Emad Farahat | Helwan University (original) (raw)

Papers by Emad Farahat

Studies on plant population demography and size structure provide important base for monitoring a... more Studies on plant population demography and size structure provide important base for monitoring and managing plant species. The present study investigated the monthly variation in plant demography, population dynamics and size structure of Calotropis procera in urban areas, South Cairo, Egypt. Sixty-three permanent quadrats were selected to represent the monthly variation in the characteristics of C. procera population all over one year. The highest plant density was attained in June and the lowest in February and March. The highest biomass was recorded in November, but the lowest in March. The maximum individual's height was recorded from August to January, while the minimum was in late winter. The monthly size distribution indicated that C. procera had three different size distributions along the whole year: more or less inverse J-shape, positively skewed and bimodal size distribution. The maximum plant survival was correlated with the availability of soil moisture. The demographic flux indicated that the new branches of plant were mainly formed during April and June, followed by significant mortality in July and October. This study may contribute in planning for managing and conserving this medicinal plant.

The present study was conducted to evaluate the potentiality of the aquatic macrophyte Pistia str... more The present study was conducted to evaluate the potentiality of the aquatic macrophyte Pistia stratiotes to accumulate trace metals, perspective of phytoremediation, and the probability for using it as a bioindicator for the different pollution types. Plants were collected from the different Lake Mariut basins (main basin, southwest , northwest , and fish farm), through five quadrats each, for measuring some growth parameters such as plant density, rosette diameter and height, root length, number of living and dead leaves per individual , and leaf length and width. In addition, nutrients and heavy metals in plant organs as well as water samples were analyzed. The bioaccumulation and trans-location factors of trace metals were calculated. Water physicochemical data of Lake Mariut showed significant variations of all variables, except temperature and pH as well as Cd metal, among the lake basins. Fish farm was characterized by the highest plant density, individual size, biomass, and the number of living leaves, while the northwest basin had the lowest, except the number of dead leaves. In contrast to trace metals, P. stratiotes accumulated concentrations of macronutri-ents in the leaves higher than in roots. The bioaccumu-lation factors of the investigated metals, except Cu, were greater than one, while the translocation factors (TFs) of all trace metals were less than unity, and this may render P. stratiotes suitable for rhizofiltration. In addition, the significant positive correlation of Ni and Cd in water with those in plant roots and leaves as well as the growth response of this plant to the different pollutants may suggest its potential use as bioindicator for these pollutants in water.

We investigated the effects of dust deposition on the radial growth and sensitivity to climate of... more We investigated the effects of dust deposition
on the radial growth and sensitivity to climate of eastern
hemlock [Tsuga canadensis (L.) Carrie`re] growing near its
northern range limit in southern Quebec, Canada. We
constructed a ring-width chronology from 1867 to 2007 for
hemlock trees growing in an old-growth forest adjacent to a
rock quarry. Significant decline in the radial growth of
hemlock occurred after construction of the quarry in 1959,
with a mean decrease of 42.7 % compared to previous
growth rates and with major changes occurring 3–16 years
after the quarry establishment. Moreover, the growth–climate
relationships changed from a predominant response to
temperature and precipitation during the growing season
before the quarry establishment, to weaker precipitation
sensitivity and a stronger association with summer temperatures
in year prior to growth. Our results indicate that
the main response of the hemlock trees to dust deposition is
reduced growth rates, but the change in growth–climate
relationships can also be related to this environmental
stress.

The present study was conducted to evaluate the accumulation potential of Calotropis procera for ... more The present study was conducted to evaluate
the accumulation potential of Calotropis procera for
nutrients and heavy metals and its impact on the forage
quality of such medicinal plant. Three plant individuals of
C. procera as well as three composite soil samples, collected
from four urban habitats (residential areas, road
sides, railways, and fallow lands) were analyzed for
nutrients and heavy metals. It was indicated that all soil
heavy metals, except Cd and Pb in railways, were in the
safe range. The plant leaves from residential areas contributed
to the highest concentrations of total N, P, Na, and
Mg, in addition to ash content, crude protein, and crude
fibers, while those from railway habitat had the highest
values of digestible, metabolized, net, and gross energy. On
the average, all investigated metals had bioaccumulation
factor (BF) more than unity with the highest value recorded
for Cd. Moreover, the order of uptake capability of heavy
metal was in the order Cd[Fe[Mn[Zn[Cu[Pb.
C. procera had a good forage quality, but it could not be
used as animal forage in polluted areas, since it can
accumulate high concentrations of heavy metals in toxic
levels. The high BF of this species to Mn and its significant
positive correlation with its soil content renders this species
suitable as a good bioindicator and biomonitor for this
heavy metal.

Phenology is a major trait structuring life history strategies and its role in shaping plant inva... more Phenology is a major trait structuring life history
strategies and its role in shaping plant invasions that
has increasing attention. The present study aimed to
examine the role of phenology, reproductive, and morphological
attributes of Calotropis procera in colonizing
urban areas, besides assessing its biomass and developing
allometric regression equation for prediction of its biomass.
Sixty-three permanent quadrats were selected to represent
the distribution of C. procera in urban habitats at South
Cairo Province, Egypt. The present study revealed significant
positive correlation between fruiting phase of the
species and temperature, as well as the vegetative phase
and precipitation. C. procera is characterized by continuous
flowering for 8 months, with a peak in April and May,
which help in reproductive success of the species. It had its
highest biomass in November (439 kg ha-1), but the lowest
in March (343 kg ha-1), with an annual mean of 388 kg
ha-1. The linear regression based on plant volume as an
independent variable was found to be the best fit for biomass
prediction, with the highest coefficient of determination
(R2 = 0.81). The above-ground biomass of this
plant encourages its potential use as a renewable energy
source. Our study suggests that C. procera has efficient
plastic phenological and functional attributes that may
enable it to dominate many ecosystems in the future.
Efficient management plans are needed to mitigate the risk
of this plant on other ecosystems and conserve other native
species.

Little is known about the impacts of recycled wastewater irrigation on adult tree species, especi... more Little is known about the impacts of recycled wastewater irrigation on adult tree species, especially the nutrient resorption efficiency (RE) and proficiency (RP) during leaf senescence and whether trace metals are resorbed or not during this process. Here, we present a study on the concentrations of nutrients and trace metals in green and senesced leaves, collected from Eucalyptus camaldulensis and Casuarina spp., in four planted forests irrigated by wastewater (or groundwater as control). Stoichiometric ratios (C:N, C:P, and N:P), RE and RP from senesced leaves of the trees were investigated. The concentrations of trace metals showed normal levels and were below phytotoxic concentrations in green and senesced leaves except for Mn. The intra-specific variations in nutrient concentrations in senesced leaves showed larger differences among the sites than those found in green leaves. The studied tree species excluded excess elements by decreasing its proficiency. The RE for N and P was high under poor soil nutrient conditions, but very low under high availability of nutrients. Resorption of trace metals from senesced leaves was low and presented negative mean values for most metals at all sites. RP values were low or equal to zero for the estimated elements. C:N and C:P ratios were high at low nutrient availability i.e. control site, while N:P ratios were non-significant among sites in green or senesced leaves. Our results illustrate that forest trees have highly variable nutrient resorption capacities that vary under high nutrients availability and indicate that under continuous wastewater irrigation, low or negative resorption efficiency for trace metals and other nutrients is an efficient protective strategy.

Calotropis procera (giant milkweed) is a hardy xerophytic plant, which is distributed globally in... more Calotropis procera (giant milkweed) is a hardy xerophytic plant, which is distributed globally in many countries and has important economic and ecological functions. The present study aimed at estimating the effect of temperature, salinity and time of fruit dehiscence on the seed germination and seedling morphology of giant milkweed in urban habitats. Seeds were collected early (in June) and late (in December) from pre-dehiscent (EPRD, LPRD) and post-dehiscent (EPOD, LPOD) fruits. Mature seeds were 100% viable, while premature seeds did not germinate. The highest germination and mean time to germination was attained in full dark followed by dark/light, while no germination occurred at complete light. A significant difference between seeds from pre-and post-dehiscent fruits was assessed, while no significant difference between early and late seeds. Maximum germination was at 25 and 30°C, while germination was inhibited at 35°C, which demonstrates that temperature is one of the critical factors for giant milkweed seed germination. Moreover, salinity more than 2000 mg l-1 NaCl inhibited seed germination. It is likely that high temperature, direct light conditions and high salinity are the limiting factors for the establishment of giant milkweed seeds. The germination of C. procera seeds was significantly affected when germinated with Trigonella foenum-vulgare with the reduction of germination from 100 to 34%, while the later plant was not affected. C. procera is considered as an important medicinal plant; therefore, our results provide useful information for its management under different environmental conditions.

Microhabitat heterogeneity with a high environmental variability affects the persistence of speci... more Microhabitat heterogeneity with a high environmental
variability affects the persistence of species and
their population dynamics. This study investigated the effect
of urban habitat heterogeneity on the morphological
and reproductive traits as well as foliar nutrient contents of
Calotropis procera. Sixty-three permanent stands
(5 9 5 m) were selected to represent the micro-variations
in four urban habitats of C. procera in Cairo, Egypt. C.
procera populations showed significant variations in the
size structure, biomass and density between the studied
habitats. Size class distribution was bell- or biomodal
shaped in most habitats, which suggests that C. procera
adopts an adult-persistence population survival strategy. It
was characterized by low episodic recruitment rates and
relative stability. C. procera had significant plasticity in
morphological and reproductive traits with changing of soil
edaphic factors in urban habitats. Foliar Na, K and P
concentrations were significantly different in the studied
habitats, in addition to their significant correlations with
the same elements in soil. The variation in the functional
traits of the plant indicated its ability to persist under urban
habitat conditions. It is likely that C. procera may dominate
in the future the urban habitats under extensive
degradation of the natural habitats of native species.

Calotropis procera (Aiton) W.T (Asclepiadaceae) (Giant milkweed) is a xerophytic perennial shrub ... more Calotropis procera (Aiton) W.T (Asclepiadaceae)
(Giant milkweed) is a xerophytic perennial shrub or
small tree. It is native to tropical and subtropical Africa,
Asia and common in the Middle East. It grows on a variety
of soils, from fine to coarse texture, with varying degrees of
salinity. The importance of C. procera in the functioning of
ecosystems is reflected in its hosting of butterflies, while it
also acts as a food plant for arthropods. In addition, it is
used for medicinal purposes in many arid countries.
Potential new uses of this species in semi-arid regions
include the phytoremediation of soils contaminated with
trace elements and the use of biomass as a source of
renewable energy.

• We studied the impacts of treated wastewater (TWW) on nutrients concentrations in green and sen... more • We studied the impacts of treated wastewater (TWW) on nutrients concentrations in green and senesced leaves of Cupressus sempervirens and soil in three desert plantations • The species accumulated high amounts of Zn, Mn, Cu and Cd in senesced leaves compared to green • Transfer factor of Zn and Cu from soil to trees was 2-15 times > that reported for forage crops • Stoichiometric ratios were decreased under TWW irrigation • A considerable amount of heavy metals return by senesced leaves to soil a b s t r a c t Wastewater reuse for agriculture is an important management strategy in areas with limited freshwater resources , yielding potential economic and environmental benefits. Here the effects of long-term irrigation with wastewater on the nutrient contents of green and senesced leaves of Cupressus sempervirens L. were assessed for three planted forests in Egypt. Stoichiometric ratios, transfer factors for nutrients from soil to plant and enrichment factors in contaminated soils were estimated and compared to a ground water irrigated control site. Under wastewater irrigation, C. sempervirens transferred most of the estimated nutrients, particularly heavy metals, from green to senesced leaves. This could be a self-protecting mechanism under continuous wastewater irrigation. The accumulation of four metals (Zn, Mn, Cu and Cd) with transfer factors N 1 for wastewater-irrigated trees, indicated the ability for metal accumulation of C. sempervirens. Stoichiometric ratios decreased under wastewater irrigation compared to the control site and global trends, which suggests nutrient disorders in these plants. The values of enrichment factors in the wastewater-irrigated soils showed remarkable availability and distribution of metals. Decreased resorption of metals by senesced leaves of C. sempervirens will add considerable amount of these metals to the soils, which will likely have adverse affects on the desert ecosystem components.

Trees growing at their altitudinal or latitudinal distribution in Fennoscandia have been widely u... more Trees growing at their altitudinal or latitudinal distribution in Fennoscandia have been widely used to reconstruct warm season temperatures, and the region hosts some of the world's longest tree-ring chronologies. These multi-millennial long chronologies have mainly been built from tree remains found in lakes (subfossil wood from lake-shore trees). We used a unique dataset of Scots pine tree-ring data collected from wood remains found on a mountain slope in the central Scandinavian Mountains, yielding a chronology spanning over much of the last 1200 years. This data was compared with a local subfossil wood chronology with the aim to (1) describe growth variability in two environments during the Medieval Climate Anomaly (MCA) and the early Little Ice Age (LIA), and (2) investigate differences in growth characteristics during these contrasting periods. It was shown that the local tree-line during both the MCA and early LIA was almost 150 m higher that at present. Based on living pines from the two environments, tree-line pine growth was strongly associated with midsummer temperatures, while the lake-shore trees showed an additional response to summer precipitation. During the MCA, regarded to be a period of favorable climate in the region, the tree-ring data from both environments showed strong coherency and moderate growth variability. In the early LIA, the two chronologies were less coherent, with the tree-line chronology showing more variability, suggesting different growth responses in the two environments during this period of less favorable growing conditions. Our results indicate that tree-ring width chronologies mainly based on lake-shore trees may need to be re-evaluated.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights

We assessed growth differences and the foliar traits underpinning production in paired samples of... more We assessed growth differences and the foliar traits underpinning production in paired samples of juvenile American beech (Fagus grandifolia Ehrh.) that originated from seed versus root sprouts. Root sprouts had significantly greater relative extension growth rate and slightly greater leaf mass per unit area compared to seed-derived individuals, but neither light-saturated net photosynthetic rate nor foliar chlorophyll and nitrogen concentrations differed significantly between paired seedlings and sprouts. The greater height growth rate of saplings originating as root sprouts does not result from differing foliar function, but rather depends on translocation of assimilates from the parent tree to sustain this unusual and ecologically important dual regeneration strategy in American beech.

The aim of this study is to estimate the total above-ground biomass (TAGB), stem height (H), diam... more The aim of this study is to estimate the total above-ground biomass (TAGB), stem height (H), diameter at breast height (dbh) and basal area of five tree species (ages 7 – 8 years) irrigated by municipal sewage water in the Egyptian-Chinese friendship forest, Sadat City, Egypt. From the biomass data that obtained through destructive sampling, models for predicting aboveground biomass were developed. The highest values for stem density and height were estimated for Eucalyptus citriodora, while the lowest value for density was obtained for Dalbergia sissoo and stem height for Khaya senegalensis. The highest values for basal area and dbh were obtained for Casuarina spp., while the lowest values were recorded for Dalbergia sissoo. Eucalyptus camaldulensis had the highest stand stem biomass and TAGB (55.5, 83.9 t DW ha –1 , respectively). In addition, Casuarina spp. had the highest leafy branches bio-mass (32.5 t DW ha –1) while Dalbergia sissoo had the lowest values for all tree components. All the generated allometric equations had high correlation coefficients at high probability levels. Moreover, the results revealed that not only the dbh data can be used as independent variable for biomass determination , but also stem height and size index are recommended for biomass estimation.

AFRICAN JOURNAL OF BIOTECHNOLOGY

Environmental monitoring and assessment, 2015

The present study aims at identifying and analyzing the ornamental vegetation of Qanatir Public P... more The present study aims at identifying and analyzing the ornamental vegetation of Qanatir Public Park in the southern section of the Nile Delta, Egypt. One hundred and twelve ornamental species; belonging to 91 genera and 45 families and represented by 4449 individuals are cultivated recorded in the Qanatir Public Park. The highly represented families are Leguminosae (14.2 %), Palmae (8%) and Moraceae (7.1%). Each of Apocynaceae, Myrtaceae and Verbenaceae are represented by 6 species (5.3%). Moreover, 8 families are represented by 2 species, and 27 families are represented by only one species. The classification of these species according to the common horticultural categories indicates that trees and shrubs have the highest contribution (80 species, 3513 individuals), while cycads (palm-like) have the lowest contribution to the recorded species (1 species, 7 individuals). Many species recorded in Qanatir Park were not recorded in the old gardens in Greater Cairo and some of them are very rare in Egypt such as Sarcocephalus cordatus. The ground weed flora associated with the ornamental plants in the Park, were identified and analyzed. Due to the history and plant wealth of this Park, it is important to develop and activate the role of botanical gardens of Qanatir Park in the local community of Greater Cairo as an educational and cultural park.

African Journal of Biotechnology, 2015

AFRICAN JOURNAL OF BIOTECHNOLOGY

Environmental monitoring and assessment, 2015

African Journal of Biotechnology, 2015