Owing to several presumed health-promoting biological activities, increased attention is being given to natural plant chemicals, especially those frequently entering the human diet. Glucosinolates (GLs) are the main bioactive compounds found in broccoli (Brassica oleracea L. var. italica Plenck). Their regular dietary assumption has been correlated with reduced risk of various types of neoplasms (lung, colon, pancreatic, breast, bladder, and prostate cancers), some degenerative diseases, such as Alzheimer's, and decreased incidence of cardiovascular pathologies. GL's synthesis pathway and regulation mechanism have been elucidated mainly in Arabidopsis. However, nearly 56 putative genes have been identified as involved in the B. oleracea GL pathway. It is widely recognized that there are several pre-harvest (genotype, growing environment, cultural practices, ripening stage, etc.) and post-harvest (harvesting, post-harvest treatments, packaging, storage, etc.) factors that affect GL synthesis, profiles, and levels in broccoli. Understanding how these factors act and interact in driving GL accumulation in the edible parts is essential for developing new broccoli cultivars with improved health-promoting bioactivity. In this regard, any systematic and comprehensive review outlining the effects of pre-and post-harvest factors on the accumulation of GLs in broccoli is not yet available. Thus, the goal of this paper is to fill this gap by giving a synoptic overview of the most relevant and recent literature. The existence of substantial cultivar-to-cultivar variation in GL content in response to pre-harvest factors and post-harvest manipulations has been highlighted and discussed. The paper also stresses the need for adapting particular pre-and post-harvest procedures for each particular genotype in order to maintain nutritious, fresh-like quality throughout the broccoli value chain.

The objective of this work was to perform a comparative analysis of the physiological, biochemical and agronomical parameters of recent and heritage durum wheat cultivars (Triticum durum Desf.) under water-deficit conditions. Five cultivars were grown under irrigated (control) and rainfall (stressed) conditions. Different agro-physiological and biochemical parameters were studied: electrolyte leakage, relative water content, chlorophyll fluorescence, proline, soluble sugars, specific peroxidase activity, yield and drought stress indices. It was revealed that a water deficit increased proline content, electrolyte leakage, soluble sugars and specific peroxidase activity and decreased relative water content, fluorescence and grain yield. According to these parameters and drought stress indices, our investigation indicated that old cultivars are the best-adapted to local conditions and showed characteristics of drought tolerance, while recent cultivars showed more drought susceptibility. Therefore, local cultivars of each country should be kept by farmers and plant breeders to preserve their genetic heritage.

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Intercropping is common practice in many regions of Tunisia, particularly in Cap-Bon where different crops such as tomato, pepper, cucumber, peanut, corn, pearl millet and sorghum are grown together in the same field and at the same time for self-sufficiency. A number of these crops and vegetables are known for their allelopathic activities. The interaction between plants could be within the individuals of the same species (intraspecific interaction or autotoxicity) or between different species (interspecific interaction or teletotoxicity). Little is known about allelopathic interaction of some of these intercropped plants in mixed farming systems in our local conditions. Therefore, the objectives of the present investigation are to evaluate, under laboratory condition, the allelopathic effect of mixed crops, which interacted positively or negatively when cultivated together in the same field. Two plant species were used to study the effects of their aqueous extract on germination and growth of each other (pepper and pearl millet). The results suggested that aqueous extracts from shoots and roots significantly inhibited germination and seedling growth and the inhibitory effects were increased proportionally with the extract concentration. The shoot and root aqueous extract also exhibited intraspecific and interspecific allelopathy. Generally, it was observed that roots were more toxic than shoots. For root extract, the highest inhibition percentage was gained from the effect of pearl millet on pepper (40%) and highest autotoxicity was observed from pearl millet (36%). The effect of shoot extract on germination indicated that the highest reduction (55%) was obtained from pepper shoot extract on pearl millet and highest autotoxicity was observed from pepper which reached (45%). In most cases autotoxicity appeared to be more severe than teletotoxicity, on seed germination of the two intercropped plant species. DOI: http://dx.doi.org/10.3126/ije.v3i1.9940 International Journal of Environment Vol.3(1) 2014: 32-40