scholarly journals Studies on Matter Production of Edible Canna (Canna edulis Ker.). IV. Leaf unrolling and changes in leaf photosynthetic rates with growth under field conditions.

1996 ◽  
Vol 65 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Morio KATO ◽  
Katsu IMAI
Keyword(s):  
Field Conditions ◽  
Photosynthetic Rates ◽  
Matter Production ◽  
Leaf Unrolling

scholarly journals Physiological and Biochemical Response of Winter Wheat (Triticum Aestivum L.) to Ambient O3 and the Antiozonant Chemical Ethylenediurea (EDU) in Jeddah, Saudi Arabia

2018 ◽  
Vol 11 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Laila A. Baqasi ◽  
Huda A. Qari ◽  
Ibrahim A. Hassan
Keyword(s):  
Triticum Aestivum ◽  
Stomatal Conductance ◽  
Growth Yield ◽  
Growing Season ◽  
Triticum Aestivum L ◽  
Field Conditions ◽  
Growth And Yield ◽  
Photosynthetic Rates ◽  
Promising Tool ◽  
Physiological And Biochemical

This study was to conducted to investigate the use of ethylenediurea (EDU) as a possible tool to evaluate O3 effects on wheat (Triticum aestivum L.) plants under field conditions in Jeddah. Wheat plants were expsoed to ambient O3 (AA) and the antiozonant chemical ethylenediurea (EDU) in closed fumigation chambers for the full growing season. Growth, yield and physiology were determined in response to O3 and/or EDU. EDU-treated plants had higher photosynthetic rates (24%) and stomatal conductance (25%), which were reflected in higher growth and yield in terms of number of grains. The present study revealed that EDU could be used as a promising tool to mitigate damaging effects of O3 on under field conditions. EDU protected wheat plants leading to increases in photosynthetic rates, growth and yield.

Effects of ambient ozone on the productivity of Populustremuloides Michx. grown under field conditions

1986 ◽  
Vol 16 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Deane Wang ◽  
David F. Karnosky ◽  
F. Herbert Bormann
Keyword(s):  
Leaf Senescence ◽  
Dry Matter ◽  
Field Experiments ◽  
Ambient Air ◽  
Air Pollutant ◽  
Field Conditions ◽  
Rural Site ◽  
Ambient Ozone ◽  
Foliar Symptoms ◽  
Matter Production

Field experiments were conducted at a rural site in Millbrook, NY, to measure effects of ambient ozone on saplings of Populustremuloides Michx. Over a 3–year period, four clones representing a range of pollutant sensitivities were exposed to charcoal-filtered and ambient air in open-top chambers. Ambient ozone significantly reduced (12–24%) aboveground dry-matter production and modified tree morphology, root/shoot ratios, and rates of leaf senescence. For two clones, biomass was reduced without visible foliar symptoms. This response raises the possibility of widespread, asymptomatic depression of forest productivity under ambient air pollutant conditions.

Photothermal time describes common ragweed (Ambrosia artemisiifoliaL.) phenological development and growth

Weed Science ◽  
1998 ◽  
Vol 46 (5) ◽  
pp. 561-568 ◽  
Author(s):  
William Deen ◽  
L. Anthony Hunt ◽  
Clarence J. Swanton
Keyword(s):  
Leaf Area ◽  
Mechanistic Model ◽  
Field Conditions ◽  
Total Biomass ◽  
Common Ragweed ◽  
Matter Production ◽  
Growth Room ◽  
Time Accumulation ◽  
The Relationship ◽  
Crop Competition

The ability to predict weed phenological development under field conditions is fundamental to the development of mechanistic weed–crop competition models. We studied how phenological development of common ragweed grown under field conditions could be explained using temperature and photoperiod responses derived from growth room experiments. We also determined the relationship between phenological development and common ragweed leaf area, dry matter production, and partitioning. Phenological development of common ragweed emerging at different times in the field was described by photothermal time based on temperature and photoperiod responses derived from growth room experiments. Estimated dates of phenological events of common ragweed were within 4 d of recorded values. Common ragweed seedling density did not influence phenological development. Common ragweed leaf area development, biomass partitioning, and total biomass were related to photothermal time accumulation. The results of this study are consistent with our hypothesis that phenological development is a major factor influencing the outcome of weed–crop competition. Results obtained from this study can be incorporated into a mechanistic model of weed–crop competition.

Selection and evaluation of root nodule bacteria for Dorycnium spp.

2005 ◽  
Vol 45 (3) ◽  
pp. 241 ◽  
Author(s):  
S. R. Davies ◽  
J. G. Howieson ◽  
R. J. Yates ◽  
P. A. Lane
Keyword(s):  
Dry Matter ◽  
Root Nodule ◽  
Field Conditions ◽  
Low Fertility ◽  
Sand Culture ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Pasture Legumes ◽  
Matter Production ◽  
Perennial Legumes

Dorycnium spp. are perennial legumes that have the ability to produce a source of forage in low fertility soils under low rainfall conditions. The inoculation of Dorycnium spp. is currently with the commercial Lotus corniculatus inoculant SU343, which until now had not been trialed against a range of alternative inoculants for Dorycnium spp. A glasshouse trial in sterile sand culture was conducted with 3 species of Dorycnium spp. along with 6 important pasture legumes to evaluate nitrogen-fixing performance, and host and rhizobia interactions. Several inoculants were selected from this trial to undergo evaluation under Tasmanian field conditions. The dry matter production of Dorycnium spp. in the glasshouse and field indicated that SU343 is a suitable inoculant for this genus. A Tasmanian isolate (WSM2338) was identified as a complimentary strain for the inoculation of Dorycnium spp., however, negative interactions with important pasture legumes require further investigation.

scholarly journals Growth, Carbon Acquisition, and Source-Sink Relationships in `Titan' Red Raspberry

1994 ◽  
Vol 119 (6) ◽  
pp. 1163-1168 ◽  
Author(s):  
Gina E. Fernandez ◽  
Marvin P. Pritts
Keyword(s):  
Accumulation Rate ◽  
Light Response ◽  
Dry Weight ◽  
Rubus Idaeus ◽  
Field Conditions ◽  
Partial Recovery ◽  
Red Raspberry ◽  
Response Curves ◽  
Photosynthetic Rates ◽  
Light Response Curves

Seasonal changes in growth, mean maximal photosynthetic rates, and the temperature and light response curves of `Titan' red raspberry (Rubus idaeus L.) were obtained from potted plants grown under field conditions. Primocane dry weight accumulation increased steadily at the beginning and the end of the season, but growth slowed midseason during fruiting. The slower midseason dry-weight accumulation rate coincided with an increase in root dry weight. Primocane net assimilation rate (NAR) was highest early in the season. Floricane photosynthetic rates (A) were highest during the fruiting period, while primocane A remained steady throughout the season. Primocane and floricane leaflets displayed a midday depression in A under field conditions, with a partial recovery in the late afternoon. Photosynthetic rates of primocane and floricane leaves were very sensitive to temperature, exhibiting a decline from 15 to 40C. Light-response curves differed depending on cane type and time of year. A temporal convergence of sink demand from fruit, primocanes, and roots occurs when plants experience high temperatures. These factors may account for low red raspberry yield.

Alteration of size of wheat root systems and nitrogen fixation by associative nitrogen-fixing bacteria measured under field conditions

1988 ◽  
Vol 34 (6) ◽  
pp. 735-739 ◽  
Author(s):  
R. M. N. Kucey
Keyword(s):  
Plant Root ◽  
N Uptake ◽  
Wheat Plant ◽  
Root Systems ◽  
System Size ◽  
Wheat Root ◽  
Field Conditions ◽  
Total N ◽  
Matter Production ◽  
And Control

Spring wheat was inoculated with Azospirillum brasilense Cd or Bacillus C-11-25 under field conditions. Use of a 32P measuring technique showed that the root systems of Azospirillum-inoculated wheat occupied 54% of the soil volumes compared with uninoculated wheat plant root systems. Bacillus-inoculated wheat root systems were 82% of the size of uninoculated wheat root systems. Inoculated and control plants did not differ in dry matter production or in total N content. Inoculated plants received between 5 and 10% of the N contained in their tissues from associative N2 fixation as measured by 15N isotope dilution. Reduction of root system size in inoculated plants explains how the inoculated wheat plants in this study, and in previously reported studies, are able to absorb atmospheric N2 via associative N2 fixation without increasing total plant N uptake.

The Effects of Shading on the Growth and Photosynthetic Capacity of Itchgrass (Rottboellia exaltata)

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 549-553 ◽  
Author(s):  
David T. Patterson
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Photosynthetic Capacity ◽  
High Growth ◽  
High Irradiance ◽  
Gas Analysis ◽  
Dry Matter Production ◽  
Crop Species ◽  
Photosynthetic Rates ◽  
Matter Production

The effects of shade on the growth and photosynthetic capacity of the exotic noxious weed itchgrass (Rottboellia exaltataL. f.) were determined under controlled environment conditions. The plants were grown at day/night temperatures of 29/23 C under 100, 60, 25, and 2% sunlight in a climate-controlled greenhouse. Mathematical growth analysis techniques were used to evaluate the effects of shading on dry matter production and leaf area production. Infrared gas analysis and diffusion porometry techniques were used to evaluate the effects of shading on photosynthesis and stomatal resistance. Shading markedly reduced dry matter production. At 40 days after planting, plants grown in 2, 25, and 60% sunlight had 0.3, 16, and 55%, respectively, of the dry weight of the plants grown at 100% sunlight. Leaf area production was less severely retarded by shading; the plants grown at 2, 25, and 60% sunlight had, respectively, 1.7, 42, and 99% of the leaf area of the plants grown at 100% sunlight. Ambient photosynthetic rates of recently expanded, single, fully exposed leaves were 22.5, 51.6, and 65.5 mg CO2dm-2h-1in the 25, 60, and 100% sunlight treatments, respectively. Photosynthetic rates at saturating irradiance did not differ significantly in plants grown at 25, 60, or 100% sunlight and ranged from 76.4 to 78.0 mg CO2dm-2h-1. Stomatal resistances, ranging from 6.0 to 7.5 s cm-1, also did not differ significantly among these plants. In terms of dry matter production, itchgrass is a shade-intolerant plant. However, even when grown in shade, itchgrass maintains the capacity for high photosynthetic rates and high growth rates when subsequently exposed to high irradiance. These characteristics help explain its competitiveness with crop species.

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