Track 4-1-1: Plant Genetic Resources, Collection, Conversation, Evaluation and IPR Issues

Description

Rangelands are colonized vast natural landscapes in the form of grasslands. These are mostly dominated by native grass species. Once a patch is colonized by a pioneer species, complex interactions may develop among plants of different species. The frequency of positive interactions has been shown to be high in harsh environments, particular in arid environments, where it has been identified as a driving mechanism of vegetation dynamics (Bruno et al., 2003). These processes commonly involve nurse plants (Niering et al., 1963) that facilitate the establishment of other plants species beneath their canopies (Franco and Nobel, 1988). Based on this principle we hypothesized that Panicum turgidum, Forssk., may act as a potential nurse plant for a number of other plant species in the Thar Desert. In this region, this plant is one of the main component of vegetation patches surrounded by a bare soil matrix, in association with a restricted number of other species. Our objective was to characterize the positive associations of P. turgidum with Caralluma edulis in the Thar Desert. The Thar Desert is characterized by high velocity wind, huge shifting and rolling sand dunes; high diurnal variation of temperature; scarce rainfall; intense solar radiation and high rate of evaporation. Thar Desert receives between 100 to 500 mm of rainfall every year, 90% of which is received between July and September. The sandy soils of the desert have a rapid infiltration rate of water, poor fertility, low humus content due to rapid oxidation and high salinity. Though, all conditions are very hostile for the existence of life, some grasses like Lasiurus sindicus, Panicum turgidum, Dichanthium annulatum, Ochthochloa compressa (syn. Eleusine compressa), Cenchrus ciliaris and Cenchrus setigerus perform well in desert. Among these grasses Panicum turgidum is major component of vegetation on sand dunes.

Worldwide, the distribution of P. turgidum extends in the Sahara from Mauritania across North Africa with extensions into the Sahel, and through the Arabian Peninsula to Pakistan and India (Poilecot, 1999). It is a perennial Saharan species of family Poaceae, growing as dense tussocks up to 1.5m in height, and creating dense hillocks up to 0.4m high. P. turgidum is highly resistant to water stress, and is a major component of the vegetation of the inter-mountain zones of the Thar (Poilecot, 1996). The seeds serve as a grain substitute in the diet of the Tuareg inhabitants and the straw as fodder for livestock and as roofing material. P. turgidum is also a component of the diet of wild animals of high conservation value such as Addax nasomaculatus, Blainville, Oryx dammah, Cretzschmar and Struthio camelus, L. (Poilecot, 1999).

P. turgidum has the merit of being resistant to drought and also an effective sand-binding xerophyte. Wind-borne sand usually accumulates around the bushes of P. turgidum forming isolated mounds that gradually enlarge and eventually coalesce and form sandy patches.

Share

COinS
 

Role of Panicum turgidum Dominated Rangelands in Conservation of Caralluma edulis in Thar Desert, India

Rangelands are colonized vast natural landscapes in the form of grasslands. These are mostly dominated by native grass species. Once a patch is colonized by a pioneer species, complex interactions may develop among plants of different species. The frequency of positive interactions has been shown to be high in harsh environments, particular in arid environments, where it has been identified as a driving mechanism of vegetation dynamics (Bruno et al., 2003). These processes commonly involve nurse plants (Niering et al., 1963) that facilitate the establishment of other plants species beneath their canopies (Franco and Nobel, 1988). Based on this principle we hypothesized that Panicum turgidum, Forssk., may act as a potential nurse plant for a number of other plant species in the Thar Desert. In this region, this plant is one of the main component of vegetation patches surrounded by a bare soil matrix, in association with a restricted number of other species. Our objective was to characterize the positive associations of P. turgidum with Caralluma edulis in the Thar Desert. The Thar Desert is characterized by high velocity wind, huge shifting and rolling sand dunes; high diurnal variation of temperature; scarce rainfall; intense solar radiation and high rate of evaporation. Thar Desert receives between 100 to 500 mm of rainfall every year, 90% of which is received between July and September. The sandy soils of the desert have a rapid infiltration rate of water, poor fertility, low humus content due to rapid oxidation and high salinity. Though, all conditions are very hostile for the existence of life, some grasses like Lasiurus sindicus, Panicum turgidum, Dichanthium annulatum, Ochthochloa compressa (syn. Eleusine compressa), Cenchrus ciliaris and Cenchrus setigerus perform well in desert. Among these grasses Panicum turgidum is major component of vegetation on sand dunes.

Worldwide, the distribution of P. turgidum extends in the Sahara from Mauritania across North Africa with extensions into the Sahel, and through the Arabian Peninsula to Pakistan and India (Poilecot, 1999). It is a perennial Saharan species of family Poaceae, growing as dense tussocks up to 1.5m in height, and creating dense hillocks up to 0.4m high. P. turgidum is highly resistant to water stress, and is a major component of the vegetation of the inter-mountain zones of the Thar (Poilecot, 1996). The seeds serve as a grain substitute in the diet of the Tuareg inhabitants and the straw as fodder for livestock and as roofing material. P. turgidum is also a component of the diet of wild animals of high conservation value such as Addax nasomaculatus, Blainville, Oryx dammah, Cretzschmar and Struthio camelus, L. (Poilecot, 1999).

P. turgidum has the merit of being resistant to drought and also an effective sand-binding xerophyte. Wind-borne sand usually accumulates around the bushes of P. turgidum forming isolated mounds that gradually enlarge and eventually coalesce and form sandy patches.