Quantum-size semiconductor microcrystallites of ZnCdS and CdS in aqueous and isopropanol solution were optically excited using intense sub-picosecond UV laser pump pulses. Broad-band optical probing monitored the yield of electron emission and the build-up of primary photochemical products. With typical pump fluences of femtosecond light pulses multiple photons are absorbed by one quantum-dot l...

Rhododendron chrysanthum Pall., live in Changbai Mountain being exposed to chilling temperature, high light intensities and water scarcity condition. To adapt to the harsh environment, the cold resistance mechanisms of R. chrysanthum have been successfully evolved in the long-term adaptive process. In our present work, the methods of proteomics combined with physiological and biochemical analys...

Interspecific differences in the response of microalgae to stress have numerous ecological implications. However, little is known of intraspecific sensitivities and the potential role of local genetic adaptation of populations. We compared the allelochemical sensitivity of 23 Pediastrum duplex Meyen strains, a common component of the freshwater phytoplankton. In order to test for local genetic ...

Under conditions (0.2% CO2; 1% O2) that allow high rates of photosynthesis, chlorophyll fluorescence was measured simultaneously with carbon assimilation at various light intensities in spinach (Spinacia oleracea) leaves. Using a stoichiometry of 3 ATP/CO2 and the known relationship between ATP synthesis rate and driving force (Delta pH), we calculated the light-dependent pH gradient (Delta pH)...

Photosynthetic bacteria contain bacteriochlorophyll (BChl) that absorbs light and delivers the resulting singlet excitation energy to photochemical reaction centers.' The reaction centers, which have been isolated in a form free of lightharvesting BChl,'-3 contain a photochemically specialized BChl which in Rhodopseudomonas spheroides is called P870 after its absorption maximum near 870 nm. Exc...

In some studies, tissues from plants that have been genetically transformed to overproduce antioxidant enzymes sustain less damage when abruptly exposed to short-term chilling in the laboratory. However, few studies have examined the performance of transgenic plants during longer-term growth under chilling conditions. We compared growth of transgenic cotton that overproduces glutathione reducta...

sesame could be an appropriate oilseed crop for water limited environments. this research was aimed at studying growth, leaf chlorophyll fluorescence, proline content, yield and yield components of sesame cultivars under different moisture regimes. a 4-replicate split plot rcbd field experiment was conducted at the lavark research farm, college of agriculture, isfahan university of technology, ...

Increasing the leaf temperature of intact cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) plants caused a progressive decline in the light-saturated CO2-exchange rate (CER). CER was more sensitive to increased leaf temperature in wheat than in cotton, and both species demonstrated photosynthetic acclimation when leaf temperature was increased gradually. Inhibition of CER was not...

Hydrologic alterations of river systems in western North America over the past century have increased soil salinity, contributing to the establishment and spread of an introduced halophytic species, Tamarix ramosissima (Ledeb.). The physiological responses of Tamarix ramosissima to salinity stress are incompletely known. To assess the salinity tolerance of this species, we measured several whol...

Melatonin has been confirmed to relieve drought stress in various plant species. However, the mechanism garden chrysanthemums remains be elucidated. Here, we examined putative role of exogenous melatonin application improving drought-stress tolerance Chrysanthemum seedlings. Treatment with (100 µM) significantly mitigated negative effects on seedling photosynthetic parameters and physiological ...