Arbuscular Mycorrhizal Colonization Enhanced Early Growth ofMallotus paniculatusandAlbizia samanunder Nursery Conditions in East Kalimantan, Indonesia

Saridi Saridi,Weiguo Cheng,Dewi Wulandari,Keitaro Tawaraya

doi:10.1155/2014/898494

Abstract

Forest over logging, forest fire, forest conversion, and opencast mining have promoted deforestation in Indonesia, and reforestation is needed immediately. However, reforestation is limited by low seedling quality and production, and slow seedling growth in nurseries. Native tropical tree and fast-growing species,Mallotus paniculatusandAlbizia saman, are potential to promote the first rotation of reforestation. Arbuscular mycorrhizal (AM) fungi are known to promote nutrient uptake and plant growth. We examined the effects of two native AM fungi,Gigaspora decipiensandGlomus clarum, on the growth ofM. paniculatusandA. samanseedlings under nursery conditions. At harvest, after six months, we determined AM colonization, shoot dry weight, and shoot N and P concentration. Approximately 90% and 50% ofM. paniculatusandA. samanroots, respectively, were colonized by AM fungi, without any difference between the inoculation treatments.G. decipiensandG. clarumincreased shoot height, leaf number, shoot dry weight, and shoot N and P uptake of both species. A positive correlation was observed between N and P uptake and shoot dry weight. These results suggest that AM fungi are effective in accelerating nutrient uptake and plant growth, which will, in turn, promote reforestation and sustainable forest timber production.

Highlights

In Indonesia, deforestation is occurring rapidly owing to over logging, forest fire, forest conversion into agricultural land or oil rubber plantation [1], and opencast mining [2], and, immediate restoration is required by applying a comprehensive and systematic reforestation method
Shoot dry weight of M. paniculatus seedlings inoculated with G. decipiens and G. clarum was 53% and 28% higher than that of control seedlings six months after sowing, respectively (Table 1)
Seedlings inoculated with G. decipiens had higher shoot dry weight than those inoculated with G. clarum

Summary

Introduction

In Indonesia, deforestation is occurring rapidly owing to over logging, forest fire, forest conversion into agricultural land or oil rubber plantation [1], and opencast mining [2], and, immediate restoration is required by applying a comprehensive and systematic reforestation method. Natural forest recovery, in forestland used for bare opencast mining, requires several hundred years and consists of the initial, middle, and climax stages [3]. Pioneering and light-requiring species, such as leguminous trees, grasses, and shrubs, are established first [4] in the initial stage of forest succession, followed by gap-opportunistic species (Meliaceae, Dipterocarpaceae, and Flindersia spp.) in the middle stage, and shade-tolerant species in the mature or climax stage [5]. The preparation of seedlings of native tree species [6] and the selection of fast-growing leguminous species [7] with improved nitrogen (N), phosphorus (P), and potassium (K) uptake and biomass production are vital for the initial stage of reforestation. As an evergreen timber tree [9], this plant is an important pioneer species in Kalimantan, Indonesia, because it contributes to the aboveground biomass in secondary forests [10]

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