The effects of enhanced ozone and enhanced carbon dioxide concentrations on biomass, pigments and antioxidative enzymes in spruce needles (Picea abies L.)

During one growing period, 5-year-old spruce trees (Picea abies L., Karst.) were exposed in environmental chambers to elevated concentrations of carbon dioxide (750 cm³ m^?3) and ozone (008 cm³ m^?3) as single variables or in combination. Control concentrations of the gases were 350cm³ m^?3CO₂ and 0.02 cm³ m ^?3 ozone. To investigate whether an elevated CO₂ concentration can prevent adverse ozone effects by reducing oxidative stress, the activities of the protective enzymes superoxide dismutase, catalase and peroxidase were determined. Furthermore, shoot biomass, pigment and protein contents of two needle age classes were investigated. Ozone caused pigment reduction and visible injury in the previous year's needles and growth reduction in the current year's shoots. In the presence of elevated concentrations of ozone and CO₂, growth reduction in the current year's shoots was prevented, but emergence of visible damage in the previous year's needles was only delayed and pigment reduction was still found. Elevated concentrations of ozone or CO₂ as single variables caused a significant reduction in the activities of superoxide dismutase and catalase in the current year's needles. Minimum activities of superoxide dismutase and catalase and decreased peroxidase activities were found in both needle age classes from spruce trees grown at enhanced concentrations of both CO₂ and ozone. These results suggest a reduced tolerance to oxidative stress in spruce trees under conditions of elevated concentrations of both CO₂ and ozone.     

A new genus and two new species of aphids (Homoptera: Aphididae) from north-west India

A new aphid genus Raychaudhuriella and two new specices viz. Raychaudhuriella myzaphoides and Rhopalosiphoninus sensoriatus are described from Himachal Pradesh, north-west Himalaya. The affinity of Raychaudhuriella gen. nov. is drawn with Aspidophorodon Verma, Cavariela del Guercio, Myazphis van der Goot, Tricaudatus Narzikulov and Vesiculaphis del Guercio. Figures and biometrical data of the new species have been provided.     

Protein and Ribonucleic Acid Synthesis by Plant Mitochondrial Systems

The incorporation of ¹⁴C-labelled phenylalanine into proteins of the mitochondrial systems obtained from 48-h germinating seeds of Vigna sinensis (L.) Savi can be stimulated by polyuridylic acid [poly (U)] and depressed by rifampicin, which is, however, ineffective if poly (U) is allowed to interact with the incorporating system before the antibiotic has access to it. A system consisting of a mitochondrial S-100 fraction and ribosomes from the same source with other cofactors can bring about polymerization of phenylalanine. The incorporation of ¹⁴C-labelled uracil into RNA by the plant mitochondria is greatly dependent on the exogenous addition of adenine, guanine, cytosine and also on 5-phosphoribosyl-l-pyrophosphate (5-PRPP). It is greatly suppressed by rifampicin and ethidium bromide.     

Hitherto unknown alate morphs of two species of Eumyzus Shinji (Homoptera: Aphididae) from India with a key to alate viviparous females

The hitherto unknown alate viviparous females of Eumyzus pruni Chakrabarti & Bhattacharya and Eumyzus hydrangi Chakrabarti & Bhattacharya from the Garhwal and Kumaon regions of northwest Himalaya are described and illustrated. A key is provided to all of the known alate viviparous females of Eumyzus species known from throughout the world.     

Key to Indian species of Periphyllus including four new species and hitherto unknown morphs from North-west Himalaya (Homoptera: Aphididae)

ABSTRACT. Four new species of Periphyllus; P.aceriphaga Chakrabarti & Mandal, P.caesium Chakrabarti & Saha, P.garhwalensis Chakrabarti & Mandal and P.pallidus Chakrabarti & Saha are described. Hitherto unknown apterous viviparous female of P.villosii Chakrabarti and four dimorphs are also recorded. Keys to distinguish the species of apterous viviparous females, alate viviparous females, alate males and dimorphs are provided.