Buletin Kebun Raya

1-16

Authors: Aldi Rahman Hakim, Dorly Dorly, Sri Rahayu

Hoya spp. (Apocynaceae: Asclepiadoideae) has differences in leaf type, there are succulent and non succulent leaf types. Anatomical structure of Hoya spp. leaf has not been widely studied, especially for the non succulent type. The aims of this research were to explore the diversity and relationship of non succulent Hoya, based on leaf anatomical characters represented by eight species i.e. H. bandaensis, H. campanulata, H. chlorantha, H. cilliata, H. coriacea, H. coronaria, H. densifolia and H. multiflora. Hoya leaf anatomical characters were observed on the paradermal and transversal section and analyzed by using IBM SPSS version 19 sotfware for cluster analysis. According to the paradermal observation, stomata were present at lower surface (hypostomatic) for all species, and amphistomatic (both surface) for H. densifolia. The type of stomata is cyclocytic for all species. Clustered stomata were found in H. coriacea. Observation on transversal section showed that all of species has the normal structure i.e cuticula, upper and lower epidermis, palisade parenchyma and spongy parenchyma with the variation in the layer thickness. The cluster analysis resulted four groups at distance scale 19. Each group has specific characters. The first group has trichomes on both sides of the leaf surface. The second group has amphistomatic stomatal. The third group has thin leaves. The fourth group has the widest stomata.

27-36

Authors: Yayan Wahyu C. Kusuma, D.O. Pribadi, Y. Isnaini

Ramin (Gonystylus bancanus) is one of the major timber species that facing high exploitation in Indonesia. This species can only be found on a specific peat swamp habitat, thus it confines its distribution. Information on its current population and microhabitat characteristics is relatively limited. Here, we investigated natural population and microhabitat of ramin in a peat swamp area in Riau Province using random transects consist of 46 (100m2) sampling plots. Forty-eight individuals of ramin were found in which 46 of these belonged to G. bancanus, while the other two were different species. The estimated population density of ramin in this area was 7.18±2.75 individuals/ha i.e there were approximately seven individuals in each one-ha area of study. The population structure of ramin showed a J-shaped curve bearing many large old trees with few saplings without any seedlings. The microhabitat was investigated using the Discriminant Function Analysis (DFA) and Canonical Analysis, generating two significant variables that discriminated three groups of the population.

58-73

Authors: Putra Hafiz, Dorly Dorly, Sri Rahayu

Hoya has two types of leaves, succulent and non succulent. Succulent plant adapted well in extreme conditions, especially during dry period. Anatomical characters can be used to identify, classify, and determine plant relationship. The aims of this research were to identify anatomical character of succulent Hoya’s leaf and to determine their relationship. Ten examined species Hoya spp. (H. diversifolia, H. latifolia, H. dolichosparte, H. bilobata, H. lacunosa, H. verticillata, H. purpureofusca, H. kuhlii, H. oblanceolata, and H. micrantha) showed anatomical similarity in their epidermal layer, hipodermal, mesophyl, and the absence of sponge tissue at mesophyl. However, there are diversities among the species. Based on paradermal section of the leaf, two types of stomata were only found at the abaxial side, individual stomata and both individual and stomatal cluster. Hoya diversifolia has the smallest stomatal size, while Hoya latifolia has the biggest. Hoya lacunosa has the lowest stomatal density, while Hoya bilobata has the highest. Hoya diversifolia, Hoya lacunosa, and Hoya oblanceolata have the lowest stomatal index, while Hoya bilobata has the highest. Observation on transversal section showed that Hoya purpureofusca has the lowest leaf thickness, while Hoya kuhlii has the highest. The hierarchical cluster analysis based on anatomical leaf characters showed different patterns of relationship which diversed as three groups at relationship scale 15.