No abstract

Milk thistle [Silybum marianum (L.) Gaertn.] is an important medicinal-industrial plant. The medicinal compounds of milk thistle are derived from its seeds. The plant is commercially cultivated for the production of silymarin. Cultivation offers the opportunity to optimise achene yield and silymarin content. Furthermore, efforts should be made to develop new cultivars. The main objective of milk thistle breeding is to develop high yielding cultivars with elevated silymarin content. There are few developed cultivars of milk thistle (e.g. Argintiu, Budakalaszi, Szibilla, Khoreslo, Babak Castle, Mirel, Silma and Silyb). Different genotypes of milk thistle have variable amount of silymarin e.g. a 'Royston' genotype is rich in silymarin (6-10%). Further progress can be made by using the genetic diversity available in abundance in different genotypes. The main concern of the breeder should be to increase the yield and silymarin contents of the seeds. Asynchronous flowering and seed shedding are also major problems in milk thistle cultivation. At the time of harvest, the plants have flower heads at all stages of development resulting non-uniform maturation of seeds. Therefore, a breeding effort in milk thistle should be planned to obtain plants with simultaneous flowering and reduced crop losses. The developed cultivar Argintiu is characterised by simultaneous seed maturation in flower heads. The wild populations, as valuable gene pools, could be exploited for the improvement of milk thistle crop.

It is challenging to predict the changes in weed flora that may occur because of changes in global climate. Limited data are available on the effect of climate change and drought conditions on weed flora and their competitiveness in Southern Europe. Future predictions by scientists indicate reduced and untimely rainfall, along with increased temperatures in this region. Weeds possess a variety of developmental and physiological mechanisms, including senescing, increased leaf cuticular wax deposition, well-developed palisade parenchyma in the leaves, high root/shoot ratio, stomatal closure, peroxidase accumulation and symbiosis with endophytes that enable them to adapt to drought and high temperatures. Because of high adaptability of weeds to adverse environmental conditions, it can be assumed that under future warmer and drier environmental conditions, their growth will be favoured, while the competitiveness of vegetable crops against weeds will be decreased. It is important to highlight that the predicted decrease in overall rainfall levels throughout the year may lead to increased problems of herbicide residues (carryover effects) to following crops. The current paper provides an up-to-date overview of the adaptation mechanisms of weed species commonly found in Southern Europe, in order to expand the available knowledge regarding their response to drought and elevated temperatures. Emphasis is placed on revealing the effects of drought and increased temperatures on vegetable–weed competition and, most importantly, its effect on vegetable crop yield.

Heavy metals accumulation in soils poses a potential threat to ecosystems, which, in turn, threat human health through food chains. Therefore, remediating polluted sites is important to environment and humanity. In this investigation, statice (L. sinuatum) was exposed to Cd (0, 15, 30, 60 mg kg(-1) soil) or Pb (0, 100, 150, 300 mg kg(-1) soil) in a pot experiment to assess its tolerance to each metal and study its phytoaccumulation capability. The benefits of mycorrhization (mixture of Glomus mosseae and G. intraradices) were also studied simultaneously. Single exposure to Cd or Pb reduced the plant growth, but statice was still relatively tolerant to both metals. The plants accumulated both metals in their roots; little was translocated to the shoots. Total Pb and total Cd accumulated by the roots was approximately 2 and 3 times higher in mycorrhizal than non-mycorrhizal plants (49 versus 147 and 595 versus 956 μg plant(-1)) respectively; however, mycorrhization alleviated metal phytotoxicity. The results suggest that statice is a potential candidate to be used as an ornamental plant in lead and cadmium polluted sites, mainly inoculated with arbuscular mycorrhizae. Besides that, it would be useful as a Pb or Cd controlling agent by means of phytostabilization.

Satureja khuzistanica and Satureja rechingeri are two valuable medicinal perennial species endemic to Iran. They grow wild in southwest parts of Iran. These species are rich in carvacrol, with considerable biological activities. In order to study the effects of climate and region conditions on plant height, leaves + flowering shoots yield (drug yield), essential oil content and yield, and carvacrol content, two years field experiments were conducted in two different locations (Andimeshk and Kashkan) in Iran during 2012 and 2013. The result showed that (average of both years) drug yield of either species in Kashkan (2.6 t ha-1) was higher than in Andimeshk (1.05 t ha-1). Drug yield of S. khuzistanica (1.9 t ha-1) in either region was higher than that of S. rechingeri (1.7 t ha-1). S. reshingeri (37.6 ± 3.5 cm) was shorter than S. khuzistanica (40.5 cm) in either location. In Kashkan, the species grew taller (40.9 cm) than in Andimeshk (37.3 cm). In addition, essential oil content of S. rechingeri (4.5 %) in both regions was more than that of S. khuzistanica (1.9%). Essential oil content of both species in Andimeshk (3.3%) was more than in Kashkan (3.1%). Essential oil yield obtained from S. reshigeri (77.3 kg ha-1) was higher than that from S. khuzistanica due to its higher essential oil content. However, neither location nor species significantly affected carvacrol content. Carvacrol was the main component of the essential oil (95.9-96.7%). Overall, the results showed that both species performed better in the cooler region (Kashkan) but with a higher essential oil content in the warmer region (Andimeshk).