Morpho-physiological study of Calendula officinalis L.under saline conditions
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Date
2013
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CCSHAU
Abstract
Calendula officinalis L. commonly known as pot marigold in English belongs to the family Asteraceae (Compositae). It is an important medicinal herb indigenous to central, eastern and southern Europe. It is cultivated commonly in North America, Eastern Europe, Germany and India for medicinal as well as ornamental purpose. The present investigation was undertaken to enrich the scientific database regarding the morpho-physiology of Calendula officinalis under non-saline field and saline conditions.
Two experiments were planned. First experiment was performed to study the phenology, growth and reproductive behavior of Calendula officinalis under natural non-saline field conditions. Seeds were sown in the first week of December. Phenological study depict the vegetative growth up to March. Flowering (anthesis) initiated simultaneously in the month of February and continued till mid April. Fruiting and seed maturation also occurred simultaneously from mid April to early May. Death / senescence was observed from early May onwards.
The overall growth of Calendula officinalis L. under field conditions was better than under pot conditions. All plant growth attributes viz., plant height (cm), basal stem diameter (mm), number of leaves plant-1, leaf biomass (g plant-1), stem and branches biomass (g plant-1), flowers and fruits biomass (g plant-1) and root biomass (g plant-1) studied in the present experiment were found to increase with the advancement of growth stage under field conditions. The root/ shoot ratio, however, decreased with the advancement of growth stage.
The reproductive performance of Calendula officinalis L. in general, was better under field conditions as compared to pot culture. Reproductive behaviour was studied in terms of the number of flower heads plant-1, number of seeds head-1, seeds output (number plant-1), seed yield (g plant-1), germination of seeds produced and reproductive capacity in field conditions.
The second experiment was performed to study the morpho-physiological attributed of Calendula officinalis under chloride dominated salinity. The plants were raised in sand filled polythene bags under varying EC levels viz., 0 (control), 4, 8 and 12 dSm-1 of nutrients supplemented chloride dominated salinity. Progressive increase of EC level from 0 to 12 dSm-1 caused a significant decline in growth parameters viz., plant height (cm), number of leaves plant-1, leaf biomass (g plant-1), stem and branches biomass (g plant-1), flowers and fruits biomass (g plant-1), root biomass (g plant-1) and root / shoot ratio. However, these parameters increased significantly with the advancement of growth stage (GS).
Reproductive attributes such as number of flower heads plant-1, number of seeds head-1, seed output (number plant-1), seed yield (g plant-1), geminability of seeds produced and reproductive capacity suffered a reduction with the rise of salinity. Both days to flower initiation and days to maturity were increased with the progressive increase of EC level in the growth medium.
Physiological parameters viz., chlorophyll -a (mg g-1 dw), chlorophyll -b (mg g-1 dw) and total chlorophyll content (mg g-1 dw) of leaves and carotenoid content (mg g-1 fw) of flower petals significantly decreased with the increase of salinity in the growing medium. Accumulation of proline (mg g-1 dw) and increase in relative stress injury (%) in the leaves was observed with the progressive increase of salinity.
Enhancement of sodium and concomitant decline of the potassium content (mg g-1 dw) in leaves was found with the rise of EC level in growing medium. Accumulation of both chloride and sulphate was observed with the increase of salinity. The accumulation of chloride was relatively less in leaves at the maturity stage than sulphate.
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Keywords
Calendula officinalis, Pot marigold, Salinity, Growth, Yield parameters, Reproductive capacity, Chlorophyll, Carotenoids, Proline, RSI, Sodium, Potassium, Chloride, Sulphate