  
LT Evans

At various times throughout the winter, autumn-sown plants of five strains of subterranean clover were removed from the field to a series of day length and temperature treatments. The times to inflorescence initiation in all treatments were determined by dissection. As vernalization proceeded the requirement of all strains for long days was progressively reduced until, by midwinter, several strains had become virtually independent of day length. Similarly, with the progress of vernalization the inhibitory effects of high temperatures during short days became progressively less marked. Whereas exposure to long days at high temperatures greatly accelerated inflorescence initiation in all strains, long days at low field temperatures had little effect. Evidence is presented which suggests that the limiting effect of very low temperatures on initiation is due not only to retardation of the rate of inflorescence primordium formation (realization), but also to limitation of an inductive process other than vernalization and dark period inhibition. The flowering behaviour of the various strains is discussed in terms of their responses to the partial processes leading to inflorescence initiation, and the interrelationships of these processes are considered.


1975 ◽  
Vol 53 (14) ◽  
pp. 1400-1410 ◽  
Author(s):  
Judith F. Thomas ◽  
C. E. Anderson ◽  
C. David Raper Jr. ◽  
R. J. Downs

Nicotiana tabacum L. cv. Coker 319 has been found to be sensitive to changes both in temperature and photoperiod. Within a given time period fewer leaves are produced at low temperatures than at high temperatures. The classical day-neutral flowering response was not observed for this plant under six photoperiods of varying lengths. The results thus indicate that the plant may be more appropriately classified as being "preferentially ambiphotoperiodic," rather than strict "day-neutral." Preconditioning the seedlings with a long-day photoperiod produced plants that had higher total leaf numbers and flowered earlier than seedlings treated with a short-day photoperiod. The morphology of the vegetative and reproductive stem apex was similar to that reported for other species and cultivars of Nicotiana. Apical meristems were systematically ranked according to their progressive developmental stages encompassing vegetative, transition, and reproductive development.


Spurious kinks in estimated palaeogeotherms may result from small errors in the calibration of the geothermometers and geobarometers. New data indicate that the equilibrium solubility of alumina in enstatite is even less than shown by recent studies, and that the slopes (d T /d P ) of the isopleths of equal alumina content are steeper than hitherto believed. Consequently, pressures of equilibration estimated from current formulations of the orthopyroxene-garnet geobarometer will be too high at high temperatures (> 1200 °C) and too low at low temperatures.


2021 ◽  
Author(s):  
Haifeng Li ◽  
Xinyu ZHang ◽  
Yi Wu ◽  
Feng ZHang ◽  
CHunlin Li

Abstract Personality has been observed in a variety of animal taxa with important implications in ecology and evolution. Exploring the influence of environmental temperature during early life on personality could help to understand the ontogeny of this phenotypic trait in animals. In this study, we reared newborn mosquitofish Gambusia affinis at high (30°C) and low (25°C) water temperatures and measured their shyness and exploration upon sexual maturity. We tested the repeatability of each behavioral trait; the correlation between them; and the effects of rearing temperature, sex, and body length on the behaviors. When growing up at low temperatures, female fish exhibited repeatability in shyness and exploration, and males exhibited marginal repeatability in shyness. However, neither of the 2 behaviors were repeatable when the fish were reared at high temperatures. There was a negative correlation between shyness and exploration, indicating that the 2 behaviors comprise a behavioral syndrome in this species. Mosquitofish reared at high temperatures were more explorative than those reared at low temperatures, while there was no difference in shyness between the 2 treatments. Body length and sex had no significant effects on the average values of the 2 behaviors. The results indicate that environmental temperature during early life could shape the personality of mosquitofish and modify the average of the behavioral traits. These findings might provide insights to understand the ontogeny of animal personality and how changes in environmental temperature influence animal dispersal by shaping their personality.


2004 ◽  
Vol 811 ◽  
Author(s):  
Nobuhiro Kin ◽  
Koichiro Honda

ABSTRACTTo develop higher density FRAM requires reducing cell size. Therefore, the size effects resulting from device processing and the material's physical properties must be measured. Therefore, analyzing the electric characteristics of a single bit cell capacitor has become important. Two known characteristics of ferroelectric material are that the Vc increases at low temperatures, and the Pr falls at high temperatures. To further evaluate the impact of temperature on ferroelectrics, we constructed a new evaluation system based on a scanning probe microscope, that can measure the electric characteristics of a single bit cell capacitor. This system can be used in the temperature range from −120 degrees to 300 degrees C. We accomplished this by circulating liquid nitrogen around a SPM stage and by using an electrical heater. We measured the electrical properties of ferroelectric microcapacitors by using a sample with IrOx/PZT/Pt structure. Our measurements revealed that 2Pr really increases at low temperatures, and Pr decreases at high temperatures. That is, we have shown that Vc increases 30% at low temperatures and Pr decreases 10% also in an actual FRAM single bit cell capacitor.


2000 ◽  
Vol 646 ◽  
Author(s):  
Haruyuki Inui ◽  
Koji Ishikawa ◽  
Masaharu Yamaguchi

ABSTRACTEffects of ternary additions on the deformation behavior of single crystals of MoSi2 with the hard [001] and soft [0 15 1] orientations have been investigated in compression and compression creep. The alloying elements studied include V, Cr, Nb and Al that form a C40 disilicide with Si and W and Re that form a C11b disilicide with Si. The addition of Al is found to decrease the yield strength of MoSi2 at all temperatures while the additions of V, Cr and Nb are found to decrease the yield strength at low temperatures and to increase the yield strength at high temperatures. In contrast, the additions of W and Re are found to increase the yield strength at all temperatures. The creep strain rate for the [001] orientation is significantly lower than that for the [0 15 1] orientation. The creep strain rate for both orientations is significantly improved by alloying with ternary elements such as Re and Nb.


2021 ◽  
Vol 13 (1) ◽  
pp. 140-151
Author(s):  
Minrui Guo ◽  
Xinglin Zhou

The effects of the cross-anisotropy of different materials of the asphalt surface layer and the depth-temperature relationship on pavement responses and damage are investigated. A three-dimensional Finite-Element Model (FEM) of the pavement, which considers the depth-temperature relationship of the surface layer under moving tire load, is developed. Pavement damage models are established to evaluate the damage ratio for primary rutting and fatigue cracking. The results show that the compressive strain at the bottom of the surface layer increases as the temperature increases, and the cross-anisotropy (n-value) decreases, indicating that a decrease in the horizontal modulus of different materials of the surface layer increases the damage ratio for primary rutting at high temperatures. The tensile strain at the bottom of the surface layer declines as the n-value increases to 1. For the same change in the n-value, the rate of change of the damage ratio for fatigue cracking is greater at low temperatures than at high temperatures, demonstrating that the number of allowable load repetitions is more sensitive at low temperatures. In addition, the effect of cross-anisotropy and temperature on the vertical stress are larger on the top of the base than in the subbase and subgrade.


HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 719A-719
Author(s):  
Richard L. Harkess ◽  
Robert E. Lyons

A study was undertaken to determine the rate of floral initiation in Rudbeckia hirta. R. hirta plants were grown to maturity, 14-16 leaves, under short days (SD). Paired controls were established by placing half of the plants under long days (LD) with the remainder left under SD. Beginning at the start of LD (day 0), five plants were harvested daily from each photoperiod group for twenty days. Harvested meristems were fixed in 2% paraformaldehyde - 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.0) for 24 hrs, dehydrated in an ethanol series, embedded in paraffin and sectioned at 8 μm. Serial sections were stained with Methyl-green Pyronin, with adjacent sections treated with RNase for nucleic acid comparison. All events of floral initiation were identified, The results of limited inductive photoperiod indicate that 16-18 LD were required for flowering.


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