Two field experiments were carried out in 2017 and 2018 to evaluate the impacts of salicylic acid (1?mM SA) and putrescine (1?mM Put) on leaf osmolytes, seed reserve and oil accumulation and fatty acid composition of rapeseed (Brassica napus L.) under different watering levels (irrigations after 70 and 150?mm evaporation as normal irrigation and severe drought stress, and 70?→?90?→?110?→?130?→?150 and 70?→?100?→?130→150 as gradual and moderately gradual water deficits, respectively). The experiments were laid out as split plot on the bases of randomized complete block design in three replications. Water stress increased the contents of glycine betaine, proline, soluble sugars, and proteins. Application of SA and Put further enhanced the contents of glycine betaine and soluble sugars, while reduced proline content of leaves. Seed filling duration, seeds per plant, plant biomass and seed yield were decreased with increasing irrigation intervals. Exogenous SA and Put enhanced all of these parameters under different irrigation intervals. Oil accumulation in seeds was diminished as water stress severed. The gradual water deficit considerably reduced the impacts of drought stress on yield related traits and oil content per seed, due to stress acclimation of plants. Oil content of seeds was augmented by SA and Put treatments through prolonging seed filling duration, particularly under limited irrigations. Percentages of palmitic acid and stearic acid (saturated fatty acids) were not affected by water limitation. However, unsaturated fatty acids of linoleic and linolenic acids were reduced, and oleic acid was enhanced due to water shortage. Unsaturation index was improved by SA and Put treatments under severe water stress as a result of decreasing oleic acid and increasing linoleic and linolenic acids contents. The SA spray was the best treatment for improving rapeseed seed and oil production under normal and stressful conditions.
相似文献To investigate the effect of different planting dates and irrigation regimes on six canola cultivars, a 2-year (2014–2016) experiment was conducted at the Seed and Plant Improvement Institute of Karaj. The experiments were conducted as the factorial split-plot in a randomized complete block design including six canola cultivars (Gabriella, Brutus, Triangle, Marathon, Danube, and Natali), two irrigation regimes (fully irrigated and irrigation termination at the flowering stage) and two planting dates (October 1 and November 1). The results showed that irrigation termination from the flowering stage prevented the supply of required material for filling the seeds and the metabolism of the seed compounds and reduced the growth period of the seed. Therefore, a reduction was observed in the content of oleic and linoleic acids and proline. Also, water deficit stress caused an increase in the glucosinolate content of the seed. The response of canola cultivars was different in terms of fatty acids, so that the Natali cultivar had higher palmitic, oleic acids, and proline content compared to the other cultivars at both planting dates. Fully irrigated treatment and planting date of October 1 produced the highest amount of seed and oil yield (4659 and 2073?kg ha?1), palmitic acid (5.5%), and proline (22.7?μmol/g) content, and the lowest glucosinolate content (13.2?mg/g). Generally, the Natali cultivar and planting date of October 1 and the fully irrigated regime are highly recommended in the studied area regarding qualitative traits and yield of canola.
相似文献Developing new tools for using low-quality irrigation waters is vital for the sustainability of irrigated agriculture and minimizing salt accumulation. Therefore, the present study focused on the interactive influence of irrigation treatments (magnetized (MT) and non-magnetized (NMT)) and water salinities (0.38, 1.5, 4.5, and 7.0?dSm?1) on soil salinity, water use efficiency, yield and morpho-physiological changes of Balk?z bean. A pot experiment was conducted in a randomized complete block design with three replications under the rain shelter condition. Irrigation water MT treatment increased fresh bean yield, water use efficiency (WUE) and irrigation water use efficiency (IWUE) by 21.35, 23.00 and 14.8%, respectively, while saturated soil salinity was reduced by 20%, compared to NMT treatments. The leaf area, stomata, and leaf succulence in green beans in the MT treatment significantly increased by 13.4, 23.9, and 3.3% compared with those in the NMT treatment. Stems of the bean crops were more sensitive to salinity stress followed by roots and leaves. The study revealed that irrigation with magnetically treated water manages salinity related yield loss through increased morphological features as well as osmotic and stomatal adjustments. In addition, the bean crops showed an ability to protect water in tissue against salinity toxicity up to 5.24?dSm?1 soil salinity level under magnetized saline water conditions. Finally, irrigation with magnetically treated 0.38?dSm?1 irrigation water can be recommended due to providing a higher yield, WUE, IWUE, and sustainable production under saline irrigation in water scarcity regions.
相似文献NERICA rice was developed through the hybridization of Oryza Glaberrima and Oryza sativa in an attempt to produce a higher yield in areas with a limited water supply. This study investigated the interactive effects of irrigation water salinities (0.38, 1.5, 3.0, 5.0, 7.0, 10.0 and 15?dSm?1) for various water depths (5, 10 and 15?cm) on crop yield and related components of NERICA rice variety. This study showed that increased levels of irrigation water salinity resulted in reduced rice yield, biomass weight, plant height, harvest index, 1000 grain weight, evapotranspiration, water use efficiency, stomatal conductance, and chlorophyll content, and increased plant sterility for all irrigation water depths. The threshold values of soil salinity for the NERICA rice for the 5, 10, and 15?cm depths were 2.14, 81 2.80, and 1.98 dSm?1, respectively. The study showed that the optimum salinity/water depth condition for the production of transplanted NERICA rice is irrigation water salinity <?1.50 dSm?1, and a 10?cm water depth. This irrigation water salinity level maintains the soil ECe at or below the salinity threshold value of 2.80 dSm?1. This study showed that NERICA rice has a salinity threshold value of 2.80 dSm?1. Since rice is generally considered to be more salt-sensitive during germination, it is recommended that farmers apply the least saline water available during the rice germination stage of growth. Information from this study will assist policymakers and farmers to better manage NERICA production in Sub-Saharan Africa.
相似文献The aim of this study was to evaluate the water and nitrogen use efficiency and some quantitative and qualitative characteristics of forage beet cultivars under the influence of different irrigation methods and nitrogen levels in two cropping years, 2017–18 and 2018–19, at Agricultural Research Station in Karaj, Iran. Experimental factors included the first factor with four irrigation methods (normal leakage, alternate furrow irrigation, fixed furrow irrigation, type (drip-strip)), the second factor was the amount of nitrogen fertilizer with three levels (150, 200 and 250?kg N ha?1) and the third factor included three forage beet cultivars (Sbsi052, Jamon and Kyros). Among irrigation treatments, alternate furrow irrigation and fixed furrow irrigation had the highest sugar content with 9.28% and 9.17%, respectively. The highest yield of digestible organic matter was obtained in leakage irrigation treatment, nitrogen fertilizer of 250?kg ha?1 and in Kyros at the rate of 19.45?t ha?1. The highest yield of root digestible dry matter, potassium, sodium and free nitrogen was observed in leakage irrigation treatment and consumption of 200?kg ha?1 nitrogen was observed in foreign cultivars. The highest crude protein was observed in alternate furrow irrigation conditions with a consumption of 200?kg ha?1 nitrogen in cultivar Sbsi052 at 13.08%. Leakage irrigation and type tape had the highest consumption efficiency and efficiency of nitrogen uptake with application of 150 and 200?kg ha?1 N, and the highest water use efficiency was also observed in leakage irrigation and type tape with application of 250?kg ha?1 N in domestic and foreign cultivars. The type irrigation method showed better quantitative and qualitative yield than the furrow irrigation methods.
相似文献Water resources are increasingly scarce, and in drought prone production systems, the capability of the plant to recover its adverse effects is important for yield stability. There is an urgent need to develop water-saving strategies for wheat production. Water stress at critical growth stages diminishes wheat production and has harmful effects on crop growth and development; however, regulated water deficit and potassium foliar application ameliorates its adverse effect up to a certain extent. Consequently, the water deficit effect at different growth stages of the crop with exogenous application of potassium was evaluated in a screenhouse experiment in a complete randomized design (CRD) having four repeats. Varieties of wheat, i.e. Lalma (drought resistant) and Pakhtunkhwa-2015 (drought susceptible), were sown. Water deficit, i.e. mild water stress (50% of water required for field capacity) and severe stress (no application of water), at different growth stages of the crop were imposed. Potassium (K) foliar spray (1%) from potassium sulfate (K2SO4) was applied at the respective stage subjected to water deficit levels. Internal water status, i.e. relative water content (RWC) and water retention capacity (WRC), were attained maximum at tillering stage under mild stress than the rest of the stages with maximum for Lalma. Conversely, water saturation deficit (WSD) and water uptake capacity (WUC) were higher under severe stress imposed at grain filling stage. Theses indices were maintained by foliar potassium application. Similarly, dry matter (DM) allocation varied for stress level imposition and translocation to other parts were improved under foliar K application. The chlorophyll indices, i.e., soil plant analysis development (SPAD) value, also decreased with the severity of water deficit. Grain yield was higher under stress imposition at grain filling stage than the rest of the stages, though severe water stress decreased yield significantly. The Potassium (K) foliar spray showed no prominent effect at grain filling. Canopy temperature increased with stress severity and was maintained under K foliar spray. Osmotic adjustment, water and turgor potential were affected by water stress and maintained with foliar K spray. Grain quality and biochemical traits of wheat were affected severely under water deficit. Potassium foliar spray was found to decrease the adverse effect of the water stress and hence maintained the quality and biochemical characters. It is concluded that application of foliar potassium decreases the adverse effects of water stress at any growth stage, minimises the stress indices drastic effect and maintains the internal water balance of the crop at different stages subjected to water deficit.
相似文献In this study, effects of different sowing dates and seeding rates on N uptake efficiency (NUE), N translocation efficiency (NTE), agronomic efficiency (AE), physiological efficiency (PE), water use efficiency for grain yield (WUEg) and water use efficiency for biomass (WUEb) of facultative wheat were investigated. As the average of cropping year, sowing dates and seeding rates, N uptake efficiency (NUE), N translocation efficiency (NTE), agronomic efficiency (AE), physiological efficiency (PE), water use efficiency for grain yield (WUEg) and water use efficiency for biomass (WUEb) values were respectively obtained as 1.17?kg Nuptake/kg Napplied, 68.5%, 36.9?kg grain/kg Napplied, 31.2?kg grain/kg Nuptake, 5.19?kg ha?1 mm?1 and 18.04?kg ha?1 mm?1.
Nitrogen and water use efficiencies decreased with delayed sowing dates and increased with increasing seeding rates. It is possible to maintain a high wheat yield, nitrogen and water use efficiency by increasing plant density through winter sowing. It was concluded based on present findings that sowing date and seeding rates had significant effects on nitrogen and water use efficiencies and winter sowing should be practiced as not to cause yield losses and high seeding rates (575 seeds m?2) yielded greater nitrogen-water use efficiencies.
相似文献Wheat (Triticum aestivum L.) is a staple food in many countries and is regarded as a vital source of nutrition. Drought is one the most prevalent limitations to wheat growth and development. Herein a two year study was conducted using 25 diverse wheat genotypes obtained from the gene pool of various research institutes of Pakistan to characterize their drought tolerance using various physiological indices like relative water content (RWC), relative dry weight (RDW), water saturation deficit (WSD), relative water loss (RWL), flag leaf area (LA), chlorophyll content index (CC) and their association with the grain yield (GY). Analysis of variance (ANOVA) indicated the presence of significant amount of differences and genetic diversity among genotypes under study. Correlation analysis exposed positive association of CC and LA with GY. However, RWC was shown to have a highly significant and negative association with WSD and RWL. Principal component analysis (PCA) showed that out of the 7 PCs only 2 were significant having eigenvalues >?1; cumulatively accounting for 88.70% and 73.03% of the total variation under control and drought stress conditions, respectively. Strikingly the results of the PCA biplots and cluster heat map exposed G1 (Barani-17), G2 (Dharabi-11), G3 (Ehsan-16), G4 (Chakwal-50), G17 (Ujala-2016) and G23 (Kohistan-97) as potential drought tolerant genotypes. Selection of the positively associated indices would be fruitful and the tolerant genotypes having drought tolerance potential could be utilized in future wheat breeding programs to develop high yielding and drought tolerant genotypes.
相似文献Clavibacter michiganensis subsp. michiganensis is a very important pathogen that causes bacterial wilt of tomato (BWT). Biological control of plant diseases is a critical tool for protecting the environment from chemical pollution. Twenty-five isolates of the genus Trichoderma were obtained from a healthy tomato root. Of the 25 isolates, KABOFT4 showed highly antagonistic activity that controlled the growth of C. michiganensis subsp. michiganensis (Cmm7) under in vitro conditions. The 5.8S ribosomal RNA gene and internal transcribed spacer identified the isolate as Trichoderma harzianum KABOFT4. The effect of this isolate as a soil drench and/or foliar application on bacterial wilt under greenhouse conditions was studied. The germination percentage of tomato seed treated with KABOFT4 increased by 36.7% compared to infected seed treated with only the pathogen Cmm7. Under greenhouse conditions, tomato seedlings treated with KABOFT4 as a soil drench, foliar and soil treatment, and foliar treatment had a 61.3, 26.7, and 40% reduced disease severity relative to the infected control, respectively. All treatments had a positive effect on tomato plants that presented as greater vegetative growth and accumulation of dry matter. The best fresh and dry weight was recorded when plants were treated with KABOFT4 as a soil and foliar application. Tomato plants treated with KABOFT4 also had increased total phenol and flavonoid contents in inoculated and non-inoculated plants compared to untreated plants. Under greenhouse conditions, T. harzianum strains can be used as an environmentally friendly way to manage the most economically important tomato disease. The results showed that a native endophytic strain of T. harzianum was a potent biocontrol agent against C. michiganensis subsp. michiganensis. Application of this strain to tomatoes in the greenhouse resulted in a decrease in disease severity and an increase in crop biomass.
相似文献Unlike edaphic factors, it is difficult to control climatic conditions and their changes that affect plant growth and development. To deal with such posture, farmers have to cultivate their crops at the right time. From this point, over two–year of 2014 and 2015, a field experiment was performed at El-Nubaria region, El-Behaira Governorate, Egypt, to assess the response of sunflower to different combinations between sowing dates (early, mid and delayed) and ascorbic acid treatments (with ascorbic acid and without ascorbic acid). Ascorbic acid was sprayed at 30, 40 and 50 days after sowing. The results showed that sowing sunflower in mid sowing (May 21) achieved the highest values of cumulative heat units utilization efficiency as well as all growth and yield traits, while the lowest values were recorded under the delayed sowing date (June 21). Application of ascorbic acid was effective for promoting growth and yield traits under all studied sowing dates. Ascorbic acid achieved 11.6, 10.1, 10.7 and 12.9% increases under early sowing, and 9.5, 6.6, 8.6 and 10.3% increases under delayed sowing in head diameter, seed weight plant?1, seed yield and oil yield, respectively. Comparing to mid sowing?×?without ascorbic acid, application of ascorbic acid alleviated seed yield losses associated early sowing from 15.7–6.6% and from 23.0–16.4% with delayed one. In conclusion, for remediating the thermal stressful impacts of early or late sowing of sunflower, farmers are advised to treat crop plants with ascorbic acid to avoid yield losses.
相似文献The use of herbicides and growth regulators in agricultural crops to reduce vegetative growth is widely studied worldwide. This study aimed to evaluate the agronomic traits of upland rice subjected to low doses of glufosinate-ammonium applied at different development stages. The treatments consisted of five low doses (0; 15; 30; 60; and 100?g a.i. ha?1; a.i.: active ingredient) of glufosinate-ammonium herbicide: a single low dose between active tillering (AT) and floral differentiation (FD); a single low dose after FD; low dose divided into two applications, the first at the beginning of the AT and the second between AT and FD; low dose divided into three applications, the first at the beginning of the AT, the second between AT and FD and the third after the FD, with four replications. The agronomic traits of upland rice were negatively affected due to the application of low doses of glufosinate-ammonium, with reduction in grain yield, 1000-grain weight, number of panicles, full spikelets and spikelets per panicle. Glufosinate-ammonium has no potential to be used as hormesis effect in rice plants due to loss in grain yield.
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