Photosynthetic pigment concentration, organization and interconversions in a pale green Syrian landrace of barley (Hordeum vulgare L., Tadmor) adapted to harsh climatic conditions

Tadmor is a Syrian barley landrace that has adapted to semi-arid environments. Its leaves are pale green because of a 30% decrease in the chlorophyll and the carotenoid content of the chloroplasts (leading to a 7·5% decrease in light absorption) compared with barley genotypes that are not adapted to harsh Mediterranean climatic conditions (e.g. Plaisant). This difference in pigment content was attenuated during growth of the plants in strong light, but was strongly amplified when strong light was combined with a high growth temperature. The low pigment content of Tadmor leaves was not associated with significant changes in the pigment distribution between the photosystems or between the reaction centres of the photosystems and their associated chlorophyll antennae. No significant difference in the photosynthetic activity (O₂ production per unit absorbed light) was observed between Tadmor and Plaisant. The conversion of violaxanthin to zeaxanthin in strong light and its reversal in darkness were much faster and operated at a higher capacity in Tadmor leaves compared with Plaisant leaves, resulting in an increased photostability of photosystem II in the former leaves. The accelerated xanthophylls interconversion in the Syrian landrace was associated with, and possibly related to, an increased fluidity of the thylakoid membranes. The lipid peroxide level was lower in Tadmor compared with Plaisant. In contrast, no difference was found in the non-photochemical quenching of chlorophyll fluorescence between the two barley genotypes. The data indicate that the pale green Syrian landrace is equipped to survive excessive irradiance through a passive reduction of the light absorptance of its leaves, which mitigates the heating effects of strong light, and through the active protection of its photochemical apparatus by a rapid xanthophyll cycling.     

Fairy wrasses perceive and respond to their deep red fluorescent coloration

Fluorescence enables the display of wavelengths that are absent in the natural environment, offering the potential to generate conspicuous colour contrasts. The marine fairy wrasse Cirrhilabrus solorensis displays prominent fluorescence in the deep red range (650–700 nm). This is remarkable because marine fishes are generally assumed to have poor sensitivity in this part of the visual spectrum. Here, we investigated whether C. solorensis males can perceive the fluorescence featured in this species by testing whether the presence or absence of red fluorescence affects male–male interactions under exclusive blue illumination. Given that males respond aggressively towards mirror-image stimuli, we quantified agonistic behaviour against mirrors covered with filters that did or did not absorb long (i.e. red) wavelengths. Males showed significantly fewer agonistic responses when their fluorescent signal was masked, independent of brightness differences. Our results unequivocally show that C. solorensis can see its deep red fluorescent coloration and that this pattern affects male–male interactions. This is the first study to demonstrate that deep red fluorescent body coloration can be perceived and has behavioural significance in a reef fish.     

The Amino Acid Content in Gamma-irradiated Rice†

High phosphate accumulating bacteria were isolated by autoradiography. One isoate, Arthrobacter globiformis PAB-6 accumulated phosphate intracellularly at 20% of dry cell mass in a simple synthetic medium. This amount was 3~7 times higher than type cultures examined. Almost no phosphate was released into the medium after cessation of growth. Fifty percent of total intracellular phosphate was fractionated as nucleic acids, while 20% each was recovered from cold PCA soluble fractions and polyphosphate fractions. The large content of nucleic acids in this bacterium appeared due to increased RNA content, specifically 4 S RNA fraction.     

Inheritance of trunk coloration in the three-spot gourami, Trichogaster trichopterus Pallas

Trunk coloration in Trichogaster trichopterus Pallas is controlled by two autosomal loci acting in a complementary fashion with dominance at both loci required for the expression of the blue sumatranus phenotype.     

EXTERNAL MORPHOLOGY AND PIGMENTATION OF THE VAQUITA, PHOCOENA SINUS (CETACEA: MAMMALIA)

The vaquita, Phocoena sinus , is a porpoise in the family Phocoenidae that lives only in the Gulf of California. The external appearance of P. sinus was unknown until 13 fresh specimens were recently examined. The most obvious morphological feature distinguishing P. sinus from its two congeners is the proportionately higher dorsal fin. The most striking features of the pigmentation pattern are the large black eye patches and the black upper and lower lip patches. In both areas, the pigmentation contrasts sharply with the surrounding light gray coloration. The total lengths of the specimens ranged from 70.3 cm (a neonate) to 143.5 cm (an adult female).     

Algal Carotenoids 51. Secondary carotenoids 2.Haematococcus pluvialis aplanospores as a source of (3S, 3′S)-astaxanthin esters

Aplanospores ofHaematococcus pluvialis MUR 145 contained 0.7% carotenoids (dry wt. basis) consisting of β,β-carotene (5% of total carotenoid), echinenone (4%), canthaxanthin (4%), (3S,3′S)-astaxanthin diester (34%), (3S,3′S)-astaxanthin monoester (46%), (3S,3′S)-astaxanthin (1%) and (3R,3′R,6′R)-lutein (6%). The astaxanthin esters were examined by TLC and HPLC and VIS,¹H NMR and mass spectra recorded. Their chirality was determined by the camphanate method (Vecchi & Müller, 1979) after anaerobic hydrolysis. The tough cell wall of the aplanospores required enzymatic treatment prior to pigment extraction. The potential use of this microalga as a feed ingredient in aquaculture is discussed briefly.     

甘蔗伤流液中保绿活性物质的分离与初步鉴定

通过化学与物理学方法,从甘蔗(Sugar-cane)伤流液中分离出五种活性因素,对离体叶片有不同程度的保绿效应。依其化学性质判断,应属嘌呤化合物,可能是细胞分裂素物质。     

Species- and age-dependent sensitivity to ozone in young plants of pea,wheat and spinach: Effects on acyl lipid and pigment content and metabolism

Acyl lipids and pigments were analyzed in young plants of garden pea, spring wheat and spinach exposed to < 5 or 65 nl l^?1 ozone 12 h per day for 6 days. In one set of experiments, the plants were exposed to ¹⁴CO₂ for 2 h 3 days prior to ozone exposure. The plants responded differently to the moderately enhanced level of ozone used Spinach was not at all sensitive while in both pea and wheat, leaves of different ages differed in ozone sensitivity. In pea, ozone sensitivity increased with leaf age. In the second and third oldest leaves, the amounts of galactolipids per leaf area and the proportions of 18:3 of the total lipid extract and of phosphatidylglycerol decreased. In the second oldest leaf, ozone also caused a decreased proportion of 18:3 of monogalactosyldiacylglycerol. In the fourth oldest leaf, lipid composition and galactolipid unsaturation was unaffected, but ozone caused decreased leaf expansion resulting in increased acyl lipid content per leaf area. In both the first and second leaves of wheat, ozone fumigation caused a marked decrease in the content of monogalactosyldiacylglycerol and in the first leaf, the contents of phosphatidylcholine and phosphatidylethanolamine increased. The proportion of 18:3 in phosphatidylcholine was larger in ozone-fumigated than in control plants, while the reverse applied for phosphatidylglycerol. In the oldest sampled leaves of pea and wheat, ozone caused an increase in the radioactivity associated with β-carotene, indicating increased turnover. Thus, while spinach was unaffected, in both pea and wheat ozone caused a decrease in the proportion of chloroplast membrane lipids to non-chloroplast membrane lipids in older leaves while younger leaves were less sensitive.     

Photoprotective effect of kinetin on pigment content and photochemical activities of wheat chloroplasts agingin vitro

The effects of kinetin (Kn) on pigment content and electron transport activities (ETA) in wheat leavesin vivo and chloroplastsin vitro aging in light was investigated. Excised wheat leaves were infiltrated with Kn for 3 h under irradiation. The treatment increased zeaxanthin (Zx) content by 40% and also increased chlorophyll (Chia, Chib) and major carotenoid (Car) contents in the leaves (per fresh mass unit). Chloroplasts isolated from Kn treated leaves, when incubated in light for 4 h showed relatively lower pigment loss and slower loss of ETA compared to the chloroplasts of untreated leaves. These observations suggest photoprotective action of Kn. The photoprotection was more prominent when Kn was applied directly to the irradiated chloroplastsin vitro. Moreover, chloroplasts agingin vitro under irradiation without Kn treatment lost pigments and ETA. Within 3 h of irradiation, both whole chain (H₂O to methylviologen) electron transport as well as photosystem (PS) 2 activity were completely lost. However, in the chloroplasts treated with Kn, the loss of pigments was slow and even after 4 h of irradiation the chloroplasts retained 15 % of PS 2 and 9 % of whole chain ETA. In the untreated chloroplasts, the loss of Zx after 4 h of irradiation was 49 % whereas in Kn treated samples its level was 1.3 times higher than that of control. Since a higher level of Zx was maintained in Kn treated chloroplasts, photoprotective action of Kn is possibly mediated through Zx. One of us (NKC) thanks Sambalpur University for study leave and Department of Biological Sciences, Mankato State University, Mankato for labortory facilities.