This study evaluates, for the first time, the influence of biofilms on single and double optical window (SOW and DOW, respectively) fast repetition rate fluorometer (FRRF) measurements of microalgal photosystem-II initial fluorescence (F0), maximum fluorescence (Fm), variable fluorescence (Fv = Fm - F0), quantum yield (Fv/Fm) and functional absorption cross section (σPSII)]. Biofilms with chlor...

A chlorophyll f containing cyanobacterium, Halomicronema hongdechloris (H. hongdechloris) was isolated from a stromatolite cyanobacterial community. The extremely slow growth rate of H. hongdechloris has hindered research on this newly isolated cyanobacterium and the investigation of chlorophyll f-photosynthesis. Therefore, optimizing H. hongdechloris culture conditions has become an essential ...

introduction safflower (carthamus tinctorius l.) is an important oilseed crop grown throughout the semiarid regions in many parts of the world. it has been cultivated for its oil and flowers and as a meal. alkaline stress is caused by alkaline salts such as na2co3 or nahco3 in the soil. alkaline stress, is widespread environmental constraint affecting crop productivity ,which can inhibit absorp...

Leaves of rye seedlings (Secale cereale L.) grown in the presence of four chlorosis-inducing herbicides under a low light intensity of 10 lux formed chlorophyll. When segments of such dim-light-grown leaves were exposed to 30,000 lux at either 0 degrees C or 30 degrees C, treatments with aminotriazole or haloxidine (group 1) showed no or only minor changes of their chlorophyll contents. In trea...

iron deficiency in soil reduces the quality of durum wheat leading to fe deficiency in human. thus, this experiment investigated the effects of foliar application of nano-iron oxide (2 and 4 g l-1), iron chelate (edta), (4 and 8 g l-1), iron sulfate (4 and 8 g l-1), and the control on grain yield and quality, yield components, chlorophyll and carotenoids contents, peroxidase (pox), catalase (ca...

Response of tea plants to B deficiency was studied in hydroponic medium under environmentally controlled conditions. Plants height, number of leaves and dry matter production of shoot and root were significantly decreased by B deficiency. Concentration of chlorophyll, carotenoids, anthocyanins and flavonoids was not affected by B deficiency in the young leaf, while a significant reduction of Ch...

A mass spectrometric method combining (16)O/(18)O and (12)C/(13)C isotopes was used to quantify the unidirectional fluxes of O(2) and CO(2) during a dark to light transition for guard cell protoplasts and mesophyll cell protoplasts of Commelina communis L. In darkness, O(2) uptake and CO(2) evolution were similar on a protein basis. Under light, guard cell protoplasts evolved O(2) (61 micromole...

The in vivo biosynthesis of the P700 chlorophyll a-apoprotein was examined to determine whether this process is light regulated and to determine its relationship to chlorophyll accumulation during light-induced chloroplast development in barley (Hordeum vulgare L.). Rabbit antibodies to the 58,000-62,000-mol-wt apoprotein were used to measure relative synthesis rates by immunoprecipitation of i...