Flower initiation in relation to maturity in crop plants. I. Flower initiation in relation to maturity in some Australian oats (Avena spp.)

1961 ◽  
Vol 12 (3) ◽  
pp. 371 ◽  
Author(s):  
Y Aitken
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Subterranean Clover ◽  
Late Summer ◽  
Crop Plants ◽  
Leaf Number ◽  
Flower Initiation ◽  
Early Group ◽  
Wide Range ◽  
Cold Requirement

The description of oat varieties as early, mid, and late depends mainly on differences in their time of flower initiation. Flower initiation has been studied in varieties grown in southern Australia and ranging in maturity from first early to late. The time to flower initiation was found to depend greatly on the variety�s response to photoperiod and temperature. In all groups but the first early one, initiation was hastened by lengthening photoperiod and reducing temperature. The later the variety, the greater was the effect. Early varieties are those in which initiation occurs at a low leaf number over a wide range of photoperiods and temperatures. Late varieties result from initiation at a high leaf number, the delay compared with early varieties being due to sensitivity to high temperatures and to short photoperiods. These are the conditions prevailing after late summer and autumn sowings. Late varieties mature early in the field when grown either at low temperatures (below 50�F), or at slightly higher temperatures (below 60�F) and intermediate photoperiod. This is similar to the reaction of variety Clare in the second early group of' subterranean clover. Very late varieties of oats, similar to winter wheats which have a pronounced cold requirement for initiation, are not yet present in Australia.

Flower initiation in Trifolium subterraneum L. II. Limitations by vernalization, low temperatures, and photoperiod, in the field at Canberra

1959 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
FHW Morley ◽  
LT Evans
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Day Length ◽  
Flower Initiation ◽  
Inhibitory Effects ◽  
Low Field ◽  
The Times ◽  
Short Days

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.

scholarly journals Sensitivity of barley varieties to weather in Finland

2011 ◽  
Vol 150 (2) ◽  
pp. 145-160 ◽  
Author(s):  
K. HAKALA ◽  
L. JAUHIAINEN ◽  
S. J. HIMANEN ◽  
R. RÖTTER ◽  
T. SALO ◽  
...  
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Heat Waves ◽  
Accumulation Rate ◽  
Extreme Weather Events ◽  
Seasonal Temperature ◽  
Accumulation Rates ◽  
Temperature Sum ◽  
Wide Range ◽  
General Response

SUMMARYGlobal climate change is predicted to shift seasonal temperature and precipitation patterns. An increasing frequency of extreme weather events such as heat waves and prolonged droughts is predicted, but there are high levels of uncertainty about the nature of local changes. Crop adaptation will be important in reducing potential damage to agriculture. Crop diversity may enhance resilience to climate variability and changes that are difficult to predict. Therefore, there has to be sufficient diversity within the set of available cultivars in response to weather parameters critical for yield formation. To determine the scale of such ‘weather response diversity’ within barley (Hordeum vulgare L.), an important crop in northern conditions, the yield responses of a wide range of modern and historical varieties were analysed according to a well-defined set of critical agro-meteorological variables. The Finnish long-term dataset of MTT Official Variety Trials was used together with historical weather records of the Finnish Meteorological Institute. The foci of the analysis were firstly to describe the general response of barley to different weather conditions and secondly to reveal the diversity among varieties in the sensitivity to each weather variable. It was established that barley yields were frequently reduced by drought or excessive rain early in the season, by high temperatures at around heading, and by accelerated temperature sum accumulation rates during periods 2 weeks before heading and between heading and yellow ripeness. Low temperatures early in the season increased yields, but frost during the first 4 weeks after sowing had no effect. After canopy establishment, higher precipitation on average resulted in higher yields. In a cultivar-specific analysis, it was found that there were differences in responses to all but three of the studied climatic variables: waterlogging and drought early in the season and temperature sum accumulation rate before heading. The results suggest that low temperatures early in the season, delayed sowing, rain 3–7 weeks after sowing, a temperature change 3–4 weeks after sowing, a high temperature sum accumulation rate from heading to yellow ripeness and high temperatures (⩾25°C) at around heading could mostly be addressed by exploiting the traits found in the range of varieties included in the present study. However, new technology and novel genetic material are needed to enable crops to withstand periods of excessive rain or drought early in the season and to enhance performance under increased temperature sum accumulation rates prior to heading.

The flowering responses of crop and pasture species in Australia I. Factors affecting development in the field of Lolium species (L. rigidum Gaud., L. perenne L., L. multiflorum Lam.)

1966 ◽  
Vol 17 (6) ◽  
pp. 821 ◽  
Author(s):  
Y Aitken
Keyword(s):  
Early Summer ◽  
Winter Temperature ◽  
Flower Initiation ◽  
Early Group ◽  
Lolium Rigidum ◽  
Factors Affecting ◽  
Cold Requirement

Cultivars of three species of ryegrass (Lolium rigidum Gaud., L. perenne L., and L. multiflorum Lam.) were grown in the open and in the glasshouse at Melbourne (lat. 38° S.), with additional lighting and vernalization when required. They were sown at different times through the year and were compared for times of flower initiation and heading and for leaf numbers to heading. They included two early cultivars (Wimmera, Kangaroo Valley), four mid-season ones (Victorian, Grasslands Ruanui, Tasmanian No. 1, Grasslands Paroa), and one late one (S.23) from England. For all cultivars studied, some cold was required for flower initiation, while long days hastened it somewhat; development between initiation and heading was hastened by both warmth and long days. The early group with a small cold requirement initiated in winter and spring and headed in spring and summer. The mid-season group with a larger cold requirement initiated only in spring, and headed in mid spring to early summer. The late cultivar headed scantily or not at all, the winter temperature being too high for initiation.

Flower initiation in Trifolium subterraneum L. 1. Analysis of the partial processes involved

1959 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
LT Evans
Keyword(s):  
High Temperatures ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Controlled Environment ◽  
Flower Initiation ◽  
Inhibitory Process ◽  
Inhibitory Effects ◽  
Other Hand ◽  
Short Days

The influence of various temperature and photoperiod regimes on flower initiation and flowering in eight strains of T. subterraneum has been examined, using the controlled environment facilities of the Earhart Laboratory. Flower initiation in subterranean clover appears to be under the control of three interacting partial processes, two of which are synergistic and promotive while the third is inhibitory. The promotive processes are possibly both light-independent, one being favoured by high temperatures and the other (the vernalization process) by low temperatures. The inhibitory process, on the other hand, is restricted to the diurnal dark period and is favoured by high temperatures. The interaction between the vernalization and dark inhibitory processes is such that in the absence of dark inhibition no vernalization is required by any strain, while on. the other hand sufficient vernalization can apparently overcome all dark inhibitory effects. Treatment with gibberellic acid eliminates the need for vernalization by plants of at least one early-flowering strain when. grown in short days at high temperatures. The strains of subterranean clover differ markedly in their responses to the three partial processes. In their response to the dark inhibitory process two strains are more affected by night temperature than by night length, while in two other strains the opposite is the case, which suggests that the dark inhibitory process could be resolved into more than one component.

Flower initiation in relation to maturity in crop plants. III. The flowering response of early and late cereal varieties to Australian environments

1966 ◽  
Vol 17 (1) ◽  
pp. 1 ◽  
Author(s):  
Y Aitken
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Leaf Number ◽  
Flower Initiation ◽  
Tropical Environments ◽  
Before And After ◽  
Delayed Initiation ◽  
Tropical Australia ◽  
The Difference ◽  
Early Flower

The difference between early- and late-flowering characters in wheat, rye, barley, and oats has been studied by growing some Australian and overseas varieties in several field environments with mean temperatures ranging from 10 to 22°C, and mean photoperiod of 10½ to nearly 16 hr, together with vernalization and prolonged photoperiod. Similar genotypes were found in each of the four cereals. Early varieties all flowered at a low leaf number, which showed that the genotypes for early flower initiation in these varieties are almost or entirely insensitive to temperature and photoperiod. In consequence, varieties with such genotypes can be expected to flower early, even in tropical Australia. In contrast, the genotypes for lateness caused initiation at a higher leaf number, and more sensitivity to temperature and photoperiod, both before and after flower initiation. Contrary to the common assumption that very late varieties need a period of cold followed by long photoperiod for flower initiation, they were found to initiate both in summer (i.e, high temperature) and in winter (low photoperiod) at Melbourne. High temperatures (above 15°C), however, delayed initiation, which resulted in flowering at a higher leaf number than when the same varieties were grown at low temperatures. In addition, the young reproductive shoot died after initiation in a combination of high temperature and a 14–12 hr photoperiod, as happens when such varieties are springsown in temperate latitudes. Such a response also prevents flowering in tropical environments, where high temperatures are combined with a moderate photoperiod all the year round.

Pre-maturation cold acquisition in Trifolium subterraneum

1974 ◽  
Vol 25 (6) ◽  
pp. 875 ◽  
Author(s):  
WJ Collins ◽  
DF Smith
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Seed Maturation ◽  
Flower Initiation ◽  
Appearance Time ◽  
Rate Of Development ◽  
Wide Range ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance ◽  
Different Levels

The influence of different levels of temperature during seed maturation on the subsequent rate of development in plants grown from that seed was studied in a range of subterranean clover cultivars. In one study the cultivars Carnamah, Yarloop, Woogenellup and Mt. Barker were grown at 7, 11, 14 and 17°C, and the seed produced grown on at 17°. Observations were made on the rate of leaf appearance, time of flower initiation, and time and node of first flowering. The rate of development was closely related to the temperature under which the seed was produced—the lower the temperature the faster was the rate of development. This effect was greatest with the later-flowering cultivars. In a second experiment, seed of a number of cultivars harvested commercially from a wide range of sites in southern Australia was grown on at 17°C and the rate of development observed. Time of flowering varied markedly between samples of only three cultivars. Accordingly seed of these samples were grown on for a further generation in a controlled environment. Within two of the cultivars, Mt. Barker and Bacchus Marsh, the differences in flowering observed in the previous generation persisted, which suggests that such differences were not based on environmental factors. In the cultivar Woogenellup the differences in flowering disappeared, which suggests that the original differences arose through different environmental conditions occurring during seed maturation. Cold acquisition in the maturing embryo does not seem to be a matter of practical consequence at present in subterranean clover, but may become so with changes in the location of seed production.

Flower initiation in pasture legumes. III. Flower initiation in Medicago tribuloides Desr. and other annual medics.

1955 ◽  
Vol 6 (2) ◽  
pp. 258 ◽  
Author(s):  
Y Aitken
Keyword(s):  
Low Temperature ◽  
Subterranean Clover ◽  
Late Summer ◽  
Flower Initiation ◽  
Commercial Variety ◽  
Barrel Medic ◽  
Pasture Legumes ◽  
Annual Medics ◽  
Long Photoperiod

Observations on barrel medic (Medicago tribuloides Desr., commercial variety) sown throughout the year in the field showed that the flower initiation of the winter sowings was the most rapid and that of the late summer sowings the most delayed. This delay was due to the absence of sufficiently low temperature following germination. Low temperature and long photoperiod accelerate flower initiation in barrel medic as in subterranean clover. Five types of annual medic that persist under Mallee conditions are similar in their flower initiation character to that of the "second-early" varieties of subterranean clover.

Low solubility of alumina in enstatite and uncertainties in estimated palaeogeotherms

1978 ◽  
Vol 288 (1355) ◽  
pp. 471-486 ◽  
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Alumina Content ◽  
Equilibrium Solubility ◽  
Low Solubility

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.

scholarly journals Environmental temperature during early life affects the personality of mosquitofish in adulthood

2021 ◽  
Author(s):  
Haifeng Li ◽  
Xinyu ZHang ◽  
Yi Wu ◽  
Feng ZHang ◽  
CHunlin Li
Keyword(s):  
Body Length ◽  
High Temperatures ◽  
Low Temperatures ◽  
Early Life ◽  
Environmental Temperature ◽  
Phenotypic Trait ◽  
Behavioral Syndrome ◽  
Growing Up ◽  
Female Fish ◽  
Behavioral Traits

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.

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