To study the phytoremedial potential of some chenopods
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Date
2005
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CCSHAU
Abstract
The effects of different levels of salinity on growth, development, water content
and ion accumulation in the six chenopods (Suaeda fruticosa, Salicornia brachiata,
Atriplex nummularia, Atriplex lentiformis) and glycophytes (Chenopodium murale,
Spinacea oleracea) were determined. These chenopods were grown in pots at 0, 8, 12, 16
and 20 dSm-1 levels of salinity and plants were harvested at their maximum vegetative
growth (Salicornia brachiata and Spinacea oleracea) or at flower initiation stage (Suaeda
fruticosa, Atriplex nummularia, Atriplex lentiformis and Chenopodium murale). Increase
in salinity stimulated plant height, number of branches and leaves per plant, fresh/dry
weight of stem and leaves in halophytic species. But these parameters were adversely
affected in Spinacea oleracea and Chenopodium murale. Water contributed to a large
proportion towards increase in fresh biomass of halophytes. The accumulation of ions
was greater in leaves than in stem. The contents of Na+ and Cl- in both stem and leaves of
all chenopods increased with every increment in salinity. Elevated salinity induced
decrease in Ca2+, K+, Mg2+ and SO4
2- in all chenopods. Suaeda fruticosa accumulated a
large quantity of ions in comparison to other chenopods as well. Higher salt tolerance in
Suaeda fruticosa, Atriplex nummularia and Atriplex lentiformis could be ascribed to their
ability for osmoregulation and effective compartmentation of ions.
Another interesting observation was higher magnitude of total ionic contents in
the harvestable biomass of different chenopods like Suaeda fruticosa, Salicornia
brachiata, Atriplex nummularia and Atriplex lentiformis and concomitantly retention of
less amount of ionic content in the soil after harvesting of the above chenopods.
Conversely, the magnitude of total ionic content in the harvestable biomass of
Chenopodium murale and Spinacea oleracea was less and consequently the total ionic
contents in the soil of the above mentioned chenopods was observed more.
Likewise ECe and pH of the soil on comparison before transplantation of the
different chenopods in the soil and after harvesting of chenopods indicated that these
were reduced at all salinity levels and the reduction was more in Suaeda fruticosa,
Salicornia brachiata, Atriplex nummularia and Atriplex lentiformis and it was least of all
in case of Chenopodium murale and Spinacea oleracea.
The computed data on per cent remediation in terms of total estimated ionic
accumulation in the harvestable biomass in the chenopodsin comparison to total
estimated ionic accumulation in the soil at various added salinity levels, explicitly
showed that, although, it decreased with increase in salinity levels. Nevertheless, Suaeda
fruticosa, Atriplex nummularia and Atriplex lentiformis were able to remediate 3.99, 3.74,
3.46 and 2.90 per cent soil salinity at 20 dSm-1 , respectively. Likewise, the figures on per
cent remediation at 8, 12, 16 dSm-1 were still higher than at 20 dSm-1. It was worth
mentioning that Suaeda fruticosa followed by Atriplex nummularia, Atriplex lentiformis
and Salicornia brachiata were able to remediate the soil salinity more than Chenopodium
murale and Spinacea oleracea.
Nevertheless, further extensive studies are needed with several other native flora
and indigenous halophytic taxa to find out their relative long-term (3-4 years) efficacy to
extract salts from the saline soil to develop a plant based sustainable remediation
technology for greening of saline wastelands in India.