The organization and function of the photochemical apparatus of Synechococcus 6301 was investigated in cells grown under yellow and red light regimes. Broadband yellow illumination is absorbed preferentially by the phycobilisome (PBS) whereas red light is absorbed primarily by the chlorophyll (Chl) pigment beds. Since PBSs are associated exclusively with photosystem II (PSII) and most of the Ch...

A wheat stay-green mutant, tasg1, was previously generated via mutation breeding of HS2, a common wheat cultivar (Triticum aestivum L.). Compared with wild-type (WT) plants, tasg1 exhibited delayed senescence indicated by the slower degradation of chlorophyll. In this study, the stability of proteins in thylakoid membranes was evaluated in tasg1 under drought stress compared with WT plants in t...

Sea-ice algae play a crucial role in the ecology and biogeochemistry of sea-ice zones. They not only comprise base ecosystems, but also seed populations extensive ice-edge blooms during ice melt. Ice must rapidly acclimate to dynamic light environments, from low under sea high within open waters. Recently, iron (Fe) deficiency has been reported for diatoms eastern Antarctic pack ice. Low Fe ava...

Abstract Photosynthesis with highly photoreactive chlorophyll (Chl) provides energy for plant growth but simultaneous risk of photooxidative damage and photoprotection costs. Although the leafless orchid Cymbidium macrorhizon mostly depends on mycorrhizal fungi carbon, it accumulates Chl particularly during fruiting may not be fully mycoheterotrophic. In fact, stable isotopic analysis suggested...

Iron availability strongly governs the growth of Southern Ocean phytoplankton. To investigate how iron limitation affects photosynthesis as well as the uptake of carbon and iron in the Antarctic diatom Chaetocerossimplex, a combination of chlorophyll a fluorescence measurements and radiotracer incubations in the presence and absence of chemical inhibitors was conducted. Iron limitation in C. si...

Photosynthetic organisms are able to sense energy imbalances brought about by the overexcitation of photosystem II (PSII) through the redox state of the photosynthetic electron transport chain, estimated as the chlorophyll fluorescence parameter 1-qL, also known as PSII excitation pressure. Plants employ a wide array of photoprotective processes that modulate photosynthesis to correct these ene...

'Cleopatra' tangerine (Citrus reshni Hort. ex Tanaka) seedlings were irrigated daily for 8 weeks with 1/4 strength Hoagland's nutrient solution containing 0 (control) or 2 mM aluminum (Al). Leaves from Al-treated plants had decreased CO2 assimilation and stomatal conductance, but increased intercellular CO2 concentrations compared with control leaves. On a leaf area basis, 2 mM Al increased act...

The study evaluated basil plants’ response (var. Sweet Green) to increased concentrations of sodium chloride (NaCl) and macro- micronutrients in the medium. following variants were used: ½ Hoagland nutrient solution containing NaCl (0, 80 160 mM) 4/2 with 0 mM NaCl. Biometric physiological parameters measured 20 days after saline application. application caused suppression growth. height plants...

xxxviiiABSTRACT Global climate change is leading to the rise of ocean temperatures and is triggering masscoral bleaching events on reefs around the world. This involves the expulsion of thesymbiotic dinoflagellate algae, known as zooxanthellae, from the coral host. Coralbleaching is believed to occur as a result of damage to the photosynthetic apparatus ofthese symbionts...