Fungi on decomposing spadix of Pandanus fascicularis

Investigation into fungi causing deterioration of different parts of the shoot have been made by Hogg and Hudson (1966), Hudson and Webster (1958), Kamal and Singh (1970), Webster (1957) and Yadava (1966). Such studies on the modified part of the shoot are scarce and scanty. Undoubtedly, some fragmentary reports in connection with the floral infection of one or the other part of the flower, though available; yet are the local interest (Plate and Schineider, 1966; Schonbeck, 1967 and Welfswinkee, 1966). The present study is an attempt to explore the organisms associated with the spadix of Pandanus fascicularis when it is still enclosed within the spathe and their role in its decomposition.

Spadix of Pandanus fascicularis still enclosed within the spathe were plucked from the Janaki ghat, Ayodhya, district Faizabad and were brought to the laboratory in sterilized brought mouth polythene bottles. The were then incubated in Petri-dish moist chamber (15cm) at room temperature. Sterilized water were added to the moist chamber when needed. The observations were made on the 3rd, 5th, 10th, 15th, 20th, 30th,40th and 50th day of incubation and the fungi were recorded by direct observation of maturre fruit bodies under the dissecting microscope, where their presence and absence was the criterion of colonisation of the organisms on different days of incubation. 

Perusal of the data in the Table I shows the presence of only deuteromycetes comprising Aspergillus species, Curvularia lunata and Trichothecium roseum on decomposing spaxis of P. fascicularis. Of Aspergillus  species, A. fumigatus, appeared on the 3rd day and was accompanied by A. aculeatus A. flavus, A. phoenicis and A. ochraceous on the 5th day. Four amongst them were recorded upto 15th day while one (A. flavus) persisted till the 20th day of incubation. Curvularia lunata  appered on the 10th day and persisted upto 50th day. It was accompained by Trichothecium roseum on the 30th day which persisted till the last day of observation.

      Table I. Species on Spadix incubated upto fifty days.

Fungal Species	DAYS OF OBSERVATIONS
	3	5	10	15	20	30	40	50
Aspergillus aculeatus	-	+	+	+	-	-	-	-
A. flavus	-	+	+	+	+	-	-	-
A. fumigatus	+	+	+	+	-	-	-	-
A. ochraceous	-	+	+	+	-	-	-	-
A. phoenicis	-	+	+	+	-	-	-	-
Curvularia lunata	-	-	+	+	+	+	+	+
Trichothecium roseum	-	-	-	-	-	+	+	+

    

Nature and environmental conditions of the microhabitat exercise a broadly selective effect upon the kind of microorganisms that enter into competition for the substrate (Garrett, 1963). Definite correlation appears between the substrate and type group of fungi colonising it. Abundance and the rare occurrence of the species are governed by the composition of the substrate and their association with micro-entities which may be stimulating or antagonistic to their growth at same nutritional level. Deuteromycetes are a group of indefinite affinity with varying nutritional requirements. Ecologically, however, sugar fungi include a number of imperfect fungi specially the species of Aspergillus and Penicillum (Cochrane, 1958). The species of this group are basically considered as cellulose decomposing (Siu and Reese, 1953). In the present investigation, the early appearance of aspergilli may be deu to the ability to utilise simple sugars and rapid spore germination (Table. I). Carter (1958) reported that a diffusible heat-labile substance produced by bacteria, isolated from pellets inhibited the growth of phycomycetes in culture. The absence of phycomycetes from the decomposing spadix may be affected by the antagonistic effect of bacteria. Occurrence of  C. lunata and T. roseum  during the last days days of incubation may be ascribed to thier ability to utilise cellulose (Siu and Reese, 1953).

The successional pattern of fungi, associated with the decomposing unbloomed spadix of P. fascicularis was studied. Species of Aspergillus appeared 1st, followed by Curvularia lunata. Trichothecium roseum appeared late and persisted till the last day of observation. (See original)

Cited this as: Kanaujia R.S. and C.S. singh (1975): Fungi on decomposing spadix of Pandanus fascicularis. Botanique. VI(1):11-15.