Przedsiewne traktowanie nasion pszenicy w celu indukcji tolerancji na stres solny

The influence of pre-sowing seed treatments on germination, seedling growth, ion accumulation and plant antioxidant system in spring wheat (Triticum aestivum L.) cultivar MH-97 was examined under control and saline conditions. Albeit, all pre-sowing seed treatments were effective in improving seedling fresh and dry weight under saline conditions, the effect of hormonal priming with kinetin was very pronounced particularly in improving seedling vigor. The plants raised from seeds primed with kinetin have maximum root and shoot lengths under saline conditions while pre-sowing chilling treatment increased shoot length maximally whereas halopriming increased root length maximally under non-saline conditions. The Na⁺ uptake was decreased while K⁺ uptake was increased in plants due to hormonal priming with kinetin and hydropriming under stress conditions. Except halopriming, all seed treatments significantly increased leaf protein contents under non-saline conditions, however decreased under saline conditions. Halopriming resulted in a significant increase in protein concentration. Catalase (CAT) activity was significantly increased under salinity stress, however, hormonal priming and halopriming treatments maximally increased CAT activity. All the seed treatments were effective in increasing superoxide dismutase (SOD) level but hormonal priming with kinetin maximally increased its activity under stress conditions. Although all pre-sowing seed treatments were effective in alleviating the adverse effect of the salt stress on wheat plants, their effects on altering the concentration of different ions, seedling growth and plant antioxidant system were different in the wheat plants.Wpływ przedsiewnego traktowania nasion na kiełkowanie, wzrost siewek, akumulację jonów oraz system antyoksydacyjny roślin pszenicy jarej (Triticum aestivum L.) odmiany MH-97 był badany w warunkach normalnych i w warunkach stresu solnego. Chociaż wszystkie przedsiewne traktowania nasion skutecznie poprawiały ilość świeżej i suchej masy siewek w warunkach stresu solnego, wpływ traktowania hormonami (kinetyną) był szczególnie wyraźny w poprawie żywotności siewek. Rośliny otrzymane z nasion traktowanych kinetyną miały największą długość korzenia i pędu w warunkach stresu solnego, podczas gdy przedsiewne chłodzenie nasion najbardziej stymulowało wzrost pędu, a traktowanie nasion roztworem soli (halopriming) najbardziej stymulowało wzrost korzenia w warunkach kontrolnych. Pobieranie Na⁺ było mniejsze, natomiast pobieranie K⁺ większe u roślin traktowanych kinetyną lub wodą w warunkach stresu. Za wyjątkiem osmokondycjonowania, wszystkie metody traktowania nasion znacznie zwiększały zawartość białka w liściach w warunkach bez stresu solnego, a zmniejszały w warunkach stresu solnego. Osmokondycjonowanie powodowało znaczny wzrost stężenia białek. Aktywność katalazy (CAT) wzrastała w warunkach stresu solnego, jednakże traktowanie hormonami i osmokondycjonowanie maksymalnie zwiększało aktywność CAT. Wszystkie metody traktowania nasion były skuteczne w podnoszeniu poziomu dysmutazy ponadtlenkowej (SOD) ale traktowanie kinetyną maksymalnie zwiększało jej aktywność w warunkach stresu. Chociaż wszystkie metody przedsiewnego traktowania nasion były skuteczne w łagodzeniu niekorzystnego wpływu stresu solnego na rośliny pszenicy, ich wpływ na zmianę stężenia różnych jonów, wzrostu siewek i systemu antyoksydacyjnego roślin różnił się w różnych roślinach pszenicy

Responses of Canola to Different Row and Plant Spacings

A field study was carried out to determine growth and yield of canola (Brassica napus L.) at different inter row (30, 45, and 60 cm) and intra row (10, 15, and 20 cm) spacing between 1995-97. The closer row Spacing of 30 cm significantly increased leaf area index (LAD, total dry matter (TDM) in both the seasons over wider spacing of 45 and 60 cm. Similarly closer plant spacing of 10 cm also enhanced LA! and TDM over 15 or 20 cm plant spacing. Seed and oil yield was significantly increased in first row spacing compared with 45 or 60 cm row spacing in both seasons. Swd yield was linearly related to TDM yield, harvest index was not changed. The results suggest that closer spacing of 30 cm is optimum for maximizing seed and oil yield for canola under the agro-ecological conditions of Faisalabad

Czy kondycjonowanie wzmaga kiełkowanie nasion i wschody aksamitki (Tagetes patula L.) poprzez wywołanie zmian fizjologicznych i biochemicznych?

Poor plant stand establishment is a common problem for marigold production. Exposure to seed priming is one of the strategies being used to accelerate the activation of plant growth, especially seed germination in many crops. Therefore, an experiment was conducted to investigate the influence of different seed priming techniques on performance of French marigold. For this purpose, different seed priming techniques: hydroprimng, 50 mM CaCl2, 100 mg L⁻¹ salicylic acid and 100 mg L⁻¹ ascorbic acid were assessed. Seeds without any treatment were considered as control. Priming with 50 mM CaCl2 was proved to be the most effective treatment in enhancing germination and seedling vigour among all other treatments including control as shown by higher final germination/emergence, germination energy and lower mean germination/emergence time. Furthermore, positive correlation between reducing sugars and dry weight and α-amylase activity and the concentration of reducing sugars indicates that enhancement due to priming could be attributed to higher reducing and total sugars as well as higher α-amylase activity in primed seeds.Słabe wschody to powszechny problem w produkcji aksamitki. Kondycjonowanie jest jedną ze strategii stosowanych w celu przyspieszenia wzrostu roślin, zwłaszcza kiełkowania nasion. Przeprowadzono więc eksperyment mający na celu zbadanie wpływu różnych technik kondycjonowania na rozwój aksamitki. Oceniono różne techniki kondycjonowania nasion: hydrokondycjonowanie, 50 mM CaCl2, 100 mg L⁻¹ kwasu salicylowego oraz 100 mg L⁻¹ kwasu askorbinowego. Kontrolę stanowiły nasiona bez żadnych zabiegów. Okazało się, że kondycjonowanie za pomocą 50 mM CaCl2 było najbardziej skutecznym zabiegiem wzmagającym kiełkowanie i żywotność siewek w porównaniu ze wszystkimi innymi zabiegami, łącznie z kontrolą, co było widoczne na podstawie wyższego końcowego kiełkowania/wschodów, energii kiełkowania oraz mniejszego czasu kiełkowania/wschodów. Ponadto, dodatnia korelacja między cukrami redukującymi a suchą masą i aktywnością α-amylazy a także stężenie cukrów redukujących wskazujące na wzmożony wzrost będący efektem kondycjonowania można przypisywać wyższej zawartości cukrów redukujących i całkowitej zawartości cukrów oraz wyższej aktywności α-amylazy w nasionach poddanych kondycjonowaniu

Plant drought stress: effects, mechanisms and management

Scarcity of water is a severe environmental constraint to plant productivity. Drought-induced loss in crop yield probably exceeds losses from all other causes, since both the severity and duration of the stress are critical. Here, we have reviewed the effects of drought stress on the growth, phenology, water and nutrient relations, photosynthesis, assimilate partitioning, and respiration in plants. This article also describes the mechanism of drought resistance in plants on a morphological, physiological and molecular basis. Various management strategies have been proposed to cope with drought stress. Drought stress reduces leaf size, stem extension and root proliferation, disturbs plant water relations and reduces water-use efficiency. Plants display a variety of physiological and biochemical responses at cellular and whole-organism levels towards prevailing drought stress, thus making it a complex phenomenon. CO$_{2}$ assimilation by leaves is reduced mainly by stomatal closure, membrane damage and disturbed activity of various enzymes, especially those of CO$_{2}$ fixation and adenosine triphosphate synthesis. Enhanced metabolite flux through the photorespiratory pathway increases the oxidative load on the tissues as both processes generate reactive oxygen species. Injury caused by reactive oxygen species to biological macromolecules under drought stress is among the major deterrents to growth. Plants display a range of mechanisms to withstand drought stress. The major mechanisms include curtailed water loss by increased diffusive resistance, enhanced water uptake with prolific and deep root systems and its efficient use, and smaller and succulent leaves to reduce the transpirational loss. Among the nutrients, potassium ions help in osmotic adjustment; silicon increases root endodermal silicification and improves the cell water balance. Low-molecular-weight osmolytes, including glycinebetaine, proline and other amino acids, organic acids, and polyols, are crucial to sustain cellular functions under drought. Plant growth substances such as salicylic acid, auxins, gibberrellins, cytokinin and abscisic acid modulate the plant responses towards drought. Polyamines, citrulline and several enzymes act as antioxidants and reduce the adverse effects of water deficit. At molecular levels several drought-responsive genes and transcription factors have been identified, such as the dehydration-responsive element-binding gene, aquaporin, late embryogenesis abundant proteins and dehydrins. Plant drought tolerance can be managed by adopting strategies such as mass screening and breeding, marker-assisted selection and exogenous application of hormones and osmoprotectants to seed or growing plants, as well as engineering for drought resistance

Cadmium contamination of soils and crops by long term use of raw effluent, ground and canal waters in agricultural lands

Water scarcity in agriculture sector forced farmers to use city wastewater without any regard of its quality effects on environment and resultant contamination of soils and plants, particularly with heavy metals. A survey of effluent, tube well and canal water irrigated areas in Faisalabad, Pakistan was conducted to appraise Cd concentration in these waters and soils, and its uptake by cereal and legume crops. Water, soil and plant (seeds, shoot & roots) samples were collected and analyzed for Cd concentration. Results illustrated that wastewater contained 11.0 and 3.7 times higher Cd than tube well and canal waters, respectively. Location-wise the lowest Cd concentration was 0.6 ?g L-1 at Bypass Samandari Road (BSR) while the highest was 1.4 ?g L-1 at Malkhanwala (MW). Maximum AB-DTPA extractable Cd (0.30 mg kg-1 & 0.248 mg kg-1) was found in soil samples collected from 0-15 cm depths at Uchkera and Ghulam Muhammad Abad (GMA), respectively. It was the lowest (0.04 mg kg-1) in soil samples collected from Chak No. 235/RB (C235) location. Long term effluent irrigation resulted in 248 and 260% increase in Cd contents at 0-15 cm depth of soils compared to tube well and canal waters irrigated soils, respectively. In all the cases, Cd was within safe limits. About 70% of the metal was deposited in upper 30 cm layers. Seeds of effluent irrigated chickpea acquired the highest concentration of Cd (0.177 mg kg-1), while was the lowest in wheat seeds (0.034 mg kg-1). Concentration of Cd was higher in mungbean shoots (0.62 mg kg-1) than in wheat shoots. The order for Cd concentration in seeds was chickpea > maize > mungbean > wheat for wastewater irrigated crops. Similar trend of Cd concentration was observed in tube well and canal waters irrigated crops

Comparative Productivity and Seed Nutrition of Cotton by Plant Growth Regulation under Deficient and Adequate Boron Conditions

<div><p>ABSTRACT: Plant growth regulators (PGRs) potentially improve the productivity and nutritional quality of crops through modulation of morphology, physiology and nutrient dynamics within plants. However, the effect of PGRs may differ under environments with deficient and adequate nutrients. Here the role of mepiquat chloride (MC) on the yield and seed nutritional quality of cotton was explored under boron (B) deficiency and adequate conditions in a two-year field study. Mepiquat chloride was foliar-applied at different dosages (0 and 70 mg L-1) and growth stages (squaring and flowering) and B was applied into soil (0, 1, 1.5, 2 and 2.5 kg ha-1) to establish B deficiency and adequate levels. Seed cotton yield and seed nutritional quality were substantially higher under adequate B conditions, compared to B deficiency. Nonetheless, MC applications improved the seed cotton yield, seed oil yield, seed protein yield and concentration of seed mineral nutrients (N, P, K, B, Zn and Fe except for Mn) under both B deficiency and adequate conditions. Nonetheless, the improvement in all traits caused by MC application was greater under adequate B conditions (2-2.5 kg ha-1 B), compared to B deficiency conditions. Furthermore, the application of MC at squaring proved more beneficial in improving the seed cotton yield and nutritional quality, compared to the flowering stage. In conclusion, MC application improves seed cotton yield and cotton seed nutritional quality under both deficient and adequate B conditions, through an improved nutrient accumulation in seed tissues; however, the efficacy of MC is affected by B deficiency.</p></div

Pobudzanie etanolem: skuteczna metoda wzmagająca kiełkowanie i rozwój siewek poprzez ulepszenie systemu antyoksydacyjnego u nasion pomidora

Tomatoes reportedly have a positive response to seed priming. The present study evaluates the effects of ethanol priming on germination, seedling vigour and antioxidative responses of tomato seeds. Priming was achieved by exposing seeds of ‘Roma’ and ‘Nagina’ to 2, 4 and 6% aerated ethanol solutions for 24 h. Priming with low levels (2 and 4%) of ethanol improved seed germination, seedling vigour and enhanced antioxidative activity that results in better performance of tomato seeds. However, priming with 6% ethanol failed to improve seed germination and seedling development which relates to the decreased anti-oxidative activity in tomato seeds due to high ethanol level.Uważa się, że pomidory wykazują pozytywną reakcję na pobudzanie nasion. Niniejsze badanie ocenia wpływ pobudzania etanolem na kiełkowanie, żywotność siewek oraz antyoksydacyjne reakcje nasion pomidora. Pobudzanie osiągnięto działając na nasiona odmian ‘Roma” i „Nagina” 2, 4 i 6% napowietrzonymi roztworami etanoli przez 24 godziny. Pobudzanie za pomocą niskich poziomów (2 i 4%) etanolu poprawiało kiełkowanie nasion, żywotność siewek oraz wzmagało aktywność antyoksydacyjną, która daje lepsze wyniki w odniesieniu do nasion pomidora. Jednak pobudzanie 6% etanolem nie polepszyło kiełkowania nasion ani rozwoju siewek, co ma związek z obniżoną aktywnością antyoksydacyjną u nasion pomidora ze względu na wysoki poziom etanolu