scholarly journals Temperature and Irradiance Effects on Vegetative Growth of Two Species of Leucocoryne

2003 ◽  
Vol 128 (6) ◽  
pp. 815-820
Author(s):  
J.L. Catley
Keyword(s):  
Vegetative Growth ◽  
Low Temperatures ◽  
Controlled Environment ◽  
Plant Parts ◽  
Leaf Emergence ◽  
Mean Temperature ◽  
Made In

The influences of temperature and irradiance on vegetative growth of two species of Leucocoryne (Leucocoryne coquimbensis F. Phil and L. ixioides (Hook.) Lindl.) were examined in controlled environment growth rooms. The growing environments had day/night temperatures of 10/5, 15/10, or 20/15 °C, providing mean temperatures of 7.5, 12.5, or 17.5 °C, and photosynthetic photon fluxes (PPF) of 497 or 710 μmol·m-2·s-1. Leaf emergence data were recorded up to three times a week, and measurements of vegetative growth were made in the rooms twice weekly. Destructive harvests were carried out at intervals up to four weeks apart. Leaves of L. ixioides emerged first in all mean temperatures. As mean temperature decreased from 17.5 to 7.5 °C, the differences in first emergence dates became more apparent between species. Appearance of the second leaf of both species occurred in less than half the number of days the first leaf took to emerge. The time taken for further leaves to develop increased as temperature decreased, particularly for L. ixioides and at mean temperatures below 12.5 °C. Although leaves of L. ixioides emerged first, days to emergence of further leaves increased to lag behind production of L. coquimbensis leaves, particularly when mean temperatures dropped below 12.5 °C. Temperature also significantly affected growth of other plant parts. As mean temperature increased, maximum leaf, root and main bulb dry weights increased for both species, along with secondary bulb dry weights of L. coquimbensis. As irradiance increased, maximum leaf dry weights decreased and maximum bulb dry weights increased of both species, and maximum dropper dry weights of L. coquimbensis increased. Leucocoryne coquimbensis appears to have the greatest capacity to multiply vegetatively and this is enhanced by high mean temperatures. These results suggest that mean temperatures higher than those used in this study are required for sustained leaf emergence, particularly for L. ixioides although this species has the capacity to emerge at low temperatures. High mean temperatures are also likely to promote vegetative mass of all plant parts of both species, whereas higher irradiance levels than used in this study would enhance main bulb growth.

Hydrographic and nutrient chemistry surveys in the western English channel during 1963 and 1964

1972 ◽  
Vol 52 (4) ◽  
pp. 915-930 ◽  
Author(s):  
F. A. J. Armstrong ◽  
E. I. Butler ◽  
G. T. Boalch
Keyword(s):  
Suspended Matter ◽  
Low Temperatures ◽  
English Channel ◽  
Nitrogen And Phosphorus ◽  
Mean Values ◽  
Average Temperature ◽  
Significant Difference ◽  
Nutrient Chemistry ◽  
Phosphate Silicate ◽  
Made In

Three surveys were made in 1963 and five in 1964 in the area of the English Channel between the English and French coasts and between 3° 40' W and 5°10' W. This area had been surveyed in 1961 and 1962. Temperature and salinity were determined at o, to and 50 m and phosphate silicate and nitrate at 10 and 50 m. The results are presented graphically. Temperature and salinity were compared with Lumby's 25–year averages. The year 1963 started with unusually low temperatures and salinities higher than average. Temperature remained low in the spring, but salinity decreased. The year 1964 started with temperatures and salinities above normal, but during the rest of the year values were close to average. Nitrate in January 1964 was higher than in January 1963. Analyses of suspended matter at 12m were made for carbon, nitrogen and phosphorus on most surveys, and mean values for the whole area are given. Suspended carbon was 67 /ig C/l. in January 1963 and 51 /*g C/l. in January 1964, a significant difference. Increases in sus-pended carbon, nitrogen and phosphorus were found in spring and summer 1964.

Studies on the storage of potatoes II. The temperature conditions inside potato clamps

1950 ◽  
Vol 40 (3) ◽  
pp. 199-226 ◽  
Author(s):  
E. M. Crook ◽  
D. J. Watson
Keyword(s):  
Air Temperature ◽  
Heat Production ◽  
First Year ◽  
Temperature Conditions ◽  
Mean Temperature ◽  
The Difference ◽  
Made In

Continuous records of the temperature of potatoes stored in clamps were made in 1942–3 (one clamp) and in 1943–4 (three clamps). In the first year, the temperatures at various positions in the clamp coverings were also recorded.The temperature at the middle of the potato heap showed a drift with time similar to that of mean air temperature. Deviations of mean air temperature from smooth trend, lasting for about a week, had no effect on the temperature of the potatoes; longerperiod deviations were reflected in the temperature of the potatoes after a lag of about a week. The difference in weekly mean temperature between potatoes and external air averaged about 1–5° C. in 1943–4. In 1942–3 it was greater, increasing to over 20° C. in April, because bacterial rotting of the potatoes following blight infection increased the rate of heat production and caused the clamp to collapse at the end of April.

Controlled-temperature effects on cotton growth and development

1998 ◽  
Vol 130 (4) ◽  
pp. 451-462 ◽  
Author(s):  
D. ROUSSOPOULOS ◽  
A. LIAKATAS ◽  
W. J. WHITTINGTON
Keyword(s):  
Leaf Area ◽  
Temperature Variation ◽  
Vegetative Growth ◽  
Growth And Development ◽  
Dry Weight ◽  
Maximum Temperature ◽  
Node Number ◽  
Mean Temperature ◽  
Fruiting Branch ◽  
Threshold Temperatures

The growth and development of cotton was studied on cotton plants grown in pots in growth rooms under constant day/night temperature (C) and varying temperature regimes throughout the day and/or night (V) The V-treatments had a common mean temperature of 22°C. The objectives were to determine the thermal requirements of three cultivars and to observe the extent of genotype×thermal environment interactions throughout the entire growth period.Vegetative growth was found to be almost exclusively time and temperature dependent, varietal differences being largely insignificant. Plant material was found to accumulate four times faster under the warmest C-regime, which was 7°C warmer than the coolest. The C-treatments caused variation in the number and size of lateral shoots and leaves, causing leaf area to be larger at the squaring stage in cool environments but at maturity in warm regimes. Relatively cool nights lowered the position of the first floral or fruiting branch, whereas warm days shortened flowering intervals and thus promoted earliness. However, the effect of temperature in altering the position of the first floral branch seems to be less important than its effect on the shedding of early squares.The effects of fluctuating temperature (V) on vegetative growth and earliness were similar to those from constant temperature environments. Growth and development rates were low in the low minimum V-regimes, especially when the maximum temperature was also low. Temperature variation affected vegetative growth to a greater extent in the early than in the later stages of development. At squaring, leaf area and dry weight were lowest under the regime with the highest minimum and maximum temperatures. Later on, only leaf area at flowering and total dry weight at maturity significantly differed between treatments. High maximum or minimum temperatures produced effects similar to a higher or lower mean temperature, respectively. The low minimum raised the node number of the first floral or fruiting branch, whereas in the case of boll dry weight it acted in the same way as a further drop in temperature, decreasing the weight, regardless of the maximum temperature. Boll period was affected mainly by the temperature variation itself rather by than the type of variation.The inverse of time to a certain stage and the corresponding mean temperature were linearly related and allowed threshold temperatures (T0) and thermal time requirements to be estimated. T0=12°C, except for the initial stage, when it was lower. A cotton growing season cooler on average by only 1°C will considerably delay maturity.

scholarly journals Nucleation and Grain Growth in Interstellar Space

1965 ◽  
Vol 7 ◽  
pp. 191-206
Author(s):  
Bertram Donn
Keyword(s):  
Grain Growth ◽  
Chemical Reactions ◽  
Low Temperatures ◽  
Stellar Atmospheres ◽  
Interstellar Space ◽  
Considerable Influence ◽  
Direct Bearing ◽  
Interstellar Grains ◽  
Made In

The First Detailed Studies to determine the processes by which interstellar grains may form were made by a group of Dutch astronomers in the 1940's. (See refs. 1 to 5.) Since that time very little systematic work on this problem has been done until very recently when Hoyle and Wickramasinghe (ref. 6) investigated graphite formation in cool stellar atmospheres. Van de Hulst's paper in 1949 (ref. 5) represents the culmination of an intensive attack which had considerable influence on astronomical thought about interstellar grains.Somewhat ironically, beginning about 1949 many significant advances in physics and chemistry having a direct bearing on this problem were made. In 1949, Frank in reference 7 presented a theory which explained how real crystals tend to grow, and much work, both theoretical and experimental, has been done since then. (See ref. 8.) Recent extensive research in chemical reactions at low temperatures both in solids and on surfaces is reported in reference 9.

Hemp Dogbane Growth and Control

Weed Science ◽  
1972 ◽  
Vol 20 (2) ◽  
pp. 156-159 ◽  
Author(s):  
Laren R. Robison ◽  
Larry S. Jeffery
Keyword(s):  
Seed Germination ◽  
Soil Type ◽  
Vegetative Growth ◽  
Soil Cover ◽  
Seedling Emergence ◽  
Control Seed ◽  
Cover Soil ◽  
And Control ◽  
Emergence Response ◽  
Made In

Hemp dogbane (Apocynum cannabinum L.) was investigated relative to seed germination, depth of seedling emergence, response to clipping, influence of soil type and fertility on vegetative growth, and herbicidal control. Seed germination in this study was influenced by light and scarification. Seedling emergence was influenced by the amount of soil cover. Soil type and fertility affected vegetative growth. In a greenhouse clipping study, hemp dogbane became perennial 41 days after emergence and by 65 days was producing more than one shoot per plant following clipping. Hemp dogbane was more completely controlled following September application of herbicide than from application made in June.

Environment and Bromoxynil Phytotoxicity

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 101-105 ◽  
Author(s):  
John D. Nalewaja ◽  
Grzegorz Skrzypczak
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Low Temperatures ◽  
Practical Importance ◽  
Amaranthus Retroflexus ◽  
Controlled Environment ◽  
Growth Stages ◽  
Redroot Pigweed ◽  
Wild Mustard ◽  
Simulated Rain

Experiments in controlled-environment chambers indicated that high temperature, 30 C, increased the phytotoxicity of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) to wild mustard (Sinapis arvensisL. # SINAR) and redroot pigweed (Amaranthus retroflexusL. # AMARE) compared to low temperature, 10 C, during and after treatment. Bromoxynil phytotoxicity generally was higher at relative humidities of 90 to 95% compared to 40 to 60%, but relative humidity had less influence on bromoxynil phytotoxicity than did temperature. A simulated rain immediately after bromoxynil treatment reduced control of both species, but the reduction was of no practical importance for wild mustard. The data indicate that wild mustard and redroot pigweed control would be reduced by bromoxynil application during a period of low temperatures or to plants in advanced growth stages.

Viewing Plant Systematics through a Lens of Plant Compensatory Growth

2010 ◽  
Vol 72 (9) ◽  
pp. 541-544 ◽  
Author(s):  
Roy V. Rea ◽  
Hugues B. Massicotte
Keyword(s):  
Vegetative Growth ◽  
Compensatory Growth ◽  
Mechanical Damage ◽  
Plant Response ◽  
Plant Systematics ◽  
Plant Identification ◽  
Plant Parts ◽  
Identification Keys ◽  
Normal Ranges ◽  
Underlying Processes

Plant compensatory growth is a phenomenon of exaggerated vegetative growth that occurs in plants as a result of mechanical damage (e.g., cutting or browsing). Because shoots, leaves, and other plant parts grow larger on plants undergoing compensation, they typically fall outside of the normal ranges given in plant identification keys and confuse students who are attempting to classify them. Here, we describe the conundrum faced by students collecting compensatory materials and offer suggestions on how to help students identify their ““plant-in-hand”” and how to seize a teaching moment to examine and explain the underlying processes that lead to this fascinating plant response.

A greater relative growth rate of Brassica rapa L. at low temperatures increases biomass at anthesis

2001 ◽  
Vol 52 (6) ◽  
pp. 645 ◽  
Author(s):  
P. Si ◽  
N. Thurling
Keyword(s):  
Growth Rate ◽  
Brassica Rapa ◽  
Seed Yield ◽  
Negative Correlation ◽  
Low Temperatures ◽  
Leaf Tissue ◽  
Dry Weight ◽  
Controlled Environment ◽  
Relative Growth ◽  
Potassium Leakage

0t, n.s.). These relationships suggested that it might be possible to develop early flowering cultivars with increased seed yield by selecting for higher RGR before anthesis. RGR of BC 2 F 3:4 lines in the field during winter was correlated with RGR at low temperatures (13/4°C) in a controlled environment, suggesting that genotypes producing more dry weight at anthesis grew more at the low temperatures normally experienced in the field. This was supported by a significant (P < 0.05 0.05) negative correlation (r = –0.69**) between growth in the field and potassium leakage from leaf tissue at 4

Resistance to water flow through leaves of Coffea arabica is dominated by extra-vascular tissues

2004 ◽  
Vol 31 (12) ◽  
pp. 1161 ◽  
Author(s):  
Antonio Gascó ◽  
Andrea Nardini ◽  
Sebastiano Salleo
Keyword(s):  
Low Temperatures ◽  
Coffea Arabica ◽  
Vascular System ◽  
Membrane Damage ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Flow Through ◽  
Frame Work ◽  
Coffea Arabica L ◽  
Made In

The leaf hydraulic conductance (Kleaf) of Coffea arabica L. was measured for shoots exposed to non-lethal temperature stress or to a freeze–thaw cycle, and compared with Kleaf of non-stressed samples (controls). Exposure to temperatures below 6°C for 1 h caused measurable damage to the functional integrity of cell membranes as shown by increased membrane leakiness to electrolytes. A 1 : 1 relationship was found to exist between relative electrolyte leakage and relative Kleaf suggesting that membrane damage caused Kleaf to increase. Low temperatures did not cause membrane disruption as shown by the comparison of chilled samples with frozen–thawed ones. In frozen leaves, membranes were extensively disrupted and both electrolyte leakiness and Kleaf increased 5-fold. Low temperatures did not induce alterations of the hydraulic properties of the leaf vascular system, as revealed by measurements of Kleaf after up to 500 cuttings of minor veins were made in the leaf blade of control and chilled leaves. Calculations showed that 62–75% of leaf hydraulic resistance resided in the extra-vascular water pathway. Results are discussed within the frame work of our current understanding of leaf hydraulic architecture as well as in terms of plant adaptation to extremes in temperature.

Nitrogen supply controls vegetative growth, biomass and nitrogen allocation for grapevine (cv. Shiraz) grown in pots

2015 ◽  
Vol 42 (1) ◽  
pp. 105 ◽  
Author(s):  
Aurélie Metay ◽  
Jessica Magnier ◽  
Nicolas Guilpart ◽  
Angélique Christophe
Keyword(s):  
Vegetative Growth ◽  
Limiting Factor ◽  
Dependent Manner ◽  
Leaf Emergence ◽  
N Supply ◽  
Secondary Axis ◽  
Axis Elongation ◽  
Primary Axis ◽  
N Deficiency ◽  
Area Expansion

Maintaining grapevine productivity with limited inputs is crucial in Mediterranean areas. Apart from water, nitrogen (N) is also an important limiting factor in grape growing. The effects of N deficiency on grapevine growth were investigated in this study. Two-year-old Vitis vinifera L.cv. Shiraz plants grafted on 110 R were grown in pots placed outside and exposed to various N supplies (0, 0.6, 1.2, 2.4 and 12 g plant–1) under well-watered conditions. At veraison, plants were harvested and organs separately dried, weighed and analysed for N. During plant growth, the length of the primary and secondary axes and the number of leaves on them were recorded. The N content of leaves was also analysed at three phenological stages (flowering, bunch closure and veraison). All growth processes were inhibited by N deficiency in an intensity-dependent manner. Quantitative relationships with N supply were established. Vegetative growth responded negatively to N stress when comparing control N supply with no N supply: primary axis elongation (–61%), leaf emergence on the primary axis (–47%), leaf emergence on the secondary axis (–94%) and lamina area expansion (–45%). Significant differences on the plant N status were observed from flowering onwards which might be useful for managing fertilisation.

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