Volume 83, Issue 5
May 1976, pages 177-219
pp 177-184 May 1976
Evaluation of a few collections from rice germplasm under field and inoculated conditions showed some selections resistant or tolerant to the nematode. The duration of endoparasitic development was 20 days in susceptible varieties and 32 and 48 days in tolerant and resistant varieties. The reproduction and egg mass production by the nematode were inhibited in the resistant and tolerant varieties.
pp 185-195 May 1976
The assimilatory nitrate reductase [NAD (P) H: nitrate oxidoreductase, EC 126.96.36.199] of the nitrate-utilizing yeastCandida utilis was prepared in soluble form from cells grown aerobically with nitrate as the nitrogen source, and some of its properties studied. The enzyme is cytoplasmic in intracellular distribution and its activity is NAD (P) H-dependent. The enzyme utilized both NADH and NADPH as electron donors but not reduced viologen dyes, flavins and other reductants. Flavin compounds, at higher concentrations, decreased the enzyme activity, while at very low concentrations, FAD (10−5 M) showed little stimulation.
The optimal activity of the enzyme was obtained when the reaction was carried out for 10 min at 37° C at pH 7·0 with 20 mM KNO3, 0·1 mM NAD (P) H, 0.01 mM FAD and 140 µg enzyme protein.
Complete loss of enzyme activity was observed on exposure to 50° C for 3 min. pHMB, cyanide, azide and EDTA, in that order, inhibited the enzyme activity effectively. The inhibition caused by pHMB was largely reversed by DTT.
pp 196-201 May 1976
The trends of infestation ofHaplothrips ganglbaueri onOryza sativa and the weedEchinochloa crusgalli in paddy fields are discussed, along with its biological and taxonomical aspects.
pp 202-206 May 1976
The new genera and speciesAraeothrips longisetis andSalothrips indicus are discussed in this paper.
pp 207-209 May 1976
Structural peculiarities of roots developed from tissue culture of gamma-irradiated seeds ofCajanus cajan have been compared with unirradiated roots, based on anatomy. Internal perturbation as a result of irradiation was marked in 10 kR-treated roots in which each xylem group was reduced to a single metaxylem vessel with fewer or no protoxylem elements, secondary growth was absent consequent on loss of cambium and the phloem was transformed into fibrous tissue.
pp 210-219 May 1976
Barnacle nauplius before achieving a sedentary cyprid stage undergoes six transformations within a period of 7 to 15 days since its release from a parent body. The larval metamorphosis ofChthamalus malayensis P. was examined under controlled laboratory conditions to describe each of its six nauplii and cyprid larva. Highly setulose naupliar appendages, absence of paired posterior carapace spines, sculpturing of polygons on shell, presence of 4 pairs of abdominal spines, presence of pecten of teeth on labrum of early larvae and its subsequent disappearance are some of the important characteristics that separate these larvae from many other species so far described. The study again emphasises the fact that the larval development amongst cirripedes is very uniform.