STUDIES ON THE HOST RANGES OF ANGIOSPERM PARASITES Dendrophphoe falcata var. coccinia AND Cassytha filiformis IN ANNAMALAI RESERVE FOREST, THIRUNANNAMALAI, TAMIL NADU, INDIA

M. Pandian 1 , S. Natarajan 2 and A. Stephen 3 . 1. Research Scholar, Department of Plant Biology and Biotechnology, Guru Nanak College, Velachery, Chennai42, Tamil Nadu, India. 2. Associate Professor, Department of Plant Biology and Biotechnology, Guru Nanak College, Velachery, Chennai-42, Tamil Nadu, India. 3. Assistant Professor, School of Liberal Arts and Sciences, Trans-Disciplinary University, Bengaluru, India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

This study pertains to the evaluation of host ranges of angiosperm parasites Dendrophthoe falcata (L.f.) Ettingsh var. coccinia (Talb.) Sant. (Loranthaceae) and Cassytha filiformis L. (Lauraceae) on various angiosperm host plants in the Annamalai reserve forest, Thiruvannamalai District, Tamil Nadu, India. D. falcata was found growing on five host trees belonging to four families of Dicotyledons in a localised area of the hill but C. filiformis had a wide range of 26 host plants belonging to 18 families of Dicotyledons which grew from the plains to thehill top. Study revealed that C. filiformis had managed to increase its host ranges rather than D. falcata. Polymorphism of leaves were also observed in D. falcata. Instances of double parasitism were found on Acacia chundra and Diospyros ferrea.
Cassytha filiformis is a leafless, vine-like, climbing and hemi-parasite which parasitizes on a wide variety of woody hosts including plants of agricultural, horticultural and economic values. The host ranges of C. filiformis is broad ISSN: 2320-5407 Int. J. Adv. Res. 5(9), 1045-1050 1046 (Nickrent and Musselman, 2004). Nelson (2008) had stated that the parasite obtains nutrients and water from the host plants without quickly killing the host cells. The pathogen does not create immediate fatal damages to the host cells and their metabolic processes. Rather the host plants can die a long protracted death by starvation and desiccation. Heavy infections can eventually smoother and kill host plants. Cassytha filiformis is reported to be capable of transmitting phytoplasma from palms (Cocos nucifera L. and Areca catechu L.) and a viral disease such as citrus mosaic caused by citrus mosaic badna virus (Nelson, 2008). It is a common stem parasite of Lantana camera L. and Toddalia sp and certain other plants in south India (Rangaswamy and Rangan, 1963). Werth et al. (1979) had listed out 81 species which were affected by C. filiformis in the Bahamar, including grasses, ferns, gymnosperms as well as board-leaved angiosperms. Cassytha filiformis has a wide host ranges such as grasses, broad leaved angiosperms, ferns and gymnosperm (Mukhtar et al. 2010; Kokubugata and Yokota, 2012). In this parasite fruits are dispersed by birds (David et al., 2015). Balasubramanian (1990) noted that seeds were taken by white-browed bulbul (Pycnonotus luteolus). Following germination, the primary root fails to develop but adventitious roots may provide anchorage for a short period (Mahadevan and Jayasuriya, 2013). Seedlings can then survive up to eight weeks, without a host, growing to a length of 30 cm or more relying on the seed reserves (Nelson, 2008).

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We visited the study area between January 2016 and January 2017 covering all the four seasons. We laid 20 quadrats each measuring 10x10m and ensured a distance of 100 meters between two quadrats. We identified angiosperm parasites D. falcata and C. filiformis and enumerated and identified host plants in each quadrat to assess the host ranges of these two parasites. All the host plants were identified using "The Flora of Presidency of Madras" (Gamble and Fischer, 1959), "The Flora of Tamil Nadu Carnatic" (Mathew, 1983) "Flora of Tamil Nadu" (Nair, N. C. and Henry,

Results and Discussion:-
Dendrophthoe falcata produces tubular, bisexual and red coloured flowers arranged in spikes. Pollination is entomophilous because the red coloured perianth and nectar attracts insects. The seeds are carried and dispersed by sunbirds Cinnyris asiatica (Passeriformes: Nectariniidae)). Our study revealed that the parasite D. falcata was found growing on five host trees belonging to four families in undisturbed areas of the hill. The leaves of D. falcata exhibited polymorphism on different host plants. The shape and size of leaf lamina varies depending on the host plants on which it grows. (Fig 2 a, b & c). The leaf areas of this parasite on various host trees were calculated using Kemp"s formula. The maximum leaf area (53.85 cm 2 ) was found in Azadirachta indica followed by Cassia fistula (25.74 cm 2 ), Acacia chundra (6.86 cm 2 ), Flacourtia ramontchi (6.45 cm 2 ) and Acacia leucophloea (5.77 cm 2 ). falcata had infested five tree species belonging to four families, found in the undisturbed reserve forest and was absent in other parts of the human impacted forest, even though the host trees were found predominant (Table 1). It is observed that frequent movement of the general public and pilgrims to ashrams situated in the foot hills daily, particularly during festive seasons in the eastern, north-eastern and south-eastern sides of the hills, prevents the visit of sunbirds which were found active in dispersal of seeds from the fruits of D. falcata. The parasite, hence was found only in the undisturbed forest where sunbirds visit frequently. Visits of such birds on the parasite and consumption of its fruits were noticed during morning (06.00-10.00 hrs) and evening (15.00-17.30 hrs) in the undisturbed forest. This attributes that sunbirds were active in dispersal of the seeds in the undisturbed forests and hence D. falcata had confined its host ranges in a localised area and did not extend beyond five species. It had not infested any host plants belonging to Monocotyledons.
In C. filiformis also the fruits are dispersed by birds (David et al., 2015). Balasubramanian (1990) noted that seeds were taken by white-browed bulbul Pycnonotus luteolus (Passeriformes: Pycnonotidae). Following germination, the primary root fails to develop but adventitious roots may provide anchorage for a short period (Mahadevan and Jayasuriya, 2013). Seedlings can then survive up to eight weeks, without a host, growing upto a length of 30 cm or more relying on the seed reserves (Nelson, 2008). Study revealed that C. filiformis was found infested on 26 hosts plants in the study area belonging to 18 families. Twenty-four plants are indigenous, one is exotic and another one is cosmopolitan. When compared to D. falcata, the parasite C. filiformis had exhibited a wide host ranges in the Annamalai reserve forest. It affects the host plants with various habits such as trees, shrubs, sub-shrubs, herbs and climbers (Fig 2 d, e, f & g). Out of 26 hosts infested by C. filiformis, 11 are trees, 12 are shrubs, 2 are climbers and one is a herb. Infestation of hosts by C. filiformis were found in all parts of the forests ranging from altitudes 200 m to 730 m above mean sea level (Table 2). Seeds of C. filiformis were easily dispersed by white-browed bulbuls which were observed commonly at all parts of the study area and characteristic features such as survival of seedlings for even eight weeks without host substratum, ability to grow on soil independently and later become obligate parasite when it comes into contact with host plants might have helped this parasite to extend its host ranges. Whereas D. falcata which required sunbirds for dispersal of seeds and seedlings need immediate host substratum for successful survival might have resulted in failure of extending its host ranges beyond five trees. These two parasites never infest any of the host plants belonging to Monocotyledons. Though the angiosperm parasites were part of bio-diversity of the forest vegetation, its impact on the forest vegetation, transmission of diseases and economic loss to the woods of trees need further study.
Selvi and Kadamban (2009) had reported instances of double parasitism of these two parasites on host plants, viz., Anacardium occidentale L. and Azadirachta indica L at Pondicherry Engineering College campus. Similar instances of double parasitism were found in the case of two indigenous species namely, Acacia chundra (Rottler.) Willd. and Diospyros ferrea (Willd.) Bakh. in the study area. Both D. falcata and C. filiformis had infested and grew extensively on these two host trees.

Conclusion:-
The parasite D. falcata had so far not extended its host ranges in the forest, beyond 5 host trees belonging to four families, but C. filiformis had extended its host ranges up to 26 host species belonging to 18 families. D. falcata was confined in the undisturbed western side of the Annamalai reserve forest, but C. filiformis had widened its habitats from plains to an altitude of 814m AMSL. It depends on the host trees and the morphology of leaves (polymorphism) vary in D. falcata. Double parasitism was observed on two indigenous trees such as Acacia