Volume 81, Issue 2
February 1975, pages 61-100
pp 61-66 February 1975
The distinguishing characters of six species of stomatopods being recorded for the first time from the coastal waters of Andhra Pradesh are given.
pp 67-74 February 1975
Simulium (Eusimulium) ghoomense, sp. nov. is illustrated and described from the Darjeeling area of India, and the group-status of the species is critically discussed.
pp 75-82 February 1975
Blastokinetic movements during embryogenesis inChrysocoris purpureus have been described. This movement (which appears to be inevitable) results in bringing the inner layer of the growing embryo in close apposition with the yolk and facilitates later utilisation. The variation in the blastokinetic movement and the manner in which it is accomplished in a majority of insect species is discussed.
pp 83-90 February 1975
The development of the shoot apex is studied from the globular embryo onwards. The cotyledonary primordia are initiated by periclinal divisions on two lateral flanks of the terminal part of the embryo. Epicotyl apex is recognisable between the cotyledonary primordia at early torpedo stage. The mature embryo in the seed shows well developed primary rachis with buttresses of secondary rachis primordia of bipinnate compound leaf. The mature shoot apex has two tunica layers covering the corpus. The shoot apex shows distinct cytohistological zones,viz., the tunica, the central mother cells zone, the pith rib meristem and the flanking zone. The plastochronic cycle is divisible into minimal, midplastochron and the maximal phases.
pp 91-100 February 1975
The shoot apex ofNymphaea stellata Willd. shows a tunica-corpus organization with a cytohistological zonation. The tunica is single-layered and the corpus exhibits three zones, the corpus mother cells zone, the flanking zone and the pith-rib meristem zone. The plastochron is divided into five stages based on the plastochron index—the minimal, early post-minimal, late post-minimal, pre-maximal and maximal. A cambium-like zone is developed proximal to the corpus mother cells zone in apices at the post-minimal stages, which contributes to the increase in height of the apex.
The root apex shows a transversal meristem, which is in the form of a curved plate of cells. This cell plate gives rise to the central cylinder, cortex and epidermis proximally, and the columella and periheral region of the root cap distally.