Volume 61, Issue 6
June 1965, pages 291-330
pp 291-295 June 1965
pp 296-308 June 1965
The root apical organization of eight species of plants belonging to the Compositae exhibit three types of structural configuration.
The cap is considered as having two regions, the columella and the peripheral part with their separate initiating regions.
The modes of widening of the columella is discussed.
On the basis of the structural configurations met with in these root apices a phylogenetic line in their evolution is put forwardtentatively.
The cytohistological state of the root apices studied supports the concept of a quiescent centre and a meristematic zone. This study also shows that there are four peak periods for division of cells during a day of 24 hours in root tips ofZinnia.
pp 309-315 June 1965
Results of a solution culture experiment conducted to find out the efficiency of phosphorus absorbed during various growth stages of an early duration and a medium durationindica rice show that, under normal supply, phosphorus absorbed during the tillering stage is most efficiently utilized for grain production and is adequate to give an optimal grain yield. Phosphorus absorbed beyond this period tends to accumulate in the grain, straw and root with no advantage to the grain yield. These results suggest that early application of phosphate fertilizers is desirable in rice farming.
pp 316-325 June 1965
The vascular anatomy of the flower ofLilaea scilloides has been described in this paper. The flowers are polygamous. Each perfect flower consists of a perianth segment, a sessile stamen and a closely appressed carpel. The perfect flower ofLilaea, that has been considered by some authors as a secondary inflorescence consisting of one staminate and one pistillate flower, is regarded here as a normal bisexual flower.
The presence of three dorsal bundles in the gynoecium ofLilaea suggests its tricarpellary nature and the so-called monocarpellary condition appears to have been brought about by suppression of two of the three carpels. It appears logical that the ventral strand, which supplies the solitary ovule, is the fusion product of the ventral bundles of the only surviving carpel.
The present investigation also gives some support for segregatingLilaea to a separate family.
pp 326-330 June 1965
Alternaria porri, the causal organism of Purple Blotch disease, lives over from one season to the next as mycelium and spores in onion leaves and seed stalks left as debris on the surface of the soil from the last harvest. The diseased debris loses its viability when buried two inches or more, deep in the soil, but diseased debris retains its viability for eight and nine months when exposed to the weather and kept in the laboratory rooms.
The viability and infectivity tests with dried cultures and test-tube cultures have shown that fungus can be kept pure as dried cultures for a period of 12 months or more.