Carbon Dioxide Assimilation by Pineapple Plants, Ananas comosus (L.) Merr. II. Effects of Variation of the Day/Night Temperature Regime

1980 ◽  
Vol 7 (4) ◽  
pp. 375 ◽  
Author(s):  
TF Neales ◽  
PJM Sale ◽  
CP Meyer

The effects of variation of day/night temperature regime on the diurnal patterns of CO2 assimilation of pineapple plants were examined using single leaf and field enclosure methods. At day temperatures of 30°C, increasing night temperatures from 20 to 35°C reduced the total assimilation of CO2 per daily light/dark cycle from 6.5 to 1.3 g CO2 m-2 (leaf area) day-1, and also reduced the proportion of total CO2 assimilation that occurred at night from c. 90% to c. 40%. Decreasing day temperatures (30 to 10°C) had little effect on total daily CO2 assimilation in warm (25°C) nights, but reduced it in cooler (15°C) nights. At day temperatures of <152C, CO2 assimilation took place predominantly (60-100%) in the photoperiod. In cool (10°C) days, the normal inverted stomatal rhythm of CAM plants was reversed; leaf conductance was high (c. 1.0 mm s-1) throughout the photoperiod and a large CO2 efflux was observed, lasting c. 2 h, at the beginning of the dark period. Leaf conductance of pineapples, by day and by night, is strongly influenced by ambient temperatures, with cool conditions favouring stomatal opening.

1979 ◽  
Vol 59 (2) ◽  
pp. 469-473 ◽  
Author(s):  
R. G. INGRATTA ◽  
G. R. STEPHENSON ◽  
C. M. SWITZER

Optimum top growth of annual bluegrass (Pao annua L.) and Kentucky bluegrass (Poa pratensis L.) was obtained at 24/12 °C day/night temperature regime in controlled environment studies. The tolerance of seedling Kentucky bluegrass to linuron [3-(3,4-dichlorophenyl)-1)methylurea] appeared to be greatest at this temperature regime when photoperiods were 16 h in length. A granular formulation of linuron gave excellent control of annual bluegrass in Kentucky bluegrass turf at 6.7 kg/ha when applied postemergence. At this rate, all culitivars of Kentucky bluegrass tested, with the exception of Fylking, were tolerant to linuron as a granular formulation. After application of linuron at 3.4–6.7 kg/ha, phytotoxic residues remained in the soil at sufficient levels to injure seedling Kentucky bluegrass for up to 3 mo.


2005 ◽  
Vol 74 (4) ◽  
pp. 330-336 ◽  
Author(s):  
Satoshi Kubota ◽  
Junko Yamamoto ◽  
Yoko Takazawa ◽  
Hajime Sakasai ◽  
Kazuo Watanabe ◽  
...  

2004 ◽  
Vol 31 (12) ◽  
pp. 1195 ◽  
Author(s):  
Steffen M. Noe ◽  
Christoph Giersch

Modelling the diurnal course of photosynthesis in oak leaves (Quercus robur L.) requires appropriate description of the dynamics of leaf photosynthesis of which diurnal variations in leaf conductance and in CO2 assimilation are essential components. We propose and analyse a simple photosynthesis model with three variables: leaf conductance (gs), the CO2 partial pressure inside the leaf (pi), and a pool of Calvin cycle intermediates (aps). The environmental factors light (I) and vapour pressure deficit (VPD) are used to formulate a target function G(I, VPD) from which the actual leaf conductance is calculated. Using this gs value and a CO2 consumption term representing CO2 fixation, a differential equation for pi is derived. Carboxylation corresponds to the sink term of the pi pool and is assumed to be feedback-inhibited by aps. This simple model is shown to produce reasonable to excellent fits to data on the diurnal time courses of photosythesis, pi and gs sampled for oak leaves.


1983 ◽  
Vol 115 (8) ◽  
pp. 1039-1042 ◽  
Author(s):  
B. M. Hegdekar

AbstractThe critical photoperiod for diapause induction in pupae of Mamestra configurata Walker in Manitoba was 16 h 06 min at Glenlea (49°38′ N), 16 h 20 min at Grandview (51°10′ N), and 16 h 42 min at Birch River (52°24′ N). The differences in cirtical photoperiods observed at Glenlea and Grandview were not significant. At least two different photoperiods exist, one in the Glenlea and Grandview areas and the other in the Birch River area. In the laboratory, the critical photoperiod was 13.5 h when larvae were exposed to a daily fluctuating temperature regime of 12 h at 25 °C and 12 h at 10 °C. Longer critical photoperiods found for the field populations may be related to the relatively low ambient temperatures to which the larvae were exposed in field cages.


1994 ◽  
Vol 42 (2) ◽  
pp. 219 ◽  
Author(s):  
JS Day ◽  
BR Loveys ◽  
D Aspinall

The flowering responses of Boronia megastigma Nees (Rutacae) and Hypocalymma angustifolium Endl. (Myrtaceae) to different photoperiod and temperature regimes were similar despite the fact that these species are from different families. No flowers reached anthesis in a temperature regime of 25°C day/17°C night but flowering of both species occurred in a cool temperatures (17°C day/9°C night). Photoperiod had no effect on flowering at the temperatures tested. Ten weeks of cool temperatures (17°C day/9°C night) were required for a maximum number of flowers to reach anthesis on H. angustifolium plants whereas B. megastigma plants required 15 weeks. Flower development in both species was inhibited by a large difference between day and night temperature (21°C day/5°C night) and promoted if the day/night difference was reversed (9°C day/17°C night). The temperature of the aerial parts of the plant controlled flowering, whereas vegetative growth was controlled by root temperature. Therefore, while a reduction in vegetative growth naturally coincides with the production of flowers, these events are not necessarily linked.


1980 ◽  
Vol 7 (4) ◽  
pp. 363 ◽  
Author(s):  
PJM Sale ◽  
TF Neales

Net carbon exchange over 24-h cycles was measured in well watered pineapple plants, using a 'minicrop' in field assimilation chambers and single leaves in a growth cabinet. Whole plants under natural light and a standard 30°C day/15°C night regime showed crassulacean acid metabolism, nearly all assimilation occurring in the dark period, with a net efflux of CO2 in the day. Assimilation, as measured by both CO2 exchange and changes in titratable acidity in the leaf tissue, was markedly dependent on the total photosynthetically active radiation incident in the previous photoperiod. The molar ratio of the maximum acidity change to maximum net nocturnal CO2 influx was 1.8 : 1. The rate of deacidification depended on the irradiance in the current photoperiod. Efflux in the photoperiod was largely independent of irradiance, but was greater at very low irradiances. Maximum rates of CO2 assimilation in the minicrop were about 15 ng cm-2 (leaf area) s-1 in the dark at the standard temperature regime, and 22 ng-2 s-1 when photoperiod assimilation was induced by a 20°C day/30°C night regime. Similar rates were recorded in the single-leaf experiments, and are higher than those previously found for pineapple. Over a 24-h period, mean rates of about 6 ng cm-2 (leaf area) s-1 were recorded, in good agreement with measured dry weight changes over an extended period. These data help to explain earlier discrepancies in the literature between measured rates of CO2 assimilation and of crop growth rates in pineapples.


2005 ◽  
Vol 32 (5) ◽  
pp. 421 ◽  
Author(s):  
Liezel M. Gouws ◽  
C. Barry Osmond ◽  
Ulrich Schurr ◽  
Achim Walter

Distinct diel rhythms of leaf and cladode expansion growth were obtained in crassulacean acid metabolism (CAM) plants under water-limited conditions, with maxima at mid-day during phase III of CO2 assimilation. This pattern coincided with the availability of CO2 for photosynthesis and growth during the decarboxylation of malic acid, with maximum cell turgor due to the nocturnally accumulated malic acid, and with the period of low cytoplasmic pH associated with malic acid movement from vacuole to cytosol. Maximum growth rates were generally only 20% of those in C3 plants and were reached at a different time of the day compared with C3 plants. The results suggest that malic acid, as a source of carbohydrates, and a determinant of turgor and cytoplasmic pH, plays a major role in the control of diel growth dynamics in CAM plants under desert conditions. The observed plasticity in phasing of growth rhythms under situations of differing water availability suggests that a complex network of factors controls the diel growth patterns in CAM plants and needs to be investigated further.


Oecologia ◽  
1988 ◽  
Vol 75 (1) ◽  
pp. 99-104 ◽  
Author(s):  
B. I. L. Küppers ◽  
M. Küppers ◽  
E. -D. Schulze

1973 ◽  
Vol 26 (4) ◽  
pp. 705 ◽  
Author(s):  
TF Neales

The CO2 and water vapour fluxes arising from the tops of a plant of A. americana, growing in nutrient solution, were continuously measured at night temperatures of 15, 25, and 36�C, the day temperature being held constant at 25�C.


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