Author: engeladmin

Author: Lichtenthaler, H.K. Description: The current concept of stress in plants has been well developed over the past 60 years. Any unfavorable condition or substance that affects or blocks a plant’s metabolism, growth, or development is regarded as stress. Vegetation stress can be induced by various natural and anthropogenic stress factors. One has to differentiate between short-term and long-term stress effects as well as between low-stress events that can be partially compensated for by acclimation, adaptation, and repair mechanisms, on the one hand, and strong stress or chronic stress events…

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: Callaway, R.M.; Brooker, R.W.; Choler, P.; Kikvidze, Z.; Lortie, C.J.; Michalet, R.; Paolini, L.; Pugnaire, F.I.; Newingham, B.; Aschehoug, E.T.; Armas, C.; Kikodze, D.; Cook, B.J. Description: Plants can have positive effects on each other. For example, the accumulation of nutrients, provision of shade, amelioration of disturbance, or protection from herbivores by some species can enhance the performance of neighbouring species. Thus the notion that the distributions and abundances of plant species are independent of other species may be inadequate as a theoretical underpinning for understanding species coexistence and…

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…

Author: Agnew, M.L.; Carrow, R.N. Description: In this greenhouse study, we investigated the effects of soil compaction and moisture stress preconditioning on stomatal diffusive resistance (Rs), leaf water potential (Y1), and canopy minus air temperatures of Kentucky bluegrass (Poa pratensis L. ‘Ram I’). The compaction treatments were: (i) NC = no compaction, (ii) LT = long-term compaction over a 99-day period, and (iii) ST = short-term compaction for 9 days. The compactive treatment was equivalent to 720 J energy. Irrigation regimes were initiated at the same time as LT compaction…

Author: Zhang, S.; Wang, X. Description: Basal thermotolerance is very important for plant growth and development when plants are subjected to heat stress. However, little is known about the functional mechanism of gibberellins (GAs) in the basal thermotolerance of plants. In the present work, we provide molecular evidence that a member of the gene family encoding the GA-stimulated Arabidopsis (GASA) peptides, namely GASA5, is involved in the regulation of seedling thermotolerance. The GASA5-overexpressing plants displayed a weak thermotolerance, with a faster cotyledon-yellowing rate, lower seedling-survival rate, and slower hypocotyl elongation,…

Author: Ruiz Carrasco, K.B.; Baroni Fornasiero, R.; Tassoni, A.; Bagni, N. Description: This study describes two phenotypes of Arabidopsis thaliana (ecotype Columbia) developed in vitro under salt stress (75 mM NaCl). The phenotypes 01 and 02 appeared visibly distinguishable by rosette morphology and competence to produce flowers. Phenotype 01, sensible to salt stress, accumulated high quantities of Na+, showed a slight reduction in dry mass, and high protein and chlorophyll contents. Moreover, its anatomy exhibited some xeromorphic traits. Phenotype 02, clearly salt tolerant, showed a morphology similar to control plants,…

Author: Oraby, H.; Ahmad, R. Description: Salinity is a major abiotic constraint affecting oat productivity. Several physiological and biochemical traits have been found to be related to yield maintenance under salinity. The impact of introducing the Arabidopsis CBF3 gene controlled by the rd29A stress-inducible promoter in T(2) transgenic oat on salinity tolerance and associated physiological changes were studied. Compared with the non-transgenic control, transgenic T(2) plants exhibited greater growth and showed significant maintenance of leaf area, relative water content, chlorophyll content, photosynthetic and transpiration rates as well as increased levels…