Agronomic Evaluation of Rapeseed Varieties (Brassica napus L.) in Response to Late-Season Water Deficit Stress

Drought is a wide spread limiting problem seriously influencing rapeseed (Brassica napus L.) growth, production and quality, mostly in dryland regions. However, identification and development of resistant varieties is prohibited by destitute of effective selection criteria. The aim of this study was to evaluate the prevention possibility of rapeseed varieties against terminal-season water deficit stress through selecting suitable varieties. Thirty-four rapeseed varieties were tested in a split plot design based on randomized complete block design (RCBD) with four replications for two years (2005- 2006 and 2006-2007) at Seed and Plant Improvement Institute of Karaj, Iran. Two irrigation levels consisting of irrigation after 80 mm evaporation from class “A” pan during full growing season as normal irrigation (I) and water deficit stress (S) by restricting watering from the flowering phase until full maturity were established in main plots, and subplots were devoted to split application of varieties. Water deficit stress caused noticeable decrease in plant height, silique plant-1, seed silique-1, 1000-kernel weight, seed yield, oil percentage, oil yield and harvest index. There were significant positive correlations between seed yield and yield-related components. Meanwhile, the highest correlation was recorded for number of seeds per siliqua (r= 0.64; P<0.01), suggesting that late-season water deficit stress could be used in selecting drough tolerant varieties. Among varieties, ‘Sunday’ produced the highest seed yield (4938 kg ha-1) and oil yield (2317 kg ha -1) in normal irrigation, and ‘ORW20-3002’ had the highest seed yield (2348 kg ha-1) and oil yield (1000 kg ha -1) in water deficit stress conditions. Accordingly, ‘ORW20-3002’ and ‘Sunday’ can be reported as varieties with sustainable productivity in stress and nonstress conditions

Activity of the Photosynthetic Apparatus in Phaseolus vulgaris L. Leaves Under the Cadmium Stress

The development of civilisation, urbanisation and industrialisation cause to ever increasing contamination of the natural environment. Cadmium belongs to this group of chemical elements, which represent a serious threat, not only for the proper development of plants but also for the health of humans and animals. Hence, the interest of scientists in the toxic effects of this kind chemical elements on the various life functions of organisms. The aim of this study was to investigate the effect of cadmium nitrate aqueous solutions on photosynthetic activity and degree of disorganisation of cell membranes in leaves of common bean (Phaseolus vulgaris L. cv. ‘Laurina’). A fully formed second leaves were wetted with cadmium solutions nitrate (Cd(NO3)2) at concentrations of 5 and 10 mM. With the increasing of cadmium concentration and time of its application (20, 40, 60 min and 24 h), the changes in the fluorescence of bean leaves were observed. Under the influence of cadmium ions, damage occurred both on the edge and the central part of the leaves, and then the whole surface. The highest changes of the chlorophyll fluorescence values were observed after 24 h of application the aqueous cadmium solutions. Use of SPAD chlorophyll Meter, the reduction of chlorophyll content was noticed over time. The flow of electrolytes from the bean leaves was increased with the time and concentration of applied cadmium compounds

Agronomic Evaluation of Rapeseed Varieties (Brassica napus L.) in Response to Late-Season Water Deficit Stress

Drought is a wide spread limiting problem seriously influencing rapeseed (Brassica napus L.) growth, production and quality, mostly in dryland regions. However, identification and development of resistant varieties is prohibited by destitute of effective selection criteria. The aim of this study was to evaluate the prevention possibility of rapeseed varieties against terminal-season water deficit stress through selecting suitable varieties. Thirty-four rapeseed varieties were tested in a split plot design based on randomized complete block design (RCBD) with four replications for two years (2005- 2006 and 2006-2007) at Seed and Plant Improvement Institute of Karaj, Iran. Two irrigation levels consisting of irrigation after 80 mm evaporation from class “A” pan during full growing season as normal irrigation (I) and water deficit stress (S) by restricting watering from the flowering phase until full maturity were established in main plots, and subplots were devoted to split application of varieties. Water deficit stress caused noticeable decrease in plant height, silique plant-1, seed silique-1, 1000-kernel weight, seed yield, oil percentage, oil yield and harvest index. There were significant positive correlations between seed yield and yield-related components. Meanwhile, the highest correlation was recorded for number of seeds per siliqua (r= 0.64; P<0.01), suggesting that late-season water deficit stress could be used in selecting drough tolerant varieties. Among varieties, ‘Sunday’ produced the highest seed yield (4938 kg ha-1) and oil yield (2317 kg ha -1) in normal irrigation, and ‘ORW20-3002’ had the highest seed yield (2348 kg ha-1) and oil yield (1000 kg ha -1) in water deficit stress conditions. Accordingly, ‘ORW20-3002’ and ‘Sunday’ can be reported as varieties with sustainable productivity in stress and nonstress conditions

Influence of Volatile Peppermint (Mentha ×piperita L.) Compounds on Germination and Seedling of Radish (Raphanus sativus L. var. radicula Pers.) Growth

The research concerns the influence of volatile compounds contained in dry peppermint leaves (Mentha ×piperita L.) on germination and seedling characteristics of radish (Raphanus sativus L. var. radicula Pers. ‘Półdługa’). 1, 5 and 10 g of dried peppermint leaves were added respectively into containers, and then Petri dishes with radish seeds were placed in each of them. The control was performed without dried mint. Radish seeds treated with volatile mint compounds in the lowest 1g dose germinated similarly to the control sample. The other two doses, 5 and 10 g, inhibited the process of seeds germination. Allelophatins from M. ×piperita at 1 g of dose had also a stimulating effect on the growth of radish seedlings, especially its roots. The growth of underground organs was also observed at 5 and 10 g doses. For radishes grown in the lowest dose of allelopathic compounds, the values of fresh and dry masses and percentage water content were highest. As the dose of emitters increased, a slight decrease in the value of these parameters was observed, as compared to the control

Effect of aqueous extracts of peppermint (Mentha × piperita L.) on the germination and the growth of selected vegetable and cereal seeds

Peppermint (Mentha × piperita L.) is grown in the gardens for its attractive look and multilateral use in the kitchen and medicine. The grown plant spreads very easily producing stolons and could effectively compete with other plant species. For the purpose of this study, the effect of aqueous extracts from dry peppermint leaves was examined on the germination, growth, fresh and dry weight, and electrolytes leakage of 10 species commonly grown in different regions of the world: Beta vulgaris L., Cucumis sativus L., Lactuca sativa L., Lupinus luteus L., Phaseolus vulgaris L., Raphanus sativus L. var. radicula Pers., Sinapis alba L., Lycopersicon esculentum Mill., Triticum aestivum L., and Zea mays L. Several concentrations of the aqueous extracts from peppermint leaves were prepared: 1, 3, 5, 10, and 15%. The seeds germination decreased with increasing concentration of aqueous extracts from peppermint leaves. The seed germination was completely inhibited on Petri dishes with 10 and 15% extracts. The tomato seeds were the most sensitive, they germinated on the distilled water and 1% extract only. The most resistant were the bean seeds that had the highest germination capacity. In general, the growth of seedlings of analyzed species was inhibited by the aqueous extracts from peppermint leaves. However, it was noticed the stimulating effect on the seedling growth of bean and maize on the 1% extract. The aqueous extracts from peppermint leaves caused the electrolyte leakage in all examined species and it raised with increasing extract concentration at the concentration higher than 3%

Allelopathic effect of invasive Canadian goldenrod (Solidago canadensis L.) on early growth of red clover (Trifolium pratense L.)

Solidago canadensis belongs to highly invasive species in Europe, it is established in ruderal, semi-natural and natural communities. To test the traits related to invasiveness, the experiment with the potential of allelopathic compounds produced by the species was conducted. The aqueous extract from the goldenrod leaves was used to examine the germination and early stages of development of Trifolium pratense, the species as an example of fodder plant common in meadows and pastures. Three types of aqueous extract were used: decoction, infusion, and macerate. All extracts of Canadian goldenrod had a negative influence on the germination process of red clover, however, the effect changed in time and type of extract. The most inhibiting influence was documented for the macerate type of aqueous extract. Similarly, the negative influence of macerate was the highest for the length and weight of the seedlings, the content of chlorophyll a and b, and electrolyte leakage. As the procedure of obtaining the macerate is the most like the process of natural extraction of allelopathic substances in nature, there is the practical conclusion to remove the moved biomass of the goldenrod during the restoration process of areas colonised by the species

Germination and growth of radish under influence of nipplewort aqueous extracts

The conducted experiment was aimed at determining the effect of aqueous extracts from dry roots and shoots of common weed nipplewort (Lapsana communis L. subsp. communis) on seeds germination and early growth of radish (Raphanus sativus L. var. radicula Pers.), cultivars ‘Rowa’, ‘Krakowianka’, ‘Półdługa’. The experiment was carried out in the form of Petri dishes tests with 3 different percentage concentrations of extracts (1%, 3% and 5%, respectively). The germination indexes used here revealed that the germination capacity of the radish seeds was significantly inhibited by extracts from the roots and shoots of L. communis subsp. communis. The elongation growth of radish roots and hypocotyls was stimulated to a higher percentage by extracts from nipplewort roots than by extracts from shoots. The fresh and dry mass of the radish seedlings depended on the type (roots/shoots) and concentration of the extract as well as the radish cultivar. The electrolyte leakage was the highest in seedlings watered with 5% extract of nipplewort shoots. The cultivar most sensitive to nipplewort extracts turned out to be ‘Półdługa’, and the least sensitive was ‘Rowa’. The response of radish seeds to nipplewort extracts is probably due to the presence of allelochemical compounds and their synergistic interaction

Germination and growth of radish under influence of nipplewort aqueous extracts

The conducted experiment was aimed at determining the effect of aqueous extracts from dry roots and shoots of common weed nipplewort (Lapsana communis L. subsp. communis) on seeds germination and early growth of radish (Raphanus sativus L. var. radicula Pers.), cultivars ‘Rowa’, ‘Krakowianka’, ‘Półdługa’. The experiment was carried out in the form of Petri dishes tests with 3 different percentage concentrations of extracts (1%, 3% and 5%, respectively). The germination indexes used here revealed that the germination capacity of the radish seeds was significantly inhibited by extracts from the roots and shoots of L. communis subsp. communis. The elongation growth of radish roots and hypocotyls was stimulated to a higher percentage by extracts from nipplewort roots than by extracts from shoots. The fresh and dry mass of the radish seedlings depended on the type (roots/shoots) and concentration of the extract as well as the radish cultivar. The electrolyte leakage was the highest in seedlings watered with 5% extract of nipplewort shoots. The cultivar most sensitive to nipplewort extracts turned out to be ‘Półdługa’, and the least sensitive was ‘Rowa’. The response of radish seeds to nipplewort extracts is probably due to the presence of allelochemical compounds and their synergistic interaction

Effect of Rosa gorenkensis Besser aqueous extracts on germination and early growth of native plant species

In Europe, Rosa gorenkensis Besser is considered an invasive species. However, its negative impact on native flora components or other habitat components has not been described so far. In the experiment, the germination reactions of mono- and dicotyledonous plant seeds to the aqueous extracts of R. gorenkensis were investigated to determine the allelopathic potential of this plant. Seeds of common plants – wild-growing Festuca rubra L. and cultivated Raphanus sativus L. var. radicula Pers. cv. ‘Rowa’ were treated with aqueous extracts from the roots, stalks, leaves, and flowers of rosa at concentrations of 1%, 2.5%, and 5%. Along with the increase in the concentration of allelochemical compounds in the extracts, the negative influence of the extracts on the germination capacity of the tested seeds species was found. Regardless of the type of extract, inhibition of the growth of the underground and aboveground parts of seedlings was also observed. Changes in biomass and water content, depending on the concentration and type of the extract, were found. The greatest differences in the electrolytes leakage in seedlings watered with 5% extracts were revealed. The study showed that the aqueous extracts of leaves and flowers of this species had the greatest allelopathic potential

The Influence of Aqueous Extracts from Stellaria media L. on the Growth of Zea mays L. Cultivars

Plants introduce chemicals into the environment that can be toxic, both for themselves and for other species. Weed infestation of crops is a competition for environmental resources, but at the same time is a source of chemical substances released into the soil, often reducing yield potential. The paper attempts to investigate the allelopathic interaction of aquatic extracts from dry shoots of chickweed Stellaria media L. on germination and development of maize Zea mays L. seedlings of ‘San’, ‘Kidemos’ and ‘DKC 3441’ cultivars. Along with the increase in the concentration of allelopathic substances, a decrease in the germination activity of all tested maize cultivars was observed. Germination percentage as like percentage of control was the highest for seeds germinating on substrates with 1% chickweed extracts and the lowest for seeds watered with 5% extracts. Biometric measurements of seedlings showed that the most sensitive cultivar of maize was ‘DKC 3441’, and the resistant cultivar ‘San’. The relative water content was the highest for seedlings grown on the 5% extracts. Significant differences in the amount of fresh and dry masses of maize seedlings were demonstrated at the highest concentrations of extracts compared to the control. A significant increase in electrolyte leakage compared to the control sample was found in the ‘Kidemos’ cultivar. The lowest differences in the destabilization of the ionic transport through cell membranes for the ‘DKC 3441’ cultivar were demonstrated