Comparative Study of treated and untreated wastewater on morpho-anatomical, chemical and essential oil contents of fragrant Rosa species in peri-urban area

Abstract

The work was carried out to assess the effects of treated and untreated wastewater on morpho-anatomical, physio-chemical and essential oil contents of four widely cultivated fragrant Rosa species of Pakistan during 2012 and 2013 in peri-urban area. Water analysis showed that all minerals and chemicals were in permissible level in canal water and treated wastewater whereas, untreated water contained higher EC, BOD, COD and heavy metals like Cd, Co, Cu, Pb. Morphological studies showed that treated wastewater has a pronounced effect on floral attributes of Rosa species. Rosa Gruss-an-Teplitz produced the maximum number of flowers per plant, increased bud and flower diameter, number of petals per flower and took minimum days to produce flowers. Whereas, plant height and number of leaves per branch was high in R. bourboniana and leaf area was found maximum in R. damascena. Anatomical study showed that R. Gruss-an-Teplitz showed remarkable variations in root anatomical characteristics under treated wastewater. A significant variation was recorded in R. Gruss-an-Teplitz in terms of large cortical cell area, large vascular bundle area, large xylem and phloem area, large pith area and large cross sectional area while thick epidermis and large metaxylem area was recorded in R. bourboniana. Stem anatomical characteristics showed that large cortical cell area was recorded in R. damascena under untreated wastewater treatment and R. Gruss-an-Teplitz showed thick epidermis and large xylem area in untreated and treated wastewater respectively whereas R. bourboniana showed large pith area in treated wastewater. Rosa Gruss-an-Teplitz showed significant variations in leaf characteristics under treated and untreated wastewater treatment such as, large cortical cell area, vascular bundle area, large spongy cell area and thicker midrib whereas a remarkable increase in epidermal thickness was recorded in R. centifolia. Large palisade cell area, large phloem area and thick leaves (lamina) were found in R. damascena in treated wastewater. Physiological attributes revealed that in treated wastewater, high photosynthetic rate, transpiration rate and chlorophyll content of R. bourboniana was recorded and stomatal conductance was high of R. Gruss-an-Teplitz. Minerals and other chemicals concentration of all plant parts were highest under untreated wastewater. Higher nitrogen contents were found in roots of R. bourboniana; R. centifolia’s roots contained maximum Ca, Na, Zn, Cu, Cr, Ni and Co concentration while roots of R. damascena retained maximum K and Pb level whereas, P and Fe contents were highest in roots of R. Gruss-an-Teplitz. In stems, N, K and xv Fe contents were higher in R. Gruss-an-Teplitz, Na level was maximum in R. bourboniana. P, Ca, Cu and Cr contents were highest in R. centifolia whereas, Zn, Pb, Cr, Ni and Co contents were high in stems of R. damascena. In leaves, N and Na level was high in R. bourboniana while P, Ca, Fe, Zn and Ni contents were highest in R. Gruss-an-Teplitz. K and Pb level was high in leaves of R. damascena whereas Cu, Cr and Co contents were high in R. centifolia. In flowers, R. bourboniana contained high concentration of N and Na while P, Cu and Co contents were high in R. centifolia. Calcium and Zn level was at the top in leaves of R. Gruss-an-Teplitz whereas K, Fe, Pb, Cr and Ni contents were high in flowers R. damascena. Lead was the only chemical whose concentration was high in flowers of R. centifolia and R. damascena under untreated wastewater than the maximum recommended values set by WHO while other minerals and chemical levels were in permissible limit. Out of 12 essential oil components found in this study, citronellol which is the principal constituent for fragrance was highest in essential oil of R. damascena under untreated wastewater while its percentage was lowest in R. Gruss-an-Teplitz. Phenyl ethyl alcohol was main component of essential oil and its percentage was highest in R. Gruss-an-Teplitz under treated wastewater and minimum level was found in R. damascena. The other components of essential oil of all Rosa species were found in traces under all irrigation water treatments. Although statistically no significant effect of irrigation water treatments on oil components was observed however, there was quantitative difference in chemical composition and aroma constituents of essential oil of all fragrant Rosa species. From the results of present studies, it can be concluded that R. Gruss-an-Teplitz showed high degree of tolerance against contaminated water and is strongly recommended to cultivate in peri-urban areas. Moreover, treated wastewater can serves as an alternative source of canal water after management of toxic elements to save water and environment.