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Recognition of the Apocynaceae and Asclepiadaceae as one family or as two separate but related families with five subfamilies was for long highly controversial. Raising some of the subfamilies to the rank of family was also disbutable. To resolve this issue, 55 morphological and palynological characters were recorded in a data matrix comprising a sample of 41 species belonging to 24 genera of Apocynaceae and 75 species from 31 genera of the Asclepiadaceae. The data matrix was subjected to cluster analysis using the Sorensen’smeasure of dissimilarity and Ward's method of clustering in the PC-ORD version 5. Out of three possible interpretations of the result, we opted for that which suggestd considering the five subfamilies Apocynaceae-Rauwolfioideae, Apocynaceae-Apocynoideae, Asclepiadaceae-Asclepiadoideae, Asclepiadaceae-Periplocoideae and Asclepiadaceae-Secamonoideae as five distinct, neatly defined and homogeneous

In Egypt and during the last 50 years, several changes in agricultural practices have affected different components of agro-ecosystems including weed flora. The aim of the present study was to evaluate changes in the weed flora of El-Menoufia Governorate, South of the Nile Delta of Egypt during the period from 1984 to 2018, in response to different agricultural practices. A total of 240 stands were investigated in both spring and summer seasons in order to document the present status of the weed flora. The obtained results were compared to results obtained by other authors in 1984. Results showed major shifts in the weed flora of El-Menoufia Governorate where 67 species out of 146 species were recorded in our study while only 42 species out of 121 species were present in 1984 survey. Changes in the family composition, life form, life span, and chorology were reported. Reasons responsible for such changes have been discussed. Changes in the crop composition, cultivation area of each crop, excessive use of fertilizers and pesticides, changes in irrigation water quality and quantity are the leading change promoters. The high economic importance of the weed flora and the potential threats facing agriculture in Egypt necessitate the formulation of a sustainable strategy for maintaining agro-ecosystems of Egypt and its biodiversity.

Endophytic bacteria colonize plants and live inside them for part of or throughout their life without causing any harm or disease to their hosts. The symbiotic relationship improves the physiology, fitness, and metabolite profile of the plants, while the plants provide food and shelter for the bacteria. The bacteria-induced alterations of the plants offer many possibilities for biotechnological, medicinal, and agricultural applications. The endophytes promote plant growth and fitness through the production of phytohormones or biofertilizers, or by alleviating abiotic and biotic stress tolerance. Strengthening of the plant immune system and suppression of disease are associated with the production of novel antibiotics, secondary metabolites, siderophores, and fertilizers such as nitrogenous or other industrially interesting chemical compounds. Endophytic bacteria can be used for phytoremediation of environmental pollutants or the control of fungal diseases by the production of lytic enzymes such as chitinases and cellulases, and their huge host range allows a broad spectrum of applications to agriculturally and pharmaceutically interesting plant species. More recently, endophytic bacteria have also been used to produce nanoparticles for medical and industrial applications. This review highlights the biotechnological possibilities for bacterial endophyte applications and proposes future goals for their application.

A critical foundation of sustainable agriculture is to understand different agro-ecosystems components and to investigate relations between different species and environmental factors affecting their presence and expansion. The flora of Siwa Oasis agro-ecosystems was investigated and assessed. A total of 132 stands (66 in spring and another 66 in summer) were chosen to represent the study area and its soil properties during spring and summer. Cover of each species and foliage projective cover of each stand was visually estimated. Species richness, diversity and evenness were calculated for each stand. Soil analyses showed that stands could be differentiated geographically. Vegetation and soil relationships were explored using different ecological multivariate techniques. TWINSPAN classification resulted in four ecological groups in spring and four more groups in summer. DCA and DCCA clustered stands in a similar manner to the ecological groups extracted from TWINSPAN classification. Indicator species and correlated soil characteristics of each group were identified. Salinity, crop type, water availability, shade and human intervention are the major factors affecting the diversity and richness of the vegetation communities in Siwa Oasis cultivated land. Some of the species recorded are of high economic importance, highlighting a valuable opportunity to cultivate problematic soils with non-traditional crops.

In this study, 15 bacterial endophytes linked with the leaves of the native medicinal plant Pulicaria incisa were isolated and identified as Agrobacterium fabrum, Acinetobacter radioresistant, Brevibacillus brevis, Bacillus cereus, Bacillus subtilis, Paenibacillus barengoltzii, and Burkholderia cepacia. These isolates exhibited variant tolerances to salt stress and showed high efficacy in indole-3-acetic acid (IAA) production in the absence/presence of tryptophan. The maximum productivity of IAA was recorded for B. cereus BI-8 and B. subtilis BI-10 with values of 117 &plusmn, 6 and 108 &plusmn, 4.6 &mu, g mL&minus, 1, respectively, in the presence of 5 mg mL&minus, 1 tryptophan after 10 days. These two isolates had a high potential in phosphate solubilization and ammonia production, and they showed enzymatic activities for amylase, protease, xylanase, cellulase, chitinase, and catalase. In vitro antagonistic investigation showed their high efficacy against the three phytopathogens Fusarium oxysporum, Alternaria alternata, and Pythium ultimum, with inhibition percentages ranging from 20% &plusmn, 0.2% to 52.6% &plusmn, 0.2% (p &le, 0.05). Therefore, these two endophytic bacteria were used as bio-inoculants for maize seeds, and the results showed that bacterial inoculations significantly increased the root length as well as the fresh and dry weights of the roots compared to the control plants. The Zea mays plant inoculated with the two endophytic strains BI-8 and BI-10 significantly improved (p &le, 0.05) the growth performance as well as the nutrient uptake compared with an un-inoculated plant.

The rapid development and expansion of modern irrigation schemes across arid environments have radically transformed both natural environments and existing agricultural systems over the past century. The consequences for natural and cultural values are often severe, but remain poorly documented for many regions. The present study describes the floristic diversity of an Oasis agro-ecosystem located in Egypt’s hyper-arid Western Desert. A total of 132 sites were chosen to represent the flora of Siwa Oasis agro-ecosystem and 154 species were recorded of which 52 were cultivated. Non-cultivated taxa consisted predominately of therophytes whereby the flora of Siwa is represented by monoregional, biregional and pluriregional elements as well as some cosmopolitan species. During field survey, 55 species were recorded for the first time suggesting the recent introduction of new weeds. Based on previous studies, 36 wetland and orchard species may have become locally extinct due to loss of habitat and extensive transformation of the Oasis agro-ecosystem. Although Siwa does not support any endemic species, this study documents a unique and complex agro-ecosystem shaped by natural and human agents over millennia. Descriptive floristic studies such as presented here are important records during a time of continuing and increasing change throughout arid regions of the world.