Ficus Retusa Research Articles

The Seabirds of Nakanokami-shima, South Ryukyu, Japan

Nakanokami-shima was designated a national monument in 1972 because of its important for breeding seabirds, though the seabirds of the island were very poorly known. In this paper we present the information on the breeding species and their current status. Observations were made over a ten years period from 1975 to 1984.Seven species of seabirds were found to breed on the island. All were summer visitors, except for the Brown Booby which may be a resident.1. Bulwer's Petrel, Bulweria bulwerii. Bulwer's Petrel was not known to breed on the island until we captured and ringed 2 adults on 2 July, 1981, both of which had fully grown brood patches, and 2 more adults on 4 July, 1982, both of which were incubating. In 1982, 1983, and 1984 the petrels bred at the same locations shown in Fig. 1. The petrels bred gathering in small numbers and laid under rock, Sixty-six adults were ringed from 1981 to 1984 and it seems that the breeding population is fewer than 100 birds.2. White-faced (or Streaked) Shearwater, Calonectris leucomelas. Many nest holes of the White-faced Shearwaters were widely distributed on gentle slopes in grassplateau in the centre of the island. Some birds incubated on bare ground under dwarf 'Gajumaru', Ficus retusa, and others incubated under large rocks. We could not estimate their population.3. Brown Booby, Sula leucogaster. The main colonies, which were used by almost all the birds, were found annually at areas A, B, C, and D shown in Fig. 2. On Nakanokami-shima Brown Boobies nested on ridges and on steep cliffs. Few birds nested in the rocky zone near the shore. Before noon on 3 July, 1981, a Maritime Safety Agency Helicopter flew over the eastern part of the island, surprising the settled birds and causing them to take flight one after another. It was possible at that time to make a total count and 250 birds were counted. Since the breeding pairs were taking care of chicks at that day, some parents were probably absent offshore. Clearly the population was larger than 250. A chick ringed on 29 June, 1980, at the main colony was recaptured at the same place on 21 August, 1983. The bird was in adult plumage, but was not breeding. This recovery record indicates that non-breeding immatures are also included among those attending the main colonies. Table 1 shows the results of an intensive search for nests during the breeding season of 1984. Nests on inaccessible cliffs in areas A-D were of course omitted. The annual breeding population was estimated approximately as about 200 to 500 birds.4. Red-footed Booby, Sula sula. This species was not known to breed in Japan before 1975, when we discovered a breeding pair on 27 August, 1975. The parent incubated one egg and its nest was builted on the canopy of dwarf 'Gajumaru' bush in area A in Fig. 2. On 24 June, 1976, 3 adults and 2 chicks were ringed at the same place, and on 30 June, 1977, one downy chick and parent were found again at the same place as in 1975. On 13 July, 1982, two fledglings and one adult were seen on the cliff in area E in Fig. 2.5. Bridled Tern, Sterna anaethetus. This, species was not known to breed in Japan until we found its breeding at the island on June, 1980. The Bridled Tern settled rocky zone near the shore, placing their eggs in the shelter of rocks. The locations of colonies in 1983, and 1984 are shown in Fig. 3. This tern is apparently an inshore feeder, remaining usually close to the colony. The estimated numbers were 120 birds in area A, and 40 in area B on June 30, 1980, about 1000 in area A, and 100 in area B on 2 July, 1981, and about 650 in area, A, and 50 in area B on 2 July, 1982. Since 1981 the numbers have increased markedly. The birds in attendance at these areas were in adult plumage, however considerable numbers of non-breeding, presumably immature, birds may make up part of these totals.

Clonal Variability in Response to Light Intensity during Growth and to Subsequent Dark Storage of Ficus benjamina and Ficus retusa

Abstract Three clones of Ficus benjamina L. and one clone of Ficus retusa L. foliage pot plants were raised under 3 different light intensities. Variations in the morphological development of the clones in response to light intensity were recorded. Leaf abscission from these plants was followed at the end of 2 weeks of dark storage, and during a subsequent period of one month in a simulated home environment. In unstored plants, only low levels of leaf drop were observed. Leaf abscission was stimulated strongly during dark storage and in subsequent indoor environment. The degree of dark storage-promoted leaf abscission, and the response pattern to light intensity during the production phase, with regard to leaf drop during simulated home conditions, showed a clear clone-dependent specificity. It is concluded that the genetic background is a major factor affecting storability and subsequent performance under simulated home conditions.

Occurrence of Gynaikothrips uzeli injurious to Ficus retusa and its chemical control

Occurrence of <i>Gynaikothrips uzeli</i> injurious to <i>Ficus retusa</i> and its chemical control

The effect of container size and aeration conditions on growth of roots and canopy of woody plants

Studies were made on the effect of container size on the growth of Ficus retusa, Pistacia lentisucus and Dodonea viscosa. The larger the container, the larger was the plant. The ratio of plant weight to unit of container-volume decreased with increasing size, whereas the ratio of plant weight to unit surface area remained more or less constant with changing size of container. Aeration of 10-liter containers using 3 methods to increase the surface area of the mixture by 60% while reducing the volume by 40%, increased growth by as much as 165%. Especially enhanced growth was achieved when the structure of the root system was not changed by aeration devices. Root growth was enhanced most in the lower section of the containers. The ratio root-weight: container-volume increased up to 340%, whereas the ratio root-weight: mix-surface area increased by only 100% at the most. These results, and others, indicate that most of the thin roots (or root activity) of woody plants grown in containers are concentrated in the periphery of the container, whereas the roots in the center serve mainly as connectors between the main and peripheral roots. It is suggested that the root system in the containers changed the ratio between the 3 soil phases by decreasing the gaseous phase, mainly in the upper part of the container, and that this phenomenon is a major contributor to the low efficiency of the container-volume usage. Correction can be best achieved by increasing the outer surface of the mixture rather than by using a better aerated mixture.

The effect of container shape on the development of roots and canopy of woody plants

The branching and spread of roots in containers was studied in a shallow rooting plant ( Erythrina corralodendrum) and in a deep-rooting plant (oak, Quercus ithaburensis). In the Erythrina, the weight of the roots was found to decrease towards the base of the container. Sixty percent of the root system was laterals, which were evenly distributed throughout the container. In the oak, a higher root weight was found in the lowest third of the container than in the 2 upper thirds. Lateral roots comprised 14% of the complete root system, mostly in the base of the container. Severe pruning of oak roots resulted in a ratio of main-root/lateral roots comparable to that found in unpruned Erythrina. The growth and distribution of roots of plants with different growth characteristics in containers of various shapes, e.g. deep and narrow, or shallow and wide as compared to regular shape containers, were studied. Thus, in Ficus retusa, which has a shallow root system, the development of roots was stimulated in a shallow and wide container, but roots and canopy were restricted in a deep and narrow container. In Pistacia lentiscus, which has a deep root system, planting in a shallow and wide container resulted in retarded canopy and roots, while growing the same plant in a narrow and deep container showed a stimulated root growth. In Dodonea viscosa, whose root system is naturally deep and tends to spread laterally, a slight retardation of the root development was found when it was grown in a shallow and wide container. When grown in a deep and narrow container, canopy and root growth were stimulated. The study indicated that growth tends to be stimulated when there is a mutual matching between the natural growth pattern of roots and the shape of their container.

On the Enzymes contained in the Sap of Ficus retusa

On the Enzymes contained in the Sap of Ficus retusa