Effect of salt stress on the structure and carbon flow mechanism in a noxious weed Parthenium hysterophorus L.

Abstract

Summary Effect of salt stress on structural changes, ion uptake, rate of photosynthesis and path of carbon in the exotic weed Parthenium hysterophorus have been investigated. Photosynthetic leaf area, chlorophyll and carbon assimilation rates were adversely affected by salt stress. Increased Na+ uptake caused decrease in K+ and Ca2+ absorption. Originally a C3 plant, P. hysterophorus appears to form aspartate as a primary product of photosynthesis when exposed to NaCl. The stimulation of PEP carboxylase activity also occurred due to salt stress. Excessive accumulation of malate during steady state of photosynthesis was possibly due to inhibition of malic enzyme. It appears that although the plant switches over to an ‘aspartate producer’ when exposed to salt, further utilization of photosynthetically assimilated carbon is through malate. Being a weed, the plant appears to be highly adaptive to stress conditions.

Soil Degradation of Parthenin—Does it Contradict the Role of Allelopathy in the Invasive Weed Parthenium hysterophorus L.?

“…It aggressively colonizes areas, often to the total exclusion of indigenous plant species. Characteristics that make the weed such an effective invader include tolerance of a wide range of ecological and climatic conditions, a fast growth rate, high fecundity, and efficient utilization of resources (Hedge and Patil 1982;Parsons and Cuthbertson 1992). Furthermore, it is hypothesized that P. hysterophorus is able to impede the recruitment and/or growth of naturally occurring plant species by means of allelopathy.…”

Variation of Parthenium hysterophorus in response to soil quality: implications for invasiveness

“…According to McFadyen, 1992), the weed is an aggressive colonizer of disturbed lands in Australia and has spread rapidly from the point of introduction to an area of more than 170 000 km 2 . P. hysterophorus has a wide range of ecological adaptation (Hegde & Patil, 1982), and the rapid growth of this weed species in diverse ecological conditions has been attributed to its strong reproductive potential (Kohli & Rani, 1994), the ability for rapid germination and its allelopathic properties inhibiting the germination and growth of other associated plant species (Mersie & Singh, 1987; Adkins & Sowerby, 1996). The water‐soluble allelochemicals are involved in allelopathic responses (Picman & Picman, 1984) and induce severe allergic dermatitis and other symptoms such as allergic rhinitis and bronchitis (McFadyen, 1995; Evans, 1997).…”

Effects of some integrated management options on parthenium interference in sorghum

“…2005). Its wider adaptability, photo‐ and thermo‐insensitivity, drought‐ and salt‐tolerance (Hegde & Patil 1982), little or no seed dormancy (Navie et al . 1998), good competitive and allelopathic ability (Kanchan & Jayachandran 1979; Adkins & Sowerby 1996), low photorespiration under arid conditions (Rajendrudu & Das 1981), and huge production of small and light seed (15 000–25 000 seeds or achenes per plant) (Joshi 1991) have contributed to its rapid spread in the tropics.…”

“…Parthenium (Parthenium hysterophorus L.; family Asteraceae; tribe Heliantheae; subtribe Ambrosiinae) is an exotic weed, but has become fully naturalized in uncropped areas of Africa, Asia, and Australia (Navie et al 1996;Mahadevappa 1999;Tamado & Milberg 2004;Besufekad et al 2005). Its wider adaptability, photo-and thermoinsensitivity, drought-and salt-tolerance (Hegde & Patil 1982), little or no seed dormancy (Navie et al 1998), good competitive and allelopathic ability (Kanchan & Jayachandran 1979;Adkins & Sowerby 1996), low photorespiration under arid conditions (Rajendrudu & Das 1981), and huge production of small and light seed (15 000-25 000 seeds or achenes per plant) (Joshi 1991) have contributed to its rapid spread in the tropics.…”