Search Results for: plants stress

Author: Pearcy, R.W.; Tumosa, N.; Williams, K. Description: The relationships of photosynthetic characteristics to the competitive interactions of a C3 plant, Chenopodium album, and a C4 plant, Amaranthis retroflexus, were investigated in different temperature and water supply regimes. Both species had similar photosynthetic rates at 25 degrees C, but at higher temperatures, Amaranthus had substantially greater rates than Chenopodium. Conversely, at lower temperatures, Chenopodium had an advantage. The competitive abilities in mixtures exhibited a close parallel to the photosynthetic performances with Amaranthus having an advantage at high temperatures and Chenopodium…

Author: Ashraf, M.; Habib-ur-Rehman, Description: The interactive effect of additional amount of NO3-N and long-term waterlogging on maize was studied in glasshouse conditions. Forty-two-day-old plants were subjected to continuous flooding for 21 days at three different NO3-N regimes (196, 294 and 392 mg N kg-1 soil). Shoot fresh mass and leaf area of waterlogged plants reduced significantly at two higher NO3 regimes. Leaf water potential was generally decreased, whereas osmotic potential increased in all waterlogged plants but much reduction in leaf water potential was found at the highest external NO3…

Author: Wand, S.J.E.; Midgley, G.Y.F.; Jones, M.H.; Curtis, P.S. Description: C4 plants contribute approximately 20% of global gross primary productivity, and uncertainties regarding their responses to rising atmospheric CO2 concentrations may limit predictions of future global change impacts on C4-dominated ecosystems. These uncertainties have not yet been considered rigorously due to expectations of C4 low responsiveness based on photosynthetic theory and early experiments. We carried out a literature review (1980-97) and meta-analysis in order to identify emerging patterns of C4 grass responses to elevated CO2, as compared with those of…

Author: Schauberger, B.; Archontoulis, S.; Arneth, A.; Balkovic, J.; Ciais, P.; Deryng, D.; Elliott, J.; Folberth, C.; Khabarov, N.; Muller, C.; Pugh, T.A.M.; Rolinski, S.; Schaphoff, S.; Schmid, E.; Wang, X.; Schlenker, W.; Frieler, K. Description: High temperatures are detrimental to crop yields and could lead to global warming-driven reductions in agricultural productivity. To assess future threats, the majority of studies used process-based crop models, but their ability to represent effects of high temperature has been questioned. Here we show that an ensemble of nine crop models reproduces the observed…

Author: Rodrigues, M.L.; Pacheco, C.M.A.; Chaves, M.M. Description: Lupinus albus L. from different climatic origins responded to a 15 d period of water shortage during flowering by losing 50% of the total leaf canopy and gaining 55% in stem dry weight. Water deficits also led to a significant increase in the fine root length density and a slight increase in the fine root dry weight. The latter increase was especially pronounced in the deeper soil layers. Some marginal differences among genotypes were observed in the responses. Stomatal closure by midday…

Author: Prasad, P.V.V.; Pisipati, S.R.; Ristic, Z.; Bukovnik, U.; Fritz, A.K. Description: Climate models predict greater increases in nighttime temperature in the future. The impacts of high nighttime temperature on wheat (Triticum aestivum L.) are not well understood. Objectives of this research were to quantify the impact of high nighttime temperatures during reproductive development on phenology, physiological, vegetative, and yield traits of wheat. Two spring wheat cultivars (Pavon-76 and Seri-82) were grown at optimum temperatures (day/night, 24/14°C; 16/8 h light/dark photoperiod) from sowing to booting. Thereafter, plants were exposed to…

Author: Hawksworth, D.L. Description: Fungi, members of the kingdoms Chromista, Fungi s.str. and Protozoa studied by mycologists, have received scant consideration in discussions on biodiversity. The number of known species is about 69 000, but that in the world is conservatively estimated at 1·5 million; six-times higher than hitherto suggested. The new world estimate is primarily based on vascular plant: fungus ratios in different regions. It is considered conservative as: (1) it is based on the lower estimates of world vascular plants; (2) no separate provision is made for the…

Author: Ghimire, S.R.; Charlton, N.D.; Bell, J.D.; Krishnamurthy, Y.L.; Craven, K.D. Description: This study was conducted to explore fungal endophyte communities inhabiting native switchgrass plants from the tallgrass prairie of northern Oklahoma. The primary focus was to isolate these endophytes in pure culture from surface-sterilized plant tissues and provide taxonomic identifications based on comparative analysis of ITS rDNA gene sequences. From these data, we evaluated the biodiversity of these potentially beneficial endosymbionts from this rapidly disappearing habitat of the Great Plains. While important from a strictly conservationist standpoint, this survey…

Author: DeRidder, B.P.; Crafts-Brandner, S.J. Description: Early season development of cotton is often impaired by sudden episodes of chilling temperature. We determined the chilling response specific to postemergent 13-day-old cotton (Gossypium hirsutum L. cv. Coker 100A-glandless) seedlings. Seedlings were gradually chilled during the dark period and rewarmed during the night-to-day transition. For some chilled plants, the soil temperature was maintained at control level. Plant growth, water relations and net photosynthesis (P(n)) were analyzed after one or three chilling cycles and after 3 days of recovery. Three chilling cycles led to…

Author: Bajji, M.; Kinet, J.-M.; Lutts, S. Description: Salt stress effects on growth, osmotic adjustment, mineral and organic contents and soluble peroxidase activities were determined in roots and leaves of Atriplex halimus and their corresponding callus cultures. Low NaCl doses (150 mM) promoted shoot growth, corroborating the halophilic nature of this species; in these stress conditions, Na+ concentration markedly increased in the leaves indicating that salinity resistance was not associated with the ability of the plants to restrict sodium accumulation in the aerial part. Whole organs and their corresponding calli…