Introduction Leaf senescence involves degradation of proteins, The activities of chlorophyllase, contents of pigments chlorophylls, nucleic acids, membranes, and subsequent including chlorophyll a and b, chlorophyllide a and b, transport of some of the degradation products to other and phaeophorbide a during leaf senescence under parts of the plant (Buchanan-Wollaston, 1997; Noodén, low oxygen ...

The effects of UV-B radiation on the amount of chlorophyll a, b, carotenoids, flavonoids, anthocyanins, and polyphenols of three soybean cultivars was studied. After germination in the incubator, plants were put in pots of soil and during 3 weeks and irrigated with Hoagland solution every day. After 3 weeks, plants were exposed to UV-B for 20 min every day for a week. In each cultivar, UV-B red...

In order to study the effects of humic acid foliar spraying on morphological traits, photosynthetic pigmentation, and essential oil content of Dracocephalum moldavica, a factorial experiment was conducted based on a randomized complete block design with three replications in Saveh. The investigated factors included the use of humic acid at four levels 0 (control), 200, 400, and 800 mg/L and eth...

Higher plants acclimate to various light environments by changing the antenna size of a light-harvesting photosystem. The antenna size of a photosystem is partly determined by the amount of chlorophyll b in the light-harvesting complexes. Chlorophyllide a oxygenase (CAO) converts chlorophyll a to chlorophyll b in a two-step oxygenation reaction. In our previous study, we demonstrated that the c...

Algal pigment composition is an indicator of phytoplankton community structure that can be estimated from optical observations. Assessing the potential capability to retrieve different types pigments absorption critical for further applications. This study investigated performance three models and utility hyperspectral in vivo spectra retrieving using a large database (n = 1392). Models based o...

Chlorophyll b is synthesized from chlorophyll a and is found in the light-harvesting complexes of prochlorophytes, green algae, and both nonvascular and vascular plants. We have used conserved motifs from the chlorophyll a oxygenase (CAO) gene from Chlamydomonas reinhardtii to isolate a homologue from Arabidopsis thaliana. This gene, AtCAO, is mutated in both leaky and null chlorina1 alleles, a...

Chlorophyll-deficient individuals have been reported in most species of plants studied intensively by genetic methods. The majority of these chlorotic types have been shown to be the expression of a single gene mutation. However, there is a large group of types that exhibit maternal inheritance, and transmission of the deficiency to their offspring is conditioned by the cytoplasm. Until rather ...

Field studies were conducted to determine the potential for alterations in physiology and the intraspecific variation in sensitivity of 20 wheat (Triticum aestivum) cultivars to enhanced ultraviolet-B (UV-B, 280-315 nm) radiation. The supplemental UV-B radiation was 5 kJ m(-2), simulating a depletion of 20% stratospheric ozone. Out of 20 wheat cultivars (from South China, North China and Mexico...