Benjamin O. AKPOR, Anthony I. OKOH, Gbolahan O. BABALOLA

Culturable microbial population dynamics during decomposition of Cola nitida leaf litterds in a tropical soil setting

Çürümekte oian Cola nitida yaprak artıklarında bulunan kültüre alınabilir aerobik, heterotrofik bakteri ve fungus dağılımı ve populasyon dinamikleri, Şubat 2002 ve Ocak 2003 tarihleri arasında çalışılmıştır. Bu amaçla, standart çöp-torba ve mikrobiyal kültivasyon teknikleri, dışa kapalı ve kapalı olmayan ortamlar düzeneğinde kullanılmıştır. Ayrıca, organik karbon ve toprak pH' sı takip edilmiştir. Bakteri sayıları $6.0x10^5$ ve $8.1x10^7$ cfu/g yaş artık veya toprak ağırlığı arasında değişirken, fungal sayımlar $10^3—10^4$ cfu/g yaş artık veya toprak ağırlığı civarında olmuştur. Bakteri ve fungus sayılan en çok yağmurlu sezon içerisindeki aylarda olmuş, bunun dışındaki aylarda düşmüştür. Bakteri çeşitlilik indeksi 0.42 ve 1.69, fungal çeşitlilik indeksi ise 0.56 ve 2.54 arasında değişmiş ve toplam onsekiz kültüre alınabilir bakteri ve ondört fungal strain bulunmuştur. Yaprak artıklarında bulunan organik karbon miktarı toprakta bulunandan devamlı olarak yüksek bulunmuş, yaprak artıkları için % 13.42 ve 59.00 arasında değişirken, toprak örnekleri için % 4.02 ve 14.76 arasında seyretmiştir. Toprak örneklerinde pH, 5.3 ve 7.98 arasında bulunmuştur. Cola nitida yaprak artıklarının kapalı veya kapalı olmayan ortamlarda dekompozisyonun, kültüre alınabilir mikrobiyal ortamın stabilitesini önemli ölçüde etkilemediği sonucuna varılmıştır..

Anahtar Kelimeler:

bakteriler, mantar, Cola nitida, ölü örtü, ayrışma, bitkisel ürün artıkları, toprak tipi (iklimsel), tropik topraklar

Tropik toprak koşullarında Cola nitida yaprak artıklarının parçalanması sürecinde kültüre alınabilir mikrobiyal populasyon dinamikleri

The culturable aerobic heterotrophic bacterial and fungal distributions and population dynamics during decomposition of koianut leaf litters were investigated between February 2002 and January 2003 using standard litterbag studies and microbial cultivation techniques in a confined and unconfined setting. Organic carbon and soil pH were also monitored in the experimental plot. Bacterial counts ranged between $6.0x10^5$ and $8.1x10^7$ cfu/g wet weight of litter or soil, while fungal counts were of the order of $10^3—10^4$ cfu/g wet weight of litter or soil. Counts of bacteria and fungi were highest during the rainy season months and reduce on either sides of the rainy season divide. Bacteria diversity index ranged between 0.42 and 1.69, while fungal diversity index varied between 0.56 and 2.54, and a total of eighteen culturable bacterial and fourteen fungal strains were identified. The organic carbon contents of the leaf litters were consistently significantly (p < 0.05) higher than those of the soils in the experimental plot and ranged between 13.42 and 59% for the leaf litter and 4.02 - 14.76% for the soil samples. pH of the soil samples were observed to vary between 5.3 and 7.98. We conclude that decomposition of koianut leaf litters in a confined or unconfined setting does not appear to significantly affect the stability of the culturable microbial milieu.

Keywords:

bacteria, fungi, Cola nitida, litter (plant), decomposition, crop residues, soil types (climatic), tropical soils,

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