V. S. Verma

Study on the Effect of Flavonoids on the Inf ectivity of Potato Virus X

Summary In the present study the mechanism of 3 flavonoids, viz. morin, quercetin, and rutin, on the multiplication and the infectivity of a plant virus, viz. potato virus X, was investigated. It is concluded that the inhibition of viral particles by the tested flavonoids is only by their direct contact in vitro, while in vivo they do not inactivate the virus significantly. Strong inhibition of the virus, when applied to the Local lesion of the host long before inoculation, may be due to the fact that these flavonoids inhibit the infectivity of potato virus X by altering the susceptibility of the host plant, and they probably do so by blocking the infective sites on the leaf surface.

Influence of pigweed mosaic virus on free amino acids of pigweed (Amaranthus viridis L.)

An increase in the number of amino acids inAmaranthus viridis plants infected with pigweed mosaic virus was found.

Trianthema portulacastrum — Local lesion host for brinjal mosaic and tobacco mosaic viruses

Summary This paper deals with the first record of virus infections (brinjal mosaic virus and tobacco mosaic virus) on Trianthema portulacastrum L., a common weed in India. Trianthema portulacastrwn L., locally known as “Bishkhapra”, is a common weed with medicinal properties, and grows extensively in summer everywhere. It is a succulent, prostrate, glabrous or slightly pubescent herb with many branched, angular stems, leaves broader towards the tip, fruits small like flowers, concealed in the base of the leaf stalk. Experiments were carried out to determine the utility of T. portulacastrum as a local lesion host. The culture of mosaic disease of brinjal (Seth et al. 1967) and SK strain of tobacco mosaic virus (Verma et al. 1972) were maintained on Nicotiana glutinosa L. and N. tabacum cv. White Burley, respectively. The test plants of T. portulacastrum were raised in 4 inch pots, filled with sterilized soil, and kept inside the insect-proof glasshouse. For inoculations, the conventional method of macerating the infected leaf material in a mortar and pestle and rubbing the test seedlings by means of a cotton wool swab was employed. The plants were maintained on glasshouse benches at a temperature of 29 to 30°C. Within 6”7 days of inoculation, distinct countable chlorotic local lesions appeared which turned necrotic with a yellow halo over a period of 10”12 days. The lesions produced by both these viruses on T. portulacastrum were slightly different in their size and necrotic reaction on this host. Leaves of T. portulacastrum developed at first a few local lesions, followed by mosaic mottling of the newly emerging leaves in case of brinjal mosaic virus. Systemic infection, however, does not occur by tobacco mosaic virus in this host. A perusal of literature suggested that this constitutes the only record of a virus infection on Φ in India and is the first record as a local lesion host for brinjal mosaic virus and tobacco mosaic virus SK strain. Kristensen (1955) reported T. portulacastrum a systemic host of Beet yellows virus from Denmark.

Vinca phyllody — A mycoplasmal disease in India

Summary Mycoplasma-like bodies have been found in the phloem elements of Vinca plants infected with phyllody disease, transmissible by grafting. Such structures are lacking in phloem elements of normal plants. No virus particles, fungi, or bacteria were associated with this disease. This report constitutes the first record of a phyllody disease on Vinca rosea in India and is different in size from those reported from other countries.

Effect on protein content by viral infections in seeds of wheat, bajra, and urid

Summary Increased percentage of protein in diseased wheat and bajra seeds was observed compared to healthy ones while in the protein content of diseased and healthy urid seeds there was no difference at all. This increase in percentage of protein content may be due to faster rate of metabolism in diseased ones but in case of urid the reason is not known.

A Mosaic Disease of Bamboo

Summary Bambusa arundinacea was observed to be affected with a mosaic disease in India. It has flexuous long thread-like particles (490 - 520 nm) and belongs to the Potex virus group. This is the first report of a virus disease on B. arundinacea in India.

Phytotoxins — A study of specificity in India

Summary Phytotoxins of microbial origin determined in India have been described. None of them was found to be host-specific in nature. Further studies will reveal the discovery of a host-specific toxin in India.

Association of mycoplasmalike bodies with Launaea nudicaulis phyllody.

Summary Mycoplasma-like organisms were observed in thin sections cut from parts of Launaea nudicaulis plants with phyllody. It appears that they may be the causal agents of this malady, as no such bodies were observed in tissues from normal plants.

Mosaic disease of Chinese shoe flower (Hibiscus rosa-sinensis L.).

Summary A virus disease on Chinese shoe flower, hitherto not reported, has been described. It is transmitted by grafting and causes systemic infection only on Hibiscus rosa-sinensis . Diseased leaf expiants produced loose white calli on MS medium. The virus is designated “Chinese shoe flower mosaic virus”.

An Electron Microscope Study on the Size of Launaea Mosaic Virus

Summary Launaea Mosaic Virus has along thread-like particles, measuring from 750–930 nm. in length and 16–18 nm. in width.