Volume 66, Issue 3
September 1967, pages 75-116
pp 75-82 September 1967
The carpel primordium comprises the midrib and marginal meristems. Activity in the marginal meristems results in the formation of short projections towards the adaxial side of the primordium. These projections represent the incipient laminal halves. Subsequently, rapid abaxial growth in the carpel leads to the displacement of the marginal meristems in an involute direction. Thus, the marginal meristems move closer and the abaxial tissues get adpressed due to involute growth. Another interesting result of rapid abaxial growth is the appearance of tissue projections (abaxial appendages) from the adpressed abaxial part. The abaxial appendages exhibit false margins but do not possess mariginal meristems, the component cells being highly vacuolated and enlarged. The loculus is formed by the expansion of the ventral surface lying between the marginal meristems which by this time transform into placental surfaces. At this stage the carpel can be resolved into midrib, loculus, incurved marginal placentae and adpressed abaxial appendages whose primary function appears to be development of stigmatic papillae at the terminal regions of the carpel. It is possible that the various types of simple carpels in the Ranales have diverged because of the different lengths their abaxial appendages have attained.
pp 83-86 September 1967
The utilisation of pollen size/style length ratios is promising in phylogenetic studies. Species possessing lower ratios are considered advanced. The principle applied to species of Tephrosia (Papilionaceae) serves as a good corroboratory evidence showing correlation with the cytological situation.
pp 87-91 September 1967
Experiments with the seeds and seedlings of three parents and their six hybrids revealed that parental and hybrid seeds did not differ significantly in their germinating capacity, while significant differences were seen in the rate of respiration. Leaf tissues failed to show significant differences in the rate of respiration. There did not seem to be any correlation between respiring capacity and growth rate.
Studies on the seedling characters, viz., seedling height, fresh weight, shoot to root ratio, total root length, leaf area and dry weight revealed that the early grand period of growth began soon after the germination and much differences were exhibited between parents and hybrids as early as the 10th day after germination in all characters studied, except shoot-root ratio and total root length. Hybrids attained relatively better growth during the early stages of development and gradually differences ceased to exist by 50th day. An exception to this trend was fresh weight.
pp 92-99 September 1967
A systematic study of the species of Aspergillus, Penicillum and Paecilomyces, occurring on pickled pelts, has been made. Penicillium purpurrescens, P. corylophilum, Paecilomyces varioti, Aspergillus fumigatus, A. unguis, A. terreus, A. niger, A. flavus, A. oryzae and A. ochraceous have been recorded for the first time on pickled pelts. Earlier records of moulds on tannery substrates have been presented.
pp 100-105 September 1967
Detailed chemical, optical and X-ray study of the green accicular amphibole occurring at the contact of the ultrabasic rocks with the granite gneiss is presented. It is shown that the mineral is a magnesium rich actinolite. The mode of occurrence and the chemistry of the mineral suggest that it has formed in the ultrabasic rock through a process of metasomatism deriving the required silica, alumina and lime for its formation from the bordering granite gneiss.
pp 106-116 September 1967
Sporogeneses, development of gametophytes, endosperm and embryo has been described in Rotula aquatica Lour.
The flowers are borne on few flowered terminal and subterminal racemes. The floral parts develop in an acropetal succession.
The anther archesporium is in the form of a plate of four to five cells. A mature anther consists of four wall layers, the innermost of these is the secretory tapetum with multinucleate cells. The endothecium develops fibrillar thickenings at maturity. The microspore tetrads are of tetrahedral, decussate and isobilateral types. Pollen grains are shed at two-celled stage.
The ovules are anatropous, unitegminal and tenuinucellar. The archesporium is hypodermal and cuts off a parietal cell. The megaspore tetrad is of linear type. The chalazal megaspore is functional but sometimes any one of the remaining megaspores may also enlarge. The embryo sac develops according to Polygonum type. An integumentary tapetum is differentiated at the four-nucleate stage of the embryo sac.
Endosperm is cellular and Myosotis-type. Chalazal and micropylar haustoria are organized; the chalazal haustorium is more aggressive. Embryo development is of Chenopodiad type.