Search Results

You are looking at 71 - 80 of 2,019 items for :

  • photosynthesis x
  • Refine by Access: All x
Clear All
Free access

J.W. Moon Jr., D.M. Kopec, E. Fallahi, C.F. Macino, D.C. Slack, and K. Jordan

Photosynthesis was reduced by 85% to 90% in perennial ryegrass (Lolium perenne L. cv. Derby) following a one-day chilling exposure at 8C day (450 μmol·s-1·m-2 PPF) and 5C night. Seven days of recovery at 22/17C day/night were required for full recovery of photosynthesis. More than 75% of the limitation in photosynthesis following chilling was due to non-stomatal factors, and reduced initial slopes of CO2 assimilation vs. intercellular CO, indicate that photosynthetic capacity was reduced for 5 days following chilling. Carbon dioxide assimilation at saturating intercellular CO2 (>500 μmol·mol-l) was also reduced by chilling, indicating again that stomatal limitations were a minor contributor to the photosynthetic reduction observed under ambient CO2.

Open access

Mokhles A. Elsysy, Andrew Hubbard, and Todd C. Einhorn

calculates photosynthesis rate (i.e., flux, µmol·m −2 ·s −1 ) from direct measures (via two IRGAs) of the CO 2 concentration entering and exiting the leaf cuvette, relative to the leaf area in the cuvette (4.5 cm 2 ). CO 2 concentration was controlled (390

Free access

Vania Lanari, Oriana Silvestroni, Alberto Palliotti, Alan Green, and Paolo Sabbatini

Not much is known about the influence of leaf position on photosynthesis in water-stressed leaves. We do know that stomatal control of water loss is an early plant response to water deficit under field conditions ( Chaves, 1991 ; Cornic and

Free access

Marc W. van Iersel and Bruce Bugbee

Dibutylurea (DBU), a breakdown product of benomyl, may be partially responsible for the previously reported phytotoxicity of the fungicide Benlate DF. We quantified the effect of DBU on the growth of two popular bedding plant species, petunia (Petunia × hybrida) and impatiens (Impatiens wallerana Hook. f.). DBU reduced photosynthesis of both species, and its effect strongly depended on the amount of DBU applied. The effects of DBU were most apparent 2 to 4 days after treatment, at which time 1.20 g·m-2 (corresponding to 10% DBU in Benlate DF at maximum labeled drench rate) inhibited photosynthesis completely. DBU also decreased flower number and caused marginal necrosis. DBU effects were more pronounced in low relative humidity. Benlate DF containing 3.1% DBU and an equivalent amount of reagent grade DBU had similar effects on photosynthesis and petunia necrosis. Our results showed that DBU is responsible for at least part of the phytotoxic symptoms that can be caused by Benlate DF. However, other ingredients or breakdown products may also contribute to the phytotoxic symptoms of Benlate DF.

Free access

Christopher J. Currey and Roberto G. Lopez

of cuttings declines after severance ( Veierskov, 1988 ). Although photosynthesis and carbohydrate production and storage are influenced by several biotic and abiotic factors such as carbon dioxide, temperature, nutrition, and water status, light is a

Free access

Dalong Zhang, Yuping Liu, Yang Li, Lijie Qin, Jun Li, and Fei Xu

therefore effectively enhance plant photosynthesis and growth ( Lu et al., 2015 ; Zhang et al., 2015 , 2017 , 2018 ). It is generally considered that the movement of water through the soil–plant–atmosphere continuum is driven by a gradient in water

Open access

Haijie Dou, Genhua Niu, Mengmeng Gu, and Joseph Masabni

photosynthesis in lower plant canopy levels and subsequently increase plant yield at the whole plant canopy level ( Dou et al., 2019a ; Terashima et al., 2009 ; Wang and Folta, 2013 ). In addition, G wavelengths induce shade avoidance responses in plants, such

Free access

Ajmer S. Bhagsari and Doyle A. Ashley

Field experiments with 15 sweet potato [Ipomoea batatas L. (Lam.)] genotypes were conducted to study the physiological basis of yield in 1981 and 1982. The leaf area index differed significantly among the sweet potato genotypes during early and late phases of growth, hut showed an inconsistent relationship with yield. Single leaf net photosynthesis ranged from 0.74 to 1.12 mg CO2/m' per sec. Canopy photosynthesis for sweet potato genotypes differed significantly in 1981, but not in 1982. It ranged from 0.81 to 1.16 mg CO2/m2 per sec in Aug. 1981. and from 0.63 to 0.88 mg CO2/m2 per sec in 1982. Four hours after “C-labeling, 14C-assimilate translocation from the treated leaf ranged from 21% to 46%, but did not differ significantly among the genotypes. At final harvest, harvest index [HI, defined as (storage root yield/total biological yield) × 100] of the genotypes varied from 43% to 77% and 31% to 75% for 1981 and 1982, respectively. Canopy photosynthesis during September was significantly correlated with storage root dry matter yield (r = 0.54*) in 1981 and with phytomass (above-ground biomass plus storage roots) (r = 0.60*) in 1982. Both phytomass and HI were significantly correlated with storage root matter yield. Canopy photosynthetic evaluation of sweet potato germplasm may be-more relevant when the storage root sinks are at an advanced stage of development. Our study suggests that yield is poorly predicted by Pn, particularly when the genotypes have different leaf sizes.

Open access

Hong Jiang, Zhiyuan Li, Xiumei Jiang, and Yong Qin

the photosynthetic characteristics, antioxidant system, and osmotic regulation of multiple vegetative organs of various crops have been studied. Salt stress can inhibit photosynthesis in plants (Han et al., 2014). High salt stress can reduce g S

Free access

Rebecca M. Harbut, J. Alan Sullivan, John T.A. Proctor, and Harry J. Swartz

photosynthesis ( Zelitch, 1982 ). The increases in yield over the last century have been largely the result of increases in harvest index and light interception; however, the role that photosynthesis has played is not completely understood ( Richards, 2000 ). In