Research Article ISSN 2250-0480 VOL 4/ISSUE 1/JAN-MAR 2014 OCCURRENCE OF MYCORRHIZAE IN SOME SPECIES OF CAREX (CYPERACEAE) OF THE DARJEELING HIMALAYAS, INDIA *ASOK GHOSH 1, SHEKHAR BHUJEL 2 AND GAUR GOPAL MAITI 3 *1Department of Botany, Krishnagar Govt. College, Nadia, West Bengal, India 2Department of Botany, Darjeeling Govt. College, Darjeeling, West Bengal, India (Presently DTR&DC, Tea Board, A.B. Path, Kurseong, West Bengal, India) 3Department of Botany, University of Kalyani, Kalyani, West Bengal, India ABSTRACT The Cyperaceae (sedge family) have generally been considered non-mycorrhizal, although recent evidences suggest that mycotrophy may be considerably more widespread among sedges than was previously realized. In this study, 28 in situ populations of 12 species of Carex L.(C. myosurus Nees, C. composita Boott, C. cruciata Wahl., C. filicina Nees, C. inanis Kunth, C. setigera D. Don, C. insignis Boott, C. finitima var. finitima; C. fusiformis Nees subsp. finitima (Boott) Noltie, C. teres Boott, C. longipes D. Don ex Tilloch and Taylor, C. nubigena D. Don ex Tilloch and Taylor and C. rochebrunii subsp. rochebrunii; C. remota Linnaeus subsp. rochebrunii (Franchet and Savatier) Kükenthal) occurring in the Darjeeling Himalayas were surveyed. Mycorrhizal infection by VAM (Vesicular Arbuscular Mycorrhiza) fungi was found in roots of 9 species (C. myosurus, C. composita, C. cruciata, C. filicina, C. inanis, C. setigera, C. finitima, C. teres, and C. nubigena ) and appears to occur in response to many factors, both environmental and phylogenetic. In non-mycorrhizal species, a novel root character, the presence of bulbous-based root hairs, was identified. Key words: Carex, Cyperaceae, vesicular arbuscular mycorrhiza (VAM), mycotrophy, root hairs 1. INTRODUCTION Mycorrhizal association has been reported in most of group. The non-mycorrhizal nature of Carex the families of the modern day taxa, but there have coriaceae Hamlin and Uncinia divaricata Kük., even also been exceptions as Brassicaceae, Cyperaceae, under extreme phosphorus deficient condition Juncaceae, which are assumed to be non-mycorrhizal tempted (Powell, 1975) to conclude sedges among (Hirsch and Kapulnik, 1998). Sedges, due to their non-mycorrhizal groups. Sedges like Carex flacca disturbed habitat condition were long considered as Schreb , C. mertensii Prescott ex Bong. and Cyperus non-mycorrhizal (Newman and Reddell, 1987). rotundus Linn. are not benifitted by mycorrhizal Harley and Smith (1983) mentioned Cyperaceae as association and have maximum biomass in absence non-mycotrophs and further confirmation was given of this association (Muthukumar et al. 1997; Titus by Bagyaraj et al . (1979) when no colonization was and del Moral, 1998; Vander Heijden et al. 1998). reported on Cyperus eleusinoides Kunth. Moreover, Moreover lack in mycorrhizal association enhances further works on mycorrhizal association by Koske the competitive ability of plants (Titus and del and Halvorson (1981), Malloch and Malloch (1982), Moral,1998). In spite this assumptions that sedges and Brundrett and Kendrick (1998), Louis (1990) are non-mycorrhizal, there have been several reports also reported the absences of association in this L - 1 Life Science Botany Research Article ISSN 2250-0480 VOL 4/ISSUE 1/JAN-MAR 2014 on mycorrhizal association in sedges (Harley and hairs were negatively correlated with mycorrhizal Harley, 1987; Tester et al. 1987; Newman and association (Baylis, 1975). This fuzziness in root Reddell, 1987; Miller et al. 1999; Muthukumar et al. hairs in Carex spp. has been used by authors like 1996, 1997; Muthukumar and Udaiyan 2000). Reznicek (1986) for description and identification of Harley and Harley (1987) examined 54 species of species. Fungal hyphae and its relation with vesicle Cyperaceae, of which 31% had mycorrhizal formation were reported by Giovannetti and Sbrana infection. In a study in Southern India that sampled (1998), which occurs after arbuscular development. 24 species for six genera of Cyperaceae, all the These vesicles are considered as storage organs and plants sampled had some infection and 42% of them often functions as propagules (Biermann and had formed arbuscules (Muthukumar et al . 1996, Lindermann, 1983). Uptake of carbon from host cell 1997; Muthukumar and Udaiyan 2000). Miller et al . interface does prevail (Solaiman and Saito 1997; (1999) have also reported the presence of Douds et al. 2000), and hyphal network could be mycorrhizaae in Carex L. along with its simple involved in carbon transport (Robinson and Fitter, types. Hence, this variation in mycorrhizal 1999). Along with the presence of fungal mycelium, association as noted in sedges in general and the vesicles, arbuscular unidentified dark septate fungus genus Carex in particular may be environmental or was also reportd in several species of Carex from edaphic rather than phylogenetic constraint (Read et Artic and Alpine region (Jumpponen and Trappe, al. 1976; Muthukumar et al. 1996). It has also been 1998) and by Miller et al . (1999) from the shavanas. speculated that the non-mycorrhizal condition of Since 1987, studies and information have some sedges might result from their habitat been made available for 221 sedges species condition, anaerobic soil rather than taxonomic (including 78 species of Carex ; of which 27 position (Tester et al. 1987). But to complicate the mycorrhizal, 4 facultative mycorrhizal and 47 non- matters even more, the root of the sedges appear to mycorrhizal) of which 88(40%) are mycorrhizal be associated with several kinds of fungi or even 24(11%) are facultative and 109(49%) are non- dark septate hyphae (Haselwandter and Read, 1980; mycorrhizal (Muthukumar et al. 2004). Based on 1982; Bledsoe et al. 1990; Kohn and Stasovski, these studies, the genus Carex as well as the family 1990). The study of development and seasonal Cyperaceae is no longer a non-mycorrhizal, but the fluctuations in VAM associated plants have been mycorrhizal. Even, status is greatly influenced by carried out by Sanders and Fitter (1992), Louis and environmental conditions. Even more, Carex spp. Lim (1987), Brundrett (1991), and have concluded appear to have several morphological adaptations to that VAM development depends on edaphic factors, thrive in the absence of mycorrhizal associations. or variation in plant nutrient level (Mullen and Though mycorrhizal, associations have been noted in Schmidt 1993; Tester et al. 1987). Effects of many Carex species, the ecological role of this moisture and nutrient availability on root growth and association is not well documented. Similarly, the VAM colonization was reported by (Raab et al. beneficial role of mycorrhiza in Carex spp. and other 1999; Rabatin, 1979; Allen, 1983; Muthukumar et al. members of sedges are yet to be fully ascertained. 1997). As there is negative correlation between Hence, to verify, many reports on the mycorrhizal mycorrhizal association and soil moisture (Anderson association in Carex and since no report was found et al. 1984) the non mycorrhizal nature of sedges to have been reported from this region the study was may be due to their presence in marshy land, conducted and there is a comprehensive report of anaerobic soil rather than taxonomic position mycorrhizal association in Cyperaceae especially in (Haselwandter and Read, 1980; Kohn and Stasovski, the genus Carex . 1990). Production of swollen dauciform roots with long hairs when growing in nutrient deficient 2. MATERIALS AND METHODS condition was reported by (Davies et al. 1973; Lamont, 1974; Miller et al. 1999) which increases The plants worked out for mycorrhizal association under low nutrient condition (Fohse and Jungk, were collected from Darjeeling, Senchal, Rangbul, 1983; Fohse et al. 1991) and this presence of root Leebong, and Lava Bazar of the Darjeeling L - 2 Life Science Botany Research Article ISSN 2250-0480 VOL 4/ISSUE 1/JAN-MAR 2014 Himalayas. Same specimens were collected from intersections were observed for each sample and different location to see the variability among photographs were taken where any kind of presence mycorrhizal association. The roots of 28 populations was noted. Notes were specially taking account of for 12 species of Carex, Cyperaceae were sampled in the presence or absence of same type or different between August, 2006 and November, 2010. From type of mycorrhizal associations in the same species the study site plant specimen were collected along or in a different species, or even the different with the roots and the rhizosphere. (Details of the individual of same species. collection information presented in Table 1). Rhizospheric soil was collected for each sample by 2.1. ESTIMATION OF AVAILABLE shaking the soil loose from the roots, as they were PHOSPHORUS FROM THE SOIL collected. This assured that the soil of collected plant materials were packed in a polythene bag along with Since the availability of phosphorus is inversely roots and soils from the study site itself. Upon return related with the presence of mycorrhizal association to the work place, the core attached with plant shoot (Allen et al. 1987; Muthukumar and Udaiyan, 2000; was placed in a large polythene bag and refrigerated Raab et al. 1999; Rickerl et al. 1994); test for at 0°C to 4°C. Within 3 days of sampling, the soil estimation of total phosphorus (Table 2) was carried was excavated and the root portion was washed out out with every soil sample collected from the until most of the mud particles were rinsed (after rhizosphere of all the populations studied to find out Miller et al. 1999). To assure that roots of correlation if any present between the phosphorus appropriate individuals were sampled, rhizomes and availability and mycorrhizal association. The stolons, attached to the main root were excavated. phosphorus present was ascertained through Young and newly formed roots were selected and modified methods of Mazumdar and Majumder carefully collected. This could be easily (2003). distinguished by their pale brown to brown coloration, against the dark brown to black colors of 3. OBSERVATION AND old and dead roots (Muthukumar et al. 1999). Only DISCUSSION fibrous roots attached to the crown of the Carex were retained.