Drought stress is one of the most common abiotic stress in agriculture. The use of antitranspirant agents to reduce the effect of drought stress on crops has been considered as a potential method. The application of chitosan as an antitranspirant agent has been reported to be effective in several crops. This study was aimed to analyze the effect of chitosan foliar application for maintaining the growth of lettuce under drought conditions. Three concentrations of chitosan (0.2 g/L; 0.4 g/L; 0.6 g/L) were tested in this study. The parameter observed were the height of the lettuce, number of leaves, leaf length and the width, root length, as well as fresh and dry weight. The drought condition without chitosan application reduced the growth of lettuce in all parameters. Chitosan application at 0.2 g/L was able to reduce the effect of drought stress and maintain the growth of lettuce. However, higher chitosan concentration applications (0.4 g/L and 0.6 g/L) were observed to reduce the growth of lettuce. Based on this study, chitosan was reported to reduce the effect of drought stress in lettuce. As chitosan affects the transpiration process by stomatal closure, a higher concentration of chitosan may also affect the photosynthesis process leading to growth inhibition.

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Abstract. Wiryono, Sriwahyuni, Winanda GA, Saprinurdin, Nurliana S. 2019. The diversity of useful plants and botanical knowledge of the Rejang Tribe in Kepahiang District, Bengkulu Province, Indonesia. Biodiversitas 20: 3599-3607. The rural people derive multiple benefits from the highly diverse plants in their traditional gardens and the nearby natural forests. However, the conversion of natural forests and traditional gardens into monoculture plantations in many areas has reduced the plant diversity, which in turn has also reduced the botanical knowledge, especially among the younger generation. This study was conducted to know: (i) the diversity of plant species used by the people of Rejang tribe in Kota Agung Village, Kepahiang District, Bengkulu Province, Indonesia, (ii) the correlation between age and botanical knowledge, and (iii) the effect of gender on the botanical knowledge. Data were collected through interviews with five key informants and 68 villagers, and the data were analyzed qualitatively and quantitatively using t-test and regression analyses. The results showed that the Rejang people in Kota Agung Village used 130 plant species for 12 different purposes. The three top use categories were food, medicine, and ornament. The botanical knowledge was positively correlated with age, and women had better botanical knowledge than men, presumably due to the longer time they spend in taking care of the homegardens. This study confirms the worldwide trend that there is a decline in botanical knowledge among young people.

Abstract. Wirnoyo, Lukman AH, Nurliana S. 2022. The species diversity and composition of seedlings for degraded land rehabilitation in different phytogeographical regions in Indonesia. Biodiversitas 23: 5771-5781. Forest clearing and conversion into cropland without implementing conservation measures have caused land degradation. The total area of degraded land in Indonesia is 14 million hectares. The responsible institution for land rehabilitation in Indonesia is Balai Pengelolaan Daerah Aliran Sungai dan Hutan Lindung (Agency for Watershed and Protection Forest Management), abbreviated as BPDASHL. This study aimed to analyze seedlings' species diversity and composition for degraded land rehabilitation provided by six BPDASHLs located in different phytogeographic regions, i.e., Sunda Shelf, Wallacea, and Sahul Shelf. Data were collected through questionnaires distributed to BPDASHL offices in Papua, West Papua, Gorontalo, Bangka Belitung Islands, Riau, and Aceh. They were analyzed to determine the species richness, indexes of species diversity, equity, and similarity. The clustering of sites based on species composition was done using a dendrogram. This study found that the species richness of seedlings in each site ranged from 25 to 47, the diversity index of Shannon from 2.39 to 2.96, and a Simpson diversity index from 0.80 to 0.94. The species composition differed from one site to another, with similarity indexes of Bray-Curtis and Jaccard of < 0.35. The dendrogram separated western Indonesia (Sunda Shelf) from eastern Indonesia (Sahul Shelf and Wallacea), except for Bangka Belitung Islands, which was clustered in eastern Indonesia despite its location in western Indonesia. Three study sites had more native dominant species, while the other three had more introduced dominant species. We recommend that more native species of seedlings should be provided.