Effect of potassium sulfate on quantitative and qualitative characteristics of canola cultivars upon late-season drought stress conditions

In order to reduce the damage caused by late-season drought stress of canola, a factorial split plot experiment was performed on the basis of the randomized complete blocks design with three replications in Karaj, Iran. The treatments were potassium sulfate in two levels, including application and non-application of potassium sulfate, irrigation at three levels including normal irrigation (control), restricted irrigation from the flowering and pod formation stage, as factorial were in main plots and winter canola cultivars including Opera, L72, KR1, GKH3705, GKH0224 were in subplots. The interaction effect of potassium sulfate?×?irrigation?×?cultivar on seed yield, stomatal resistance, oil yield, linoleic acid, linolenic acid and glucosinolate was significant at the 1% level. The promising line of L72 in normal irrigation and application of potassium sulfate and Opera cultivar under late-season drought stress and application of potassium sulfate had the highest seed yield, oil yield and fatty acids composition.     

Effects of drought stress on the seedling growth,development, and metabolic activity in different cultivars of canola

ABSTRACT

The comparative effects of drought stress on seed performance, growth parameters, free proline content, lipid peroxidation, and several antioxidative enzymes activities were studied in both cultivars of Brassica napus L. Drought stress increased mean germination rate and mean of day germination in both cultivars, and its effect was more pronounced in RGS003. The length and dry weight of root increased significantly in both cultivars under drought. RGS003 was more tolerant and obtained more biomass under drought than that of Sarigol. Proline content and pyrroline-5-carboxylate synthetase expression increased in Sarigol under drought. Measurement of malondialdehyde content in seedlings showed that lipid peroxidation was lower in RGS003 than in Sarigol. Antioxidant enzyme activities showed different trends in the two cultivars under drought stress but were higher in RGS003 than in Sarigol. These results suggest that RGS003 is better protected against drought-induced oxidative damage. Lipoxygenase activity only induced under water deficit condition in RGS003. Changes of respiratory enzymes activities of RGS003 subjected to drought stress showed a pattern different with Sarigol. Drought stress induced aconitase activity in RGS003, but it reduced fumarase and succinate dehydrogenase activity in Sarigol. This study showed that RGS003 exhibits a better protection mechanism against oxidative damage and RGS003 is more drought-tolerant than Sarigol possibly by maintaining and/or increasing growth parameters, antioxidant enzyme activities, and respiratory enzymes activities.     

Boron nutrition for improving the quality of diverse canola cultivars

Abstract

Canola (Brassica napus L.), is the most important oilseed crop due to high oil contents and low concentration of erucic acid and glucosinolates. In Pakistan, oil seed production is not sufficient to fulfill the needs of the country. Thus, the planned experiment was aimed to evaluate the performance of different canola cultivars i.e. Faisal Canola, Pakola, PARC Canola hybrid and Rainbow at grown under various soil applied boron (B) levels viz., 0, 1, 2?kg ha^?1 under a rainfed environment. The experiment was laid out in randomized complete block design with four replications. Among the canola cultivars, the maximum seed oil contents were recorded in cultivar ‘Pakola’ whereas, higher linolenic acid and protein were recorded in cultivar ‘Faisal canola’ as compared to other cultivars. A synergistic effect was found between various levels of B and quality parameters of the canola seed; as higher concentration of oil contents were found when B was applied 2?kg ha^?1. Conversely the linolenic acid showed the antagonistic behavior with the various B levels. On the other hand, protein contents, oleic acid and erucic acid revealed non-significant differences under different B application rates. In conclusion, the cultivar ‘Pakola’ provided the highest oil content when the B was applied at 2?kg ha^?1; the low concentration of unsaturated fatty acid was observed in ‘PARC canola’ cultivar in the Pothwar region of Punjab, Pakistan.     

Positive effects of Penconazole on growth of Brassica napus under drought stress

The aim of the present study was to compare the effects of drought on some physiological and biochemical parameters and to assess the inducing effects of Penconazole (PEN) on drought tolerance in two cultivars (RGS003 as a drought tolerant and Sarigol as a drought sensitive) of canola. Plants were treated with various PEG concentrations (0, 5, 10, and 15%) without or with PEN (15 mg l^?1). Decrease in fresh weight (FW) and dry weight (DW) in Sarigol under drought was higher than that of RGS003. Surprisingly, PEN reversed prominently the negative effects of drought on FW and DW in RGS003. Concomitantly, PEN treatment decreased malondialdehyde content in RGS003 under drought. Moreover, higher content of proline in RGS003 under all drought levels could be considered as a factor for drought tolerance of this cultivar. Superoxide dismutase (SOD), catalase (CAT) and Polyphenol oxidase (PPO) activities were induced by PEN in both cultivars under drought. Inducing effects of PEN on phenylalanine ammonia lyase and thyrosine ammonia lyase activities decreased by increasing of drought levels in both cultivars. In summary, PEN alleviated the negative effects of drought in RGS003 cultivar by inducing activities of SOD, CAT and PPO and proline content comparing to Sarigol.     

植物耐旱机制研究进展

干旱环境下植物通过不同耐旱途径抵御干旱胁迫。简介了植物耐旱机制中的渗透调节、质膜保护和抗氧化防御系统,水孔蛋白及其在水分平衡和抗脱水中的作用,胚胎发育晚期丰富表达蛋白(Lea蛋白)等研究进展。     

The effect of micronutrient foliar application on yield,seed quality and some biochemical traits of soybean cultivars under drought stress

Abstract

This experiment carried out as split plot factorial based on a randomized complete block design with three replications during two consecutive years (2015–2016). The main plot consisted of drought stress: complete irrigation, irrigation withholding at R1 stage, irrigation withholding at R2 stage and subplots included foliar application of micronutrients: distilled water (control), zinc sulfate, manganese sulfate and zinc sulfate?+?manganese sulfate and cultivar as: Williams and Zan elite. The results showed that proline and linoleic acid were increased significantly, but chlorophyll a and b, seed yield, protein percentage, oleic and linolenic acids were decreased significantly by irrigation withholding. Also, the maximum values of chlorophyll b, protein percentage and linolenic acid were achieved by Williams. The significant increasing effect of zinc was found on the maximum root and stem proline, chlorophyll b, and oleic, linolenic and linoleic unsaturated fatty acids, meanwhile the maximum leaf proline was obtained by manganese sulfate.     

Effect of drought stress on total protein,essential oil content,and physiological traits of Levisticum officinale Koch

Levisticum officinale Koch is one of the most important plants producing essential oil. An experiment was conducted to determine the effect of drought stress on growth, total protein and essential oil content of L. officinale. The experiment was conducted in a greenhouse, in a completely randomized design using five replications. Aridity levels of field capacity irrigation (as control), ?0.6 and ?1.0 MPa were applied. There was a significant effect of aridity on the leaf area in L. officinale. The highest leaf area values were found in the lowest aridity (FC) level. The root weight and root length in the ?0.6 MPa aridity level were more than that of the control aridity level, but shoot height and shoot weight were highest in the control treatment. The total soluble protein content under ?0.6 MPa drought stress was numerically lower than that in the control treatment, but statistically there was no significant difference between protein contents in the ?0.6 MPa and the control treatment. Compared to the control treatment, the total soluble protein content of L. officinale significantly decreased in the ?1.0 MPa drought treatment. The essential oil content of L. officinale was significantly increased in the ?0.6 MPa drought treatment compared to the control. Compared to control treatment, a significant reduction was found in essential oil content of L. officinale in the ?1.0 MPa aridity treatment. The results suggest that in the drought levels between ?0.6 and ?1.0 MPa, L. officinale could be used for arid and semi-arid lands economical use.     

作物耐旱性与叶片水势简报

用SPAC理论分析大豆、花生、玉米、甘薯4种作物水势分布特点及耐旱性结果表明，植物叶片水势是植物水分状况的较好生理指标，玉米根、叶间水势差为0．293MPa，叶位间水势差为0．067MPa。不同作物叶片水势差异显著，作物叶片水势越高， 其耐旱性越强。     

Soil microbiomes vary in their ability to confer drought tolerance to Arabidopsis

Drought is a major constraint on agricultural production. Crop genetic improvement for drought tolerance has received much attention and there is ample information about the ability of specific soil microbes to influence drought tolerance in plants. However, in nature, plants interact simultaneously with an array of beneficial, benign and pathogenic microbes. There is a need to understand the cumulative effect of these multiple interactions on a plant's ability to overcome abiotic stresses such as drought. The objective of this research was to investigate the potential of whole soil microbiomes to help Arabidopsis thaliana plants deal with drought stress under in vivo conditions. A sympatric microbiome (i.e., having a history of exposure to Arabidopsis at a natural site) significantly increased plant biomass under drought conditions, but caused earlier death rates as a consequence of drought; whereas, the two non-sympatric soils did not influence Arabidopsis biomass. Consistent with this, we observed reduced expression levels for several Arabidopsis drought response marker genes (ATDI21, DREB1A, DREB2A, and NCED3) in the sympatric Arabidopsis soil treatment. Pyrosequencing analysis of the three soil microbiomes used in this study identified 84 bacterial OTUs (3% genetic distance) from 41 genera (Burkholderia, Phormidium, Bacillus, Aminobacter, Acidiphilum and among others) that were significantly higher in the sympatric Arabidopsis soil, as compared to the two non-sympatric soils. In conclusion, we have identified a robust set of Arabidopsis-associated microbes that when present in the soil can modify the plant's ability to sense abiotic stress and increase its biomass production.     

Variation in shoot and root characteristics and their association with drought tolerance in lentil landraces

Lentil (Lens culinaris Medikus subsp. culinaris), generally grown as a rainfed crop, is often subjected to drought. Drought tolerance is closely related to the distribution of root systems in the soil. We studied seedling shoot and root characters in a set of eight randomly selected lentil genotypes collected from Ethiopia, India, Iran, Syria and ICARDA. Each group of genotypes represents a specific adaptation to the environmental conditions associated with its area of origin. The genotypes were evaluated during two seasons (1997 –1999) under field conditions. Thirty-five-day-old seedlings grown in pots in the open air were assessed for stem length, stem weight, taproot length, lateral root number, total root length and total root weight. Combined analyses over 2 years showed that these characters exhibited significant genotypic variability. Stem length, taproot length and lateral root number were highly correlated, both amongst themselves and with yield. High heritability estimates provided reliability in screening based on these traits. Regression analysis showed that stem length alone accounted for 85% of the variance that occurred in seed yield per plant. Cluster analysis showed that the landraces that originated in Iran and Syria, and the breeding lines developed at ICARDA are distinctly different from the lentil accessions that originated in countries at more southerly latitudes (India and Ethiopia). However, of the total of 40 genotypes, only one line (ILL 6002) was strikingly different from all other test genotypes. This line exhibited significantly superior root and shoot traits and yield, and, therefore, is a valuable germplasm for breeding drought tolerant cultivars.     

藜麦种子萌发阶段响应干旱和盐胁迫变化的综合评价

随着我国藜麦产业不断发展和利用边际性土地种植规模的扩大,藜麦种子萌发阶段对干旱和盐胁迫的响应研究越来越受到重视。本文采用室内PEG-6000模拟干旱胁迫和NaCl模拟盐胁迫,通过测定发芽率、发芽势、长度和鲜重等8个指标,对5个藜麦品种(系)(‘南非2号’‘陇藜1号’‘陇藜4号’、HTH-y605、HTH-01)种子萌发期对干旱和盐胁迫的响应进行综合评价研究,并利用主成分分析方法评价藜麦的抗旱性和耐盐性,指出抗旱性和耐盐性的主要评价指标。结果表明:在藜麦萌发阶段抗旱性综合评价中,主成分分析将8个指标归类为2个成分因子,各成分分别以相对长度和相对发芽率载荷量最大,可作为藜麦萌发期抗旱性主要鉴定指标。抗旱性强弱顺序为:‘南非2号’HTH-01‘陇藜4号’‘陇藜1号’HTH-y605。在其耐盐性综合评价中,通过主成分分析将8个指标归类为3个成分因子,相对长度、相对发芽率和相对发芽指数分别为各成分因子上最大的载荷,可以作为藜麦萌发期耐盐性的主要鉴定指标,耐盐性强弱顺序为:HTH-01HTH-y605‘陇藜4号’‘陇藜1号’‘南非2号’。相关性分析结果显示,不同藜麦品种萌发阶段抗旱性与耐盐性之间无明显相关性。研究发现藜麦不同品种在抗旱性和耐盐性具有遗传多样性,其机制有待进一步研究。研究结论对藜麦抗逆机理研究和品种选育有一定的参考价值,为当前中低产田开发利用提供了理论和数据支持。     

Effects of soil tillage,canola (Brassica napus L.) cultivars and planting date on canola yield,and oil and some biological and physical properties of soil

Determination of different agronomical properties including soil-related parameters for enhanced canola (Brassica napus L.) production can be of great significance. Hence, the objectives were to determine the effects of different tillage systems, canola cultivars and different planting dates on: (i) canola yield and oil, and (ii) soil moisture and microbial carbon (C) and nitrogen (N). Two field experiments were planned as split-plot experiments in three replicates. The main plots were different tillage systems including no-tillage (NT), minimum tillage (MT) and conventional tillage (CT), and the subplots were the combination of different canola cultivars (PF and Hyola 401) and different planting dates (PD): 8 and 23 September and 7 October. Soil moisture under CT and PF was significantly less than that of MT and NT, and Hyola 401, respectively. Carbon and N microbial biomass was the highest at NT and on the first PD. The tillage method and planting date also significantly affected canola yield, oil content and the amount, and the number of earthworms. We may conclude that although the amount of yield was the highest at CT, it may be more agronomically sustainable to plant canola under NT or MT earlier during the autumn growing season.     

Variation in the seed and oil yields and oil quality in the Indian germplasm of opium poppy Papaver somniferum

The variation in the seed shape, colour and yield, and content, yield and fatty acid composition of seed oil of 109 accessions of opium poppy Papaver somniferum, (majority of them Indian land races), was investigated. The seeds were white, pale yellow or light brown in colour, reniform or round in shape and varied in size up to three fold. The oil content, seed and the oil yield varied between 26 to 52%, 1.0 to 7.4 g/plant and 0.4 to 2.7 g/plant, respectively. The % content of palmitic, oleic and linoleic acid in the seed oil ranged between 9.3 to 40.0%, 7.5 to 58.4% and 0.7 to 72.7%, respectively. On average basis, the levels of major fatty acids in the seed oil were: oleic (37.1%) > palmitic (27.3%) > linoleic acid (17.2%). The palmitoleic, stearic and linolenic acids were present in the oils of only some of the accessions. Two of the accessions yielded linoleic acid rich seed oil of about the same quality as soybean and maize oils, and in four accessions, the proportion of palmitic, oleic and linoleic acids was roughly equal. The palmitic acid was relatively less and linoleic acid more in the seed oil from accessions rich in oil content. The oil that contained higher amount of oleic acid also contained higher amount of palmitic acid and relatively lower amount of linoleic acid. The correlation analyses revealed a strong positive relationship between seed yield and oil yield (r = +0.81), oil yield and oil content (r = +0.54) and oleic acid and palmitic acid content in the seed oil (r = +0.49), and a weak positive relationship between oil content and linoleic acid content of oil (r = +0.24), and a negative correlation was observed between oil content and palmitic acid content (r = –0.32), palmitic acid and linoleic acid (r = –0.55) and oleic acid and linoleic acid contents of oil (r = –0.68). The observations have permitted selection of accessions that are high seed and oil yielding and/or rich in linoleic, palmitic and oleic acids or containing palmitic, oleic and linoleic acids in about equal amounts.     

种子引发对小麦抗盐及抗旱特性影响综述

小麦是我国北方重要粮食作物,在农业生产中经常受到干旱和盐分胁迫影响,造成减产。种子引发是在种子萌发前用天然或人工合成试剂对种子进行处理,从而提高植物抗逆性的一种简单而有效的方法。在干旱或高盐条件下,利用引发剂对小麦种子引发后,种子萌发提前,幼苗生长发育代谢增强,抗逆境相关生理指标提升,作物抗旱耐盐能力增强,最终产量及质量得到提高。本文阐述了水、有机物、植物激素、生物活性物质、生物、氧化物、无机信号物质等不同种类引发剂对小麦种子引发的作用机理和效果。并总结了种子引发的主要作用机制,如:减少植株对Na~+的吸收,增加对K~+、Ca~(2+)的吸收,减少盐分对生长造成的阻碍;促进可溶性蛋白和可溶性糖等渗透调节物质的合成和积累,细胞内维持高渗透压,有利于根系吸水;诱使胁迫条件下细胞内超氧化物歧化酶、过氧化物酶、过氧化氢酶、抗坏血酸过氧化物酶等抗氧化酶的合成增多、活性增强,有效清除活性氧,维持细胞内氧平衡;调节植物内源激素合成与运输从而使激素水平处于更加适应胁迫条件的平衡状态等。并讨论了引发剂与植物逆境生理研究之间相互补充、相互促进的关系,展望了种子引发在农业方面的发展及应用前景。     

Drought stress tolerance and photoprotection in two varieties of olive tree

Abstract

The olive tree (Olea europaea L.) is adapted to tolerate severe drought and high irradiance levels. Relative electron transport rate (J), photosynthetic efficiency (in terms of F _v /F _m and Φ_PSII), photochemical (qP) and non-photochemical quenching (NPQ) were determined in 2-year old olive plants (cultivars ‘Coratina’ and ‘Biancolilla’) grown under two different light levels (exposed plants, EP, and shaded plants, SP) during a 21-day controlled water deficit. After reaching pre-dawn leaf water potentials of about -6.5 MPa, plants were rewatered for 23 days. During the experimental period, measurements of gas exchange and chlorophyll fluorescence were carried out to study the photosynthetic performance of olive plants. The effect of drought stress and high irradiance levels caused a reduction of gas exchange, J, Φ_PSII and F _v/F _m and this decrease was more marked in EP. Under drought stress, EP showed a higher degree of photoinhibition, a higher NPQ and a lower qP if compared to SP. Coratina was more sensitive to high light and drought stress and had a slower recovery during rewatering. The results confirm that photoprotection is an important factor that affects photosynthetic productivity in olive, and that the degree of this process varies between the cultivars. This information could give a more complete picture of the response of olive trees grown under stressful conditions of semi-arid environments, and could be important for the selection of drought-tolerant cultivars with a high productivity.     

干旱胁迫对河西走廊边缘绿洲甜高粱产量、品质和水分利用效率的影响

为研究能源作物甜高粱在干旱区不同土壤水分条件下的生产力和水分利用状况, 在甘肃河西走廊边缘绿洲区, 对3 种土壤水分(正常水分、中度干旱和重度干旱)条件下甜高粱产量、品质和水分利用效率进行分析。结果表明: 中度干旱胁迫下甜高粱茎秆和整个地上部生物产量最高, 其鲜重分别为77.3 t·hm^-2 和101.1 t·hm^-2, 干重分别为27.6 t·hm^-2 和34.9 t·hm^-2。3 种土壤水分条件下茎秆汁液锤度分别为21.9%(正常水分)、22.1%(中度干旱)和22.4%(重度干旱), 但差异不显著。中度干旱胁迫下甜高粱的水分利用效率最高, 为4.72 kg·m^-3。说明适度的土壤水分亏缺, 不仅有利于甜高粱生产力和品质的提高, 而且更有利于节约水资源。     

干旱胁迫及复水对豌豆根系内源激素含量的影响

采用盆栽试验方法,研究了干旱胁迫及复水对豌豆根系脱落酸(ABA)、吲哚乙酸(IAA)、赤霉素(GA)和玉米素(ZT)等4种内源激素含量的影响.结果表明:不同程度的干旱胁迫均导致各生育期豌豆根系ABA和IAA含量增加,GA和ZT含量减少,且随干旱胁迫程度的加重变化量增大.同时对各生育期豌豆根系内源激素比例产生影响,对ZT与ABA、GA与ABA、GA与IAA、ZT与IAA比例影响较大,对ZT与GA、IAA与ABA比例影响较小.旱后复水可对各生育期豌豆根系内源激素含量产生补偿效应,其补偿量决定于豌豆生育时期、干旱胁迫强度和复水历时.同时促进各生育期豌豆根系内源激素比例发生变化.     

Tolerant varieties and exogenous application of nutrients can effectively manage drought stress in rice

ABSTRACT

Common abiotic stresses in rain-fed rice areas like drought can occur at any phase of crop growth and may occur periodically. Variation in intensity and severity of drought requires the use of different rice varieties and different nutrient management strategies. This study evaluated the morphological and physiological response of contrasting rice cultivars (Rajalaxmi, IR64, and Sahbhagidhan) to various nutrient combinations under water sufficience and scarce conditions. Drought stress at vegetative stage significantly reduced tiller formation, dry matter remobilization, and photosynthesis, leading to around 41.6% yield reduction. The effect of drought stress was more evident in Rajalaxmi and IR64 by a yield reduction of 57.4% and 43.2% as against only 24.3% in Sahbhagidhan. The combined application of nutrients resulted in higher proline accumulation, chlorophyll and carbohydrate concentrations, and photosynthesis and antioxidant enzymes, ultimately better tolerance to drought. This is reflected in higher values of tolerance indices and low scores of leaf drying and leaf rolling, especially for Sahbhagidhan. The combined application of P, K, Ca, Zn, and Fe resulted in 52.9, 53.3, 48.9% higher yield over P or K application. Rice drought tolerance can be managed by combining breeding of drought-tolerant high yielding varieties with the proper application of fertilizer nutrients.     

苦杏仁去皮热风干燥适宜温度提高油脂品质

为探索适宜的杏仁热风干燥温度,以热烫去皮处理后的湿杏仁为试验材料,研究了热风干燥不同温度对杏仁及其油脂的感官、理化和营养品质的影响。结果表明,经热烫去皮、干燥处理后可以得到颜色较浅的杏仁油,有利于提高杏仁油的感官品质,但会造成杏仁油过氧化值显著升高（P<0.05）,油酸、亚油酸、十七碳烯酸、二十碳一烯酸等不饱和脂肪酸的比例和甾醇含量降低,棕榈酸、棕榈油酸、硬脂酸、十七碳烷酸、二十碳烷酸、二十碳一烯酸的比例和总生育酚含量升高,对杏仁油的理化特性和营养品质产生影响。但不同脂肪酸及其伴随物种类、不同温度处理变化幅度不同。随着干燥温度的提高,干燥速率逐渐加快,杏仁及杏仁油的颜色逐渐加深,杏仁油亮度下降,酸价略有升高,但不同干燥温度之间差异不显著（P>0.05）;过氧化值呈上升趋势,且80℃以上干燥处理显著高于40℃和60℃干燥处理（P<0.05）;总不饱和脂肪酸、油酸、亚油酸、十七碳烯酸、二十碳烷酸的比例及β-生育酚、δ-生育酚及总生育酚含量总体呈下降趋势,棕榈油酸、棕榈酸、硬脂酸的比例和β-谷甾醇、总甾醇含量总体呈升高趋势。低温干燥有利于提高杏仁油中生育酚含量,而提高干燥温度则有利于杏仁油中植物甾醇含量的提高。尤其是干燥温度为80℃以上时,杏仁油的品质变化加快。因此,为提高杏仁油理化与营养品质,杏仁脱皮后的干燥宜在80℃以下的较低温度条件下进行。研究结果可为杏仁干燥和高品质杏仁油加工提供参考。