Judul: Morphotype diversity and isolation of shorea spp. ectomycorrhizal fungi at KHDTK Haurbentes Research Forest Jasinga, Bogor
Abstrak: Shorea spp. bersimbiosis secara obligat dengan cendawan ektomikoriza. Biologi ektomikoriza Shorea spp. belum banyak dilaporkan sehingga penelitian terhadap struktur kolonisasi ektomikoriza dan isolasi cendawan pada Shorea spp. perlu dilakukan. Penelitian ini bertujuan untuk menganalisis morfotipe dan mengisolasi cendawan ektomikoriza pada Shorea spp. di KHDTK Haurbentes Jasinga, Bogor. Hasil analisis morfotipe ektomikoriza dari 45 sampel akar diperoleh 10 morfotipe yakni irregularly pinnate black, irregularly pinnate dark brown, irregularly pinnate light brown, monopodial pinnate dark brown, monopodial pinnate light brown, monopodial pyramide dark brown, monopodial pyramide light brown, unramified-simple black, unramified-simple dark brown dan unramified-simple light brown. Sebanyak 15 isolat berhasil diisolasi dari morfotipe irregularly pinnate dark brown, irregularly pinnate light brown, monopodial pinnate light brown dan unramified-simple light brown. Sebanyak 8 dari 15 isolat yang berhasil diisolasi, diduga sebagai cendawan ektomikoriza karena isolat tersebut tidak bersporulasi, memiliki hifa septat dan beberapa isolat membentuk klamidospora. Kata kunci: Ektomikoriza, Haurbentes, Morfotipe, Shorea spp., Shorea spp. are obligately associated with ectomycorrhizal fungi. Ectomycorrhizas on Shorea spp. have not been extensively studied, especially biological aspects of the symbiosis. The aim of this research was to analyze root morphotype on Shorea spp. and isolate of the ectomycorrhizal fungi at KHDTK Haurbentes Research Forest Jasinga, Bogor. Based on root morphotype analysis from 45 ectomycorrhizal root samples of KHDTK Haurbentes were obtained 10 morphotypes. They were irregularly pinnate black, irregularly pinnate dark brown, irregularly pinnate light brown, monopodial pinnate dark brown, monopodial pinnate light brown, monopodial pyramide dark brown, monopodial pyramide light brown, unramified-simple black, unramified-simple dark brown and unramified-simple light brown. A total of 15 fungal isolates were succesfully obtained from morphotypes such as irregularly pinnate dark brown, irregularly pinnate light brown, monopodial pinnate light brown and unramified-simple light brown. A total of 8 out of 15 isolates might be ectomycorrhizal fungi because they did not sporulated, septate hyphae and sometimes form chlamydospore. Keywords: Ectomycorrhiza, Haurbentes, Root Morphotype, Shorea spp.
Keyword: Ektomikoriza, Haurbentes, Morfotipe, Shorea spp.

Judul: Ektomikoriza pada Shorea spp. di Kawasan Hutan Haurbentes Jasinga Bogor
Abstrak: Shorea spp. are member of Dipterocarpaceae family. They are tropical rainforest plant which have high economic value due to high quality of their timber and non-timber products. Ectomycorrhizal fungi had been used as biofertilizer for Shorea spp. This research aimed to study the ectomycorrhizal root morphotypes, isolation and identification of ectomycorrhizal fungi associated with Shorea spp. Sixty ectomycorrhyzal root tip samples were taken from Shorea saminis (plot 1), Shorea palembanica (plot 2), and Shorea stenoptera (plot 3). The results showed that all plants associated with ectomycorrhiza, with percentage of roots colonization around 60%. The highest abundance of associated root was found at plot 2, followed by plot 3, and the lowest was found at plot 1. Data of root morphotype analysis indicated that there were 5 major of root tip morphotypes. There were brown irregular pinnate, black irregular pinnate, silver irregular pinnate, brown monopodial pinnate, and black monopodial pinnate. Brown irregular pinnate was the dominant root tips morphotypes with the frequency was 60.9%. A total of 15 different isolates were isolated from 3 ectomycorrhizal root tips morphotypes, e.g. brown irregular pinnate, black irregular pinnate, and brown monopodial pinnate. All of the isolates were mycelia sterilia. Some of the fungi had special mycelial characteristics by producing hyphal anastomosis and produce intensive branching mycelium.
Keyword: mycelia sterilia, Shorea., intensive branching mycelium, ectomycorrhyzal root tip morphotype, Anastomosis

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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