Stunting in 'Gigas' Wheat as Influenced by Temperature and Daylength

1986 ◽  
Vol 13 (3) ◽  
pp. 381 ◽  
Author(s):  
D Atsmon ◽  
MG Bush ◽  
LT Evans
Keyword(s):  
Shoot Apex ◽  
Wheat Line ◽  
Temperature Regimes ◽  
Pass Through ◽  
Short Days ◽  
Double Ridge

When plants of the uniculm 'gigas' wheat line 492 were grown at 15/ 10°C, all plants were severely stunted in long days (LD) but normal in short days (SD). The results of reciprocal transfers between SD and LD indicate that line 492 plants pass through a stage which is very sensitive to LD at 15/ 10°C, between about 14 and 27 days after sowing, just before double ridge formation at the shoot apex. LD during that interval caused stunting in most plants whereas SD at that stage allowed all plants to develop normally. Transfers between temperature regimes of 15/10°C and 24/19°C under LD also indicated that the period just prior to double ridge formation was critical for stunting. In the uniculm line 492 stunting in LD was caused by temperature regimes cooler than 21 /16°C;, whereas in the oligoculm line 380 the main shoots of most plants were normal even at 15/ 10°C.

Development of the shoot apex of blue spruce (Piceapungens)

1977 ◽  
Vol 7 (4) ◽  
pp. 614-620 ◽  
Author(s):  
Eric Young ◽  
James W. Hanover
Keyword(s):  
Shoot Apex ◽  
Continuous Light ◽  
Scale Formation ◽  
Seasonal Development ◽  
Bud Break ◽  
Blue Spruce ◽  
Bud Set ◽  
Significant Difference ◽  
Short Days ◽  
Needle Primordia

Blue spruce (Piceapungens Engelm.) seedlings grown in a nursery for 1 to 5 years and seedlings grown from seed in a greenhouse under continuous light for 2 to 6 months were studied to determine (1) time to bud set on transfer to short days, (2) time to bud-break on subsequent transfer to long days, and (3) the anatomy of the dormant shoot apex. Seasonal development of the shoot apex of a single 50-year-old blue spruce was also monitored.Time to but set on transfer to short days decreased after long periods under continuous light. Time to budbreak on subsequent transfer to long days increased with increasing age in nursery- and greenhouse-grown seedlings. The dormant shoot apex became more highly differentiated as the nursery-grown seedlings aged from 1 to 3 years, then showed no significant difference after 3 years of age.The 50-year-old blue spruce initiated many new needles in the current bud before bud scale formation, which began in mid-May. Needle primordia initiation in the new bud began in late June and slowed down in late August. Apical dome diameter increased and decreased concurrently with the increase and decrease in rate of needle primordia initiation.

Prediction of Frost Hardiness in Douglas Fir Seedlings by Measuring Electrical Impedance in Stems at Different Frequencies

1973 ◽  
Vol 3 (2) ◽  
pp. 256-264 ◽  
Author(s):  
R. van den Driessche
Keyword(s):  
Survival Data ◽  
Electrical Impedance ◽  
Douglas Fir ◽  
Frost Hardiness ◽  
Impedance Measurements ◽  
Temperature Regimes ◽  
Before And After ◽  
Post Test ◽  
Different Levels ◽  
Short Days

Frost hardiness of Douglas fir (Pseudotsugamenziesii Mirb. Franco.) plants was assessed by a range of freezing tests in three experiments. In experiments 1 and 2 plants were grown in different temperature regimes, under short days, for 8 weeks to induce different levels of frost hardiness. In experiment 3, plants remained in the open and were sampled on 21 occasions through one year.Comparison of stem impedance measurements made at 1 kHz, 4.5 kHz, and 1 MHz, before and after freezing tests in experiments 1 and 2, indicated survival of individual plants was well predicted by post test measurements. The postfreezing test 1 kHz/1 MHz ratio distinguished between dead and surviving plants with the smallest number of measurements. Both this ratio and 4.5 kHz impedance provided similar conclusions about treatment effects, which agreed satisfactorily with conclusions from survival data. Impedance ratios of 1 kHz/1 MHz measured in stems after freezing tests accurately predicted survival in experiment 3. Seasonal changes in ratio, determined after freezing to a particular temperature, paralleled seasonal change in plant frost hardiness and was significantly correlated with exposure to cold during 14 days prior to measurement.

Cold acclimation increases cold tolerance independently of diapause programing in the bean bug, Riptortus pedestris

2017 ◽  
Vol 108 (4) ◽  
pp. 487-493 ◽  
Author(s):  
J. Rozsypal ◽  
M. Moos ◽  
S.G. Goto
Keyword(s):  
Cold Acclimation ◽  
Cold Tolerance ◽  
Negative Impact ◽  
Riptortus Pedestris ◽  
Short Day ◽  
Cold Tolerant ◽  
Bean Bug ◽  
The Difference ◽  
Pass Through ◽  
Short Days

AbstractThe bean bug (Riptortus pedestris) is a pest of soybeans and other legumes in Japan and other Asian countries. It enters a facultative adult diapause on exposure to short days. While photoperiodism and diapause are well understood in R. pedestris, knowledge of cold tolerance is very limited, as is information on the effect of diapause on cold tolerance. We examined the effect of photoperiod, cold acclimation, and feeding status on cold tolerance in R. pedestris. We found that cold acclimation significantly increased survival at −10°C in both long- and short-day adult R. pedestris. Since the difference in cold survival between long- and short-day cold-acclimated groups was only marginal, we conclude that entering diapause is not crucial for R. pedestris to successfully pass through cold acclimation and become cold tolerant. We observed similar effects in 5th instar nymphs, with both long- and short-day cold-acclimated groups surviving longer cold exposures compared with non-acclimated groups. Starvation, which was tested only in adult bugs, had only a negligible and negative impact on cold survival. Although cold tolerance significantly increased with cold acclimation in adult bugs, supercooling capacity unexpectedly decreased. Our results suggest that changes in supercooling capacity as well as in water content are unrelated to cold tolerance in R. pedestris. An analysis of metabolites revealed differences between the treatments, and while several metabolites markedly increased with cold acclimation, their concentrations were too low to have a significant effect on cold tolerance.

Effects of Higher Temperatures, Photoperiod and Seed Vernalisation on Development in Two Spring Wheats

1993 ◽  
Vol 20 (2) ◽  
pp. 211 ◽  
Author(s):  
HM Rawson ◽  
M Zajac
Keyword(s):  
Published Data ◽  
Floral Initiation ◽  
Complex Interactions ◽  
Increased Temperature ◽  
Temperature Regimes ◽  
Controlled Environments ◽  
Higher Temperature ◽  
Source Limitation ◽  
Long Photoperiod ◽  
Short Days

The intention of this work was to examine to what degree development in wheat is modified by increased temperature when other environmental factors are also varied. The genotypes used were an early season wheat, Hartog, and a closely related mid-season line, Late Hartog. Plants were grown throughout in temperature regimes of 25/15�C or 17/7�C and photoperiods of 9, 11, 13 or 15 h with 9 h of natural summer radiation. Seeds were vernalised for 0, 2 or 4 weeks. Increased temperature extended the thermal time to ear emergence, particularly in Late Hartog, and particularly under short days after plants had been vernalised for 4 weeks. Phyllochron intervals on the main shoot were increased by higher temperature, as were spikelet numbers in Late Hartog under long photoperiod. However, in Hartog and in Late Hartog exposed to short days, spikelet numbers were reduced by increased temperature. Long seed vernalisation significantly reduced leaf and spikelet number in Late Hartog but only at the higher temperature. Fewer spikelets were produced per leaf at short photoperiod. The apparently complex interactions between temperature, photoperiod, genotype, and seed vernalisation on development are explained in terms of their effects on the timing of floral initiation and the related numbers of primordia accumulated on the apex at that stage. We hypothesise that, in the absence of source limitation, delays in floral initiation such as occur through shortening of photoperiod can increase numbers of leaves and spikelets, though at a decreasing rate with increasing delay. When source is limiting, as under higher temperature and unchanged or reduced radiation, long delays result in a greater reduction in the rate of production of organs and their final number. We further propose that much of the change may be associated with the interplay between the plastochron and phyllochron intervals. Published data are examined to show that high temperatures delay ear emergence in other genotypes both in controlled environments and in the field.

Differential Effects of Temperature on Floral Development and Sucrose Content of the Shoot Apex of Wheat

1983 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
PK Mohapatra ◽  
D Aspinall ◽  
CF Jenner
Keyword(s):  
High Temperature ◽  
Shoot Apex ◽  
Growth And Development ◽  
Floral Development ◽  
Sucrose Concentration ◽  
Dry Weight ◽  
Relative Growth ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Double Ridge

The effects of high temperature on the growth and development of the shoot apex of wheat, cv. Warimba, growing in a short photoperiod (8 h) were examined. High temperature (30°C) from germination onwards delayed the initiation of double ridges on the apex in comparison to low temperature (20°C) but did not affect the subsequent rate of spikelet development to stamen initiation. The rate of primordium production on the apex was reduced at the higher temperature and there was a decrease in the final number of spikelets produced. The growth in dry weight of both the shoot and apex was reduced at the higher temperature, but the relative growth rate of the apex was unaffected after double-ridge initiation. The sucrose concentration in the shoot apex tended to be higher at the higher temperature and so it was concluded that the effects of exposure to high temperature on apex growth were not mediated through effects on assimilate supply.

scholarly journals Inflorescence Initiation in Lolium Temulentum L. IV. Translocation of the Floral Stthiulus in Relation to that of Assimilates

1964 ◽  
Vol 17 (1) ◽  
pp. 1 ◽  
Author(s):  
LT Evans ◽  
IFW ardlaw
Keyword(s):  
Shoot Apex ◽  
Small Proportion ◽  
Inhibitory Effect ◽  
Lolium Temulentum ◽  
Long Day ◽  
Short Days

Translocation of labelled assimilates to the shoot apex and other parts of the plant was followed from an upper leaf held in long-day conditions, when lower leaves in short days were either present or removed. Similarly a comparison was made of the distribution of assimilates from an upper long-day leaf and a lower leaf held in short days. The presence of lower leaves did not reduce the movement of assimilates from the upper leaf to the shoot apex, and the lower leaf supplied only a small proportion of the assimilates reaching the shoot apex, although it supplied much to the roots. It is concluded that the previously established inhibitory effect of lower leaves in short days on inflorescence initiation in L. temulentum is unlikely to be due to their interference with translocation of the long-day stimulus to the shoot apex, or to their diluting it with assimilates, but rather to their production of a transmissible inhibitor of initiation.

Accumulation of food reserves in cottonwood stems during dormancy induction

1981 ◽  
Vol 11 (1) ◽  
pp. 145-154 ◽  
Author(s):  
Eric A. Nelson ◽  
Richard E. Dickson
Keyword(s):  
Stem Elongation ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Tissue Samples ◽  
Starch Concentration ◽  
Total Nonstructural Carbohydrates ◽  
Temperature Regimes ◽  
Food Reserves ◽  
Dormancy Induction ◽  
Short Days

Early chemical storage as related to growth changes that occur in cottonwood (Populusdeltoides Bartr. ex. Marsh) stems during dormancy induction was investigated. In this experiment, plant dormancy was induced by 8-h photoperiods (short days) and 20 °C: 14 °C temperature regimes. Tissue samples were taken at four stem positions for 8 weeks under short days. Leaf expansion and stem elongation had stopped by the 4th week under short days, and terminal buds had formed. Starch concentration in the lower stem began to increase during the 3rd week and continued throughout the dormancy induction period. By the 8th week starch concentration in the stem was about 24% residue dry weight (RDW). Total nonstructural carbohydrates (starch and soluble sugars) increased almost linearly after the 1st week to about 38% RDW. Free amino acids increased during the first 2 weeks to 1.6%, declined to 0.2% by 6 weeks, then remained constant. Triglyceride concentration remained level for the first 2 to 3 weeks, then increased from 1 to 3% RDW. Changes in the various chemical fractions were sequential and associated with different phases of dormancy induction. Cottonwood, although previously considered a "fat-storing" tree based on histochemical analyses of winter food reserves, stores primarily carbohydrate. Carbohydrate is stored initially as starch and then converted to soluble sugars under cold conditions.

The influence of temperature on flowering in species of Lolium and in Poa pratensis

1960 ◽  
Vol 54 (3) ◽  
pp. 410-416 ◽  
Author(s):  
L. T. Evans
Keyword(s):  
Poa Pratensis ◽  
Cold Treatment ◽  
Continuous Light ◽  
Response Curves ◽  
Short Rotation ◽  
Rate Limiting Step ◽  
Temperature Regimes ◽  
Influence Of Temperature On ◽  
Night And Day ◽  
Short Days

The influence of various night- and day-temperature regimes on inflorescence initiation and earing in vernalized and unvernalized Lolium temulentum, L. multiflorum, short-rotation ryegrass, and two varieties of L. perenne, and also in the Athabasca strain of Poa pratensis, is described.Vernalization response curves for the ryegrasses, when grown under controlled conditions, are presented, and are consonant with the operation of a first-order reaction as the rate-limiting step in the vernalization ofLolium perenne. Velocity coefficients for the rate of vernalization in various conditions are deduced, and are shown to be higher in seedlings than in seeds, and higher in short days at 10° C. than at 4° C. The Q 10 for the velocity of vernalization over this range is about 2·7.Low-temperature vernalization in L. perenne can occur when low night temperatures are combined with moderately high day temperatures, and it can take place during abundant vegetative growth. In short days and in continuous light mean temperatures up to 10° C, at least, are fully effective, but in 16 hr. photoperiods even 7° C. was not a fully effective vernalizing temperature. The requirement of perennial ryegrass plants for cold treatment may be replaced by short-day induction if light intensities are low and if the plants are continually divided.

Timing in Chenopodium rubrum of export of the floral stimulus from the cotyledons and its action at the shoot apex

1972 ◽  
Vol 50 (4) ◽  
pp. 697-702 ◽  
Author(s):  
R. W. King
Keyword(s):  
Cell Division ◽  
Mitotic Index ◽  
Shoot Apex ◽  
Essential Role ◽  
Floral Development ◽  
Dark Period ◽  
Chenopodium Rubrum ◽  
Floral Stimulus ◽  
Dividing Cells ◽  
Short Days

When the cotyledons of 6-day-old seedlings of Chenopodium rubrum were removed at various intervals after exposure to a single 13.5-h dark period, defoliation during the first 6 h after darkness prevented flowering. If the cotyledons remained on the plant for a further 5 or more hours flowering gradually increased. Within 20 h after the end of the dark period, the cotyledons had completed their essential role and subsequent defoliation had no influence on flowering. A cotyledon area of about 30 mm2 was required for maximal floral induction.It can be concluded that a transmissible factor—often termed floral stimulus—was produced in the cotyledons following a short-day exposure. It is also apparent that flowering in Chenopodium rubrum depends on the generation of a floral stimulus in short days, rather than on control by a transmissible inhibitor of flowering produced under long days.After arrival of the floral stimulus at the apex there was a doubling from 2% to 4% in the percentage of cells undergoing mitosis. This increased value of the mitotic index was maintained during floral development and probably reflected an increased rate of cell division. There were rapid and sometimes rhythmic fluctuations in the percentage of dividing cells.

scholarly journals ABSCISIC ACID LEVELS AND INFLORESCENCE ABORTION IN HELICONIA STRICTA

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 576b-576
Author(s):  
Setapong Lekawatana ◽  
Richard A. Criley
Keyword(s):  
Abscisic Acid ◽  
Light Intensity ◽  
Indirect Elisa ◽  
Economic Loss ◽  
Separate Experiment ◽  
Night Temperature ◽  
Inflorescence Development ◽  
Temperature Regimes ◽  
Abscisic Acid Level ◽  
Short Days

Inflorescence abortion in heliconia contributes to an economic loss to growers. In an effort to determine the cause, we manipulated temperature, daylength and light intensity. Plants of Heliconia stricta cv. Dwarf Jamaican were grown in 4 day/night temperature regimes (15/10, 20/15, 25/20 and 30/25°C) under 14 hr daylength. In a separate experiment, plants were grown in full sun, 60% and 80% shade. Both experiments had been conducted after inflorescences were induced (4 weeks of short days). Apical meristems were dissected weekly to follow inflorescence development. Leaf abscisic acid level was detected by an indirect ELISA. Significantly more inflorescences were aborted in plants grown under high temperature regimes than in plants grown under low temperature regimes and under different light intensity. Abscisic acid concentration increased in heliconia leaves under regimes that induced inflorescence abortion. The results could provide a mean to improve heliconia inflorescence production.

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