Effect of Salinity Stress on Growth and Yield of Forage Genotypes

Salinity is the major limiting factor for forage productivity in southwestern coastal region of Bangladesh. Some introduced forage cultivars have been shown promising adaptability in saline conditions. The objective of this study was to assess the productivity and measure the agronomic characteristics of several introduced grass species with different created soil salinity levels. This study was conducted at the net house of Dr. Purnendu Gain Field Laboratory, Agrotechnology Discipline, and Khulna University during the period from December 2017 to February 2018. The experiment was laid out in a factorial randomized complete block design with seven replications. The experiment consisted of two factor viz. soil salinity levels (S1 = 0.48, S2 = 5.8, S3 = 7.9, S4 = 9.4, S5 = 15 d·Sm−1) and thirteen forage genotypes. Salinity levels and forage genotypes significantly (p < 0.05) influence all the growth parameters and biomass yield. The growth parameters and yield gradually decreased with the advance of soil salinity level. The tallest plant height (109.85 cm) was found in S1 at 90 DAS while the shortest plant (24.53 cm) was obtained in S5 at 90 DAS. Soil salinity had a significant difference (p < 0.001) on plant height at 90 DAS. The highest numbers of tillers (3.36) were found in S1, whereas the lowest (0.48) was in S5 at 75 DAS. Soil salinity had a significant difference (p < 0.001) on Number of tillers at 75 DAS. The highest biomass wt. (29.14 g) was found in S1, while the lowest biomass wt. (3.52 g) was obtained in S5 at 60 DAS. Soil salinity had a significant difference (p < 0.001) on biomass wt. at 60 DAS. The highest dry matter% (DM%) (21.24%) was found in S4, while the lowest DM (18.74%) was obtained in S1 at 60 DAS. Soil salinity had a significant difference (p < 0.001) on dry matter% (DM%) wt. at 90 DAS. The tallest plant height (81.93 cm) was found in Pakchong, while the shortest plant (20.13 cm) was obtained in Endropogan at 60DAS. Soil salinity had a significant difference (p < 0.001) on plant height at 60 DAS. The highest numbers of tillers (3.07) were also found in Napier-3, whereas the lowest (0.80) was in H. Jaumbo at 75 DAS (S1 + S2 + S3 + S4 + S5). Soil salinity had a significant difference (p < 0.001) on Number of tillers at 75 DAS. The highest biomass wt. (38.60 g) was found in Pakchong, while the lowest biomass wt. (4.49 g) was obtained in Oats at 60 DAS. Soil salinity had a significant difference (p < 0.001) on biomass wt. at 60 DAS (S1 + S2 + S3 + S4 + S5). The highest (DM%) was found in Endropogan (24.68%), while the lowest DM (18.37%) was obtained Spelindida. Soil salinity had a significant difference (p < 0.001) on DM at 90 DAS. It can be concluded that Pakchong appears to be highly salt tolerant.

Yield and Water Productivity of Drip-Irrigated Potato under Different Nitrogen Levels and Irrigation Regime with Saline Water in Arid Tunisia

Field studies were conducted on a sandy soil during autumn of 2010 and 2011 in an arid region of Tunisia to investigate the effects of nitrogen and irrigation regimes with saline water on yield and water productivity (WP) of potato (Solanum tuberosum L. cv. Spunta) and soil salinity. For the two years, irrigation treatments consisted in water replacements of cumulated crop evapotranspiration (ETc) at levels of 100% (I100, full irrigation), 60% (I60) and 30% (I30), when the readily available water in I100 treatment was depleted, while the nitrogen treatments (N) were 0, 100, 200, and 300 kg/ha (No, N100, N200, and N300). Results showed that soil salinity values remained lower than those of electrical conductivity of irrigation water (ECiw) and were the lowest under treatment I100 and the highest with I30 treatment. Relatively low ECe values were also observed under I60 treatment. The highest potato yields for the two years were obtained with I100 treatment. Compared to I100, significant reductions in potato yields were observed under I60 and I30 deficit irrigation treatments resulting from a reduction in tubers number/m2 and tuber weight. The water productivity (WP) was found to significantly vary among treatments, where the highest and the lowest values were observed for I30 and I100 treatments, respectively. Potato yield and WP increased with an increase in nitrogen rates. The rate of 300 kg N/ha was seen to give good yield and higher WP of potato under full (I100) and deficit (I60) irrigation treatments. However, application of N adversely affected potato yield and WP, when N level applied above 200 kg N/ha at I30. The WP was improved by N supply, but its effect decreased as the irrigation level increased. The IWP at I100, which produced the highest potato yield, was 8.5 and 9.9 kg/m3 with N300 but this increased to 11.9 and 15.6 kg/m3 at I30 with N200, in 2010 and 2011, respectively. These results suggested that potato in arid region could be cultivated with acceptable yields while saving irrigation water and reducing nitrogen supply but it was essential to exploit the interaction effect between these two parameters to maximize resource use efficiency.

Research progress on plant tolerance to soil salinity and alkalinity in sorghum

Sorghum is an important source of food, feed and raw material for brewing, and is expected to be a promising bioenergy crop. Sorghum is well known for its strong resistance to abiotic stress and wide adaptability, and salt tolerance is one of its main characteristics. Increasing sorghum planting acreage on saline-alkalien land is one way to effectively use this kind of marginal soil. In this paper, domestic and overseas research on plant tolerance to soil salinity and alkalinity in sorghum, including salt-tolerant genetics and breeding, physiology, cultivation, and identification of tolerant germplasms, are reviewed. Suggestions for further studies on salinity and alkalinity tolerance in sorghum are given, and the prospects for sorghum production in saline-alkalien land are discussed.

Tolerance to Salinity of Sesame Genotypes in Different Phenological Stages

The sesame crop is usually avoided in salt-affected areas because of the various effects of saline stress on plants. Besides varying between species, salinity effects are known to vary for genotypes of the same species as well as plant development stages. Thus, through the irrigation of plants with saline water, this study evaluates tolerance to saline stress of new sesame genotypes in different phenological stages. Three experiments were carried out under greenhouse conditions, using the sesame genotypes BRS Seda, LAG-927561 and LAG-26514. Water with different levels of electrical conductivity (ECw = 0.6, 1.6, 2.6, 3.6 and 4.6 dS m-1) was used to irrigate plants during germination and initial growth stages, as well as the entire crop cycle. Tolerance to saline stress (3.6 dS m-1) during growth and production stages was also studied. Salinity did not affect sesame germination, but seedling growth was hindered from the ECw of 1.6 dS m-1 onwards, and plant height was the most affected growth variable. Seed production is affected by salinity, regardless of the phenological stage in which plants are exposed to salinity. The strains LAG-927561 and LAG-26514 show promising signs in studies on adaptation to saline stress.

Yield Gap of Stress Tolerant Rice Varieties Binadhan-10 &Binadhan-11 in Some Selected Areas of Bangladesh

Binadhan-10 & Binadhan-11 are climate smart stress tolerant high yielding rice varieties (yield > 4 t&#8901;ha&#8722;1) have saline tolerant EC up to 12 ds/m and submergence tolerant up to 20 - 25 days capacity. The present study was an attempt to analyze the yield gap of stress tolerant varieties Binadhan-10 & Binadhan-11 in some selected areas of Bangladesh. The objectives of the study were: 1) to estimate the yield gap of Binadhan-10 &-11 growers among the study areas;2) to identify the factors affecting the yield of these variety;and 3) to suggest some policy guidelines to minimize the yield gap. The study was conducted in eight Binadhan-10 & Binadhan-11 growing areas in Bangladesh. In this study, four districts namely Satkhira, Khulna, Barishal, and Cox’s Bazar were used for Binadhan-10 and Mymensingh, Jamalpur, Sherpur and Sunamgonj were taken for Binadhan-11. It is based on primary level data from eight sub-districts among the study areas. A total of 240 farmers were randomly selected (30 from each location) to collect the data with a pre-designed questionnaire. Farmer were grouped according to saline affected and not-affected for saline tolerant variety Binadhan-10 and not affected, affected (1 - 10 days) and highly affected (10 - 20 days) for submergence tolerant rice variety Binadhan-11 to identify existing yield gap. Tabular as well as Zandstra method were applied for analysis the data. The study also found factors affecting the gap and some policy guidelines to minimize the gap.

盐碱胁迫对水稻生长特性及产量的影响

为了有效利用并改良盐碱地及改善生态环境,以8份水稻种质资源为材料,设置轻度盐碱胁迫、中度盐碱胁迫、重度盐碱胁迫进行田间耐盐碱性分析,对植株存活率、株高、分蘖、叶绿素相对含量、每穗粒数、结实率以及千粒重等指标进行了比较,分析不同程度盐碱胁迫对水稻生长发育特性及产量的影响。结果表明,水稻品种间耐盐碱特性存在差异,水稻存活率表现为轻度盐碱胁迫>中度盐碱胁迫>重度盐碱胁迫,水稻品种从返青期至成熟期植株存活率呈下降趋势。盐碱胁迫导致水稻株高变矮、穗长变短,随着盐碱胁迫程度增加株高和穗长受到的抑制作用变强,同一品种株高和穗长数值表现为轻度盐碱胁迫>中度盐碱胁迫>重度盐碱胁迫,且3种盐碱胁迫处理间差异显著(P<0.05)。齐穗期SPAD值范围为42.5~55.6,各处理与对照间差异不显著。重度盐碱胁迫下水稻产量抑制率高达81.0%~93.7%,中度盐碱胁迫下产量抑制率为10.4%~81.3%,轻度盐碱胁迫下为5.6%~77.9%,产量及产量构成因素相对抑制率主要表现为重度盐碱胁迫>中度盐碱胁迫>轻度盐碱胁迫,盐碱化程度越高对水稻产量及产量构成因素造成的损失也越大。相关分析表明,产量相对抑制率与单位面积穗数相对抑制率极显著相关,与实粒数相对抑制率和结实率相对抑制率正相关。说明,盐碱胁迫抑制水稻生长发育,导致产量降低,但合理开发和利用中度、轻度盐碱化土地可以扩大水稻种植面积。

张掖耐盐碱亚麻品种筛选与示范研究

为筛选生育期适宜、丰产性好、出麻率高、纤维产量高的亚麻品种,高效开发利用张掖盐碱地;以8个亚麻品种为试验材料,以张掖市龙纺麻业提供的山丹为对照,在山丹县位奇镇进行试验;对不同品种原茎产量、种子产量以及其他农艺性状进行田间鉴定;结果表明:8个参试品种的原茎、纤维产量均较当地对照品种山丹大幅度增产,其中华亚5号产量居首,中亚麻3号稍逊,二者原茎较当地对照品种山丹分别增产94.83%和80.85%,达极显著水平;纤维较当地对照品种增产164.74%和147.32%,达极显著水平;华亚5号、中亚麻3号等2个品种(系)在张掖试点综合经济性状、丰产性表现较好,适应性及抗逆性相对较强,可在张掖作为纤维用亚麻品种示范推广.

遮荫对盐胁迫下油葵生长和光合生理的影响

盐碱地光伏系统下作物生长受到盐分和遮荫的双重影响,研究双重逆境下作物的生理响应对该系统内作物种植有重要指导意义。本研究以油葵(Helianthus annuus L.)为试验材料,采用盆栽试验,设3个盐分水平(在初始含盐量的基础上外加NaCl含量0 g·kg^(−1)、3 g·kg^(−1)和5 g·kg^(−1))和4个遮荫水平(0%、30%、60%和90%),探究遮荫对盐胁迫下油葵生长、光合特性、叶片解剖结构、生物量积累和分配及籽粒产量等的影响,为盐碱地光伏系统下开展作物种植提供理论依据。结果表明,不同盐分水平下,与不遮荫(遮荫水平0%)处理相比,遮荫会破坏油葵叶片光合反应中心,降低光能转换效率,减小叶片厚度和栅栏组织层,减少光合产物积累,进而抑制茎粗和花盘的生长,影响光合产物分配方向,最终降低籽粒产量;但适度遮荫下油葵会通过增加株高、增大叶面积、提高核酮糖-1,5-二磷酸羧化酶(Rubisco酶)和磷酸烯醇式丙酮酸羧化酶(PEPC酶)活性等方式提高叶片的光捕获能力,促进光合作用进行。不同遮荫水平下,与无盐分处理相比,轻(3 g·kg^(−1)NaCl)、重(5 g·kg^(−1)NaCl)度盐胁迫均会降低油葵的光合效率,抑制株高、茎粗、花盘和叶片的生长,减少光合产物的积累,最终降低籽粒产量,且不同盐胁迫浓度下油葵生长和光合生理特性在不同遮荫水平的变化规律不一致。其中,30%遮荫水平能显著提高轻度盐胁迫下油葵叶片的Rubisco酶和PEPC酶活性,减小叶片厚度,增大栅栏组织层,提高水分利用效率,进而提高油葵光合效率,促进油葵生长。研究表明弱光环境下油葵会通过改变自身形态、光合酶活性、光合产物分配等方式来应对环境胁迫,且遮荫能在一定程度上缓解盐胁迫对油葵造成的负面影响。其中,30%遮荫水平对缓解轻度盐胁迫引起的油葵光合能力降低和生长抑制的效果较好。

一氧化氮对盐碱胁迫下盐地碱蓬抗逆性及饲用品质的影响

为了探究一氧化氮(nitric oxide,NO)对盐碱胁迫下盐地碱蓬幼苗生长及饲用品质的影响及其作用机制。本研究以盐地碱蓬为材料进行盆栽试验,利用300 mmol·L^(-1) NaCl,NaHCO_(3)和Na_(2)CO_(3)(1∶1)溶液分别模拟盐、碱胁迫,硝普钠(sodium nitroprusside,SNP)和PTIO(carboxy-PTIO)作为NO的供体和清除剂,分析盐碱胁迫下NO对植物生长指标、抗氧化能力、光合特性、离子含量及饲用品质的影响。结果表明:1)盐碱胁迫显著抑制了盐地碱蓬幼苗的生长状况,降低生物量累积、光合效率和K^(+)含量,提高活性氧含量、抗氧化酶活性、Na^(+)含量和Na^(+)/K^(+)。此外,盐碱胁迫导致盐地碱蓬的饲用品质下降,粗蛋白,粗脂肪、干物质含量降低,纤维素类物质含量增加。2)外施NO显著提高了盐地碱蓬的耐盐碱胁迫能力,具体表现为,幼苗通过进一步增强抗氧化物酶活性,减轻盐碱胁迫造成的氧化损伤;通过增加光合色素含量、提高气孔导度、蒸腾速率和净光合速率,缓解盐碱胁迫导致的光合抑制;通过提高K^(+)含量、降低Na^(+)过量积累和Na^(+)/K^(+),重建盐碱胁迫下的离子平衡。3)外施NO有效改善了盐地碱蓬的饲用品质,其粗蛋白、粗脂肪和干物质含量升高,增幅最高可达46.0%,纤维类物质含量显著下降,降幅最高可达32.0%。本研究为后续利用盐地碱蓬进行盐碱土壤改善以及家畜饲用提供了理论依据和研究基础。

盐胁迫对水稻籽粒灌浆特性及产量形成的影响

以江苏沿海滩涂主栽常规粳稻南粳9108和淮稻5号为试材,研究不同盐胁迫处理包括对照(CK,盐浓度0)、中盐(medium-salinity stress,MS,盐浓度0.15%)和高盐(high-salinity stress,HS,盐浓度0.3%)对水稻籽粒灌浆及产量形成生理特性的影响。结果表明:(1)与对照相比,中盐和高盐胁迫均显著降低水稻产量,降幅分别为26.3%和57.7%(两品种平均);盐胁迫处理下,穗数、每穗粒数、结实率和千粒重均显著下降。(2)盐胁迫显著降低穗长、每穗强势粒和弱势粒籽粒数、结实率和千粒重,其中强势粒结实率和千粒重的降幅均低于弱势粒。(3)盐胁迫下,水稻植株抽穗期和成熟期干物重以及抽穗期至成熟期干物质积累量显著下降,但收获指数明显增加。此外,抽穗后15 d和30 d盐胁迫处理的叶片净光合速率和SPAD值均显著低于对照。(4)盐胁迫降低籽粒最大灌浆速率和平均灌浆速率,但达最大灌浆速率时间和有效灌浆天数有所增加;盐胁迫提高了强势粒和弱势粒有效灌浆天数,但平均灌浆速率显著下降,其中强势粒灌浆量的降幅低于弱势粒。(5)盐胁迫下,籽粒腺苷二磷酸焦磷酸化酶(AGPase)、淀粉合成酶(SSS)、颗粒型淀粉合成酶(GBSS)和淀粉分支酶(SBE)活性显著下降,其中弱势粒的降幅高于强势粒。综上所述,盐胁迫下水稻强势粒和弱势粒灌浆天数有所增加,但籽粒灌浆速率及其淀粉合成关键酶活性显著下降,致使籽粒充实度、粒重和产量显著下降,其中盐胁迫对弱势粒抑制作用大于强势粒。

蕨麻响应盐碱胁迫的形态及转录组分析

为研究不同盐碱胁迫对蕨麻生长情况的影响,结合转录组进行测序分析,采用土培法对蕨麻进行不同梯度的NaCl、NaHCO3胁迫处理,分析其株高、茎粗等形态指标对不同浓度盐碱胁迫的响应差异,结合Illumina高通量测序技术进行转录组测序,初步探究盐碱胁迫对其转录水平的影响。结果表明,盐碱胁迫下,蕨麻对盐的耐受能力强于碱,随着胁迫浓度的增高,蕨麻相关农艺性状呈先增加后降低的趋势,整体呈现出“低促高抑”的现象;MDA含量随胁迫浓度的增大呈先升后降的趋势,说明膜脂过氧化明显,且当胁迫浓度超过一定阈值,抗氧化和渗透调节系统均不能缓解其膜系统损伤;转录组测序共产生82.95 Gb Data,各样品Clean Data均达到8.41 Gb及以上,Q 30碱基百分比在93.17%及以上,通过DEGs分析,3个比较组(ck-vs-NaCl、ck-vs-NaHCO3、NaCl-vs-NaHCO3)分别筛选出1 616个、1 590个和1 770个DEGs;GO富集分析结果表明,盐应答、类黄酮生物合成过程、硝酸还原酶(NADPH)等GO Term被显著富集;KEGG分析表明,苯丙烷生物合成、黄酮类化合物生物合成、MAPK信号途径和植物激素信号转导等通路被显著富集;并且在DEGs中鉴定的ERF、MYB、NAC、WRKY、MYB和bZIP转录因子家族成员最多。蕨麻主要通过提高茎粗和减小小叶面积等方式来适应胁迫环境,整体呈现“低促高抑”的规律,其存在一定阈值。蕨麻通过调节膜成分、氧化还原酶活性、类黄酮生物合成过程、苯丙烷生物合成、MAPK信号途径和植物激素信号转导等生物过程和代谢途径,结合有关转录因子对其所处盐碱环境进行响应。

盐、干旱及其复合胁迫对水稻产量和品质形成影响的研究进展

滨海盐碱地水稻生产受限于淡水资源和水利基础设施,盐害和干旱往往交织出现,极易遭受盐−旱复合胁迫,严重制约了滨海盐碱地水稻丰产优质目标的实现。全面剖析盐、干旱胁迫及其复合胁迫对水稻产量和品质形成的影响及其生理机制,可为滨海盐碱地水稻高产与品质调优栽培提供科学支撑。本文概述了盐、干旱及其复合胁迫对水稻生长发育、产量形成和稻米品质的影响,从渗透调节、离子平衡、光合作用、抗氧化酶系统、内源激素、蔗糖-淀粉代谢关键酶活性和分子机制等方面阐述其影响水稻产量和品质形成的作用机制,从耐盐耐旱品种选育及栽培调控等方面提出了减轻水稻盐/干旱胁迫的调控措施,为今后深入开展水稻耐盐和干旱的研究提出建议。

芥菜对盐胁迫的响应机制研究进展

芥菜是我国的特色蔬菜之一,在我国种植范围广,易管理,产量高,是盐碱地改良及利用的优良作物之一。为了促进盐碱地改良,从芥菜种质资源筛选与鉴定、对盐胁迫的响应机制及提高耐盐性的途径等方面总结了近年来关于芥菜耐盐胁迫的相关研究成果,其中,种质资源筛选与鉴定包括目前发现的强耐盐品种及基因型,对盐胁迫的响应机制研究包括盐胁迫对芥菜的生长发育、光合作用、生理指标及相关基因的影响,提高耐盐性的途径包括施用植物生长调节剂或外源物质缓解盐胁迫;并提出了叶用芥菜耐盐性的未来研究方向,即研发适用的植物生长调节剂或外源物质、培育耐盐芥菜品种等,为叶用芥菜耐盐品种的选育与利用提供了理论依据。

水稻产量形成对盐-旱复合胁迫的响应与生理机制

以江苏沿海地区广泛种植的常规粳稻南粳9108和淮稻5号为试材,设计盆栽试验,在0.3%土壤含盐量下,于拔节期至抽穗期设置干旱胁迫(土壤水势-25 kPa),并以无盐、无干旱胁迫为对照,研究水稻产量形成对盐-旱复合胁迫的响应特征。结果表明:与对照相比,单一盐胁迫、单一干旱胁迫和盐-旱复合胁迫下水稻产量(两品种平均)分别下降114.8%、39.6%和154.2%。盐-旱复合胁迫下水稻产量(两品种平均),较单一盐胁迫和单一干旱胁迫分别显著下降18.6%和82.2%。与单一盐胁迫和单一干旱胁迫相比,盐-旱复合胁迫下水稻产量降低主要为每穗粒数、结实率和千粒重的显著下降。与对照相比,单一盐胁迫、单一干旱胁迫和盐-旱复合胁迫均显著降低植株抽穗期和成熟期干物重、拔节后20 d和抽穗后20 d叶片净光合速率与叶绿素(a+b)含量,收获指数有所增加。盐-旱复合胁迫下植株抽穗期和成熟期干物重、拔节后20 d和抽穗后20 d叶片净光合速率与叶绿素(a+b)含量均显著低于单一盐胁迫和单一干旱胁迫;收获指数则呈相反趋势。单一盐胁迫、单一干旱胁迫和盐-旱复合胁迫下水稻拔节后20 d和抽穗后20 d叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性均显著低于对照;叶片丙二醛(MDA)和过氧化氢(H_(2)O_(2))含量则呈相反趋势。与单一盐胁迫和单一干旱胁迫相比,盐-旱复合胁迫下拔节后20 d和抽穗后20 d叶片SOD、CAT和APX活性显著下降,MDA和H_(2)O_(2)含量则显著增加。这说明,与单一盐胁迫和单一干旱胁迫相比,盐-旱复合胁迫显著抑制水稻植株光合性能,从而影响光合同化物的积累与分配,最终导致库容量与充实效率以及水稻产量的显著下降。盐-旱复合胁迫造成水稻产量的降幅显著高于单一盐胁迫和单一干旱胁迫,其对水稻产量的抑制效应具有叠加效应。

不同品种荷花耐盐碱性评价及鉴定指标筛选

为研究不同荷花(Nelumbo nucifera)品种在混合盐碱胁迫下的耐受程度,筛选抗性品种,采用盆栽法,以20个荷花品种为试验材料,对其进行100 mmol·L^(-1)(NaCl∶NaHCO3=2∶1)混合盐碱胁迫处理,7 d后测量株高、叶面积、光合色素、叶绿素荧光参数、丙二醛含量、抗氧化物酶活性及渗透调节物质含量,通过耐盐碱系数、相关性分析、主成分分析、隶属函数法、聚类分析等方法对20种荷花耐盐碱性进行综合评价。结果表明:不同荷花品种单项指标的耐盐碱系数变异系数差异较大,除超氧化物歧化酶活性和过氧化物酶活性外,其余单项指标的耐盐碱系数均存在显著或极显著相关性,利用主成分分析将12个单项指标转换为5个综合指标,各综合指标贡献率分别为36.175%、18.709%、13.470%、11.379%、6.610%,累计贡献率达到86.344%。以耐盐碱性综合评价值(D值)为依据进行聚类分析,将20个荷花品种分为4类,第一类为强耐盐碱型,共计4个荷花品种,第二类为耐盐碱型,共计5个荷花品种,第三类为不耐盐碱型,共计8个荷花品种,第四类为敏感型,共计3个荷花品种。通过逐步回归分析建立荷花的耐盐碱性最优评价模型,D=0.453+0.148X_(1)+0.122X_(2)-0.122X_(7)-0.033X_(8)+0.093X_(11)+0.037X_(12)(R^(2)=0.992),估计精度95.45%以上,并筛选出株高、叶面积、丙二醛含量、脯氨酸含量、可溶性糖含量和可溶性蛋白含量为荷花耐盐碱性评价指标,可以在相同的条件下,通过测定这6项指标,确定荷花的耐盐碱性强弱。

硅素穗肥优化滨海盐碱地水稻矿质元素吸收分配提高耐盐性

本研究旨在阐明硅素穗肥调控盐碱地水稻抽穗期矿质元素分配的作用机制。以常规粳稻淮稻5号为材料,于2019年和2020年在江苏沿海大丰盐碱地(盐分3.4 g kg^(–1),p H 8.3)开展大田试验,设置3个硅肥用量(0、60和100 kg hm^(–2)),于幼穗分化期随穗肥施入。结果表明:(1)硅素穗肥促进抽穗期植株养分吸收,提高成熟期干物质量和产量,与Si0相比,Si60平均增产4.3%,Si100平均增产8.6%;(2)硅素穗肥优化了水稻不同部位K^(+)、Na^(+)分配,提高水稻叶片、上部叶鞘、中下部茎秆K^(+)含量,降低穗、上部叶片、叶鞘、茎秆Na^(+)含量,提高各部位的K^(+)/Na^(+),进而提高离子稳态;(3)硅素穗肥促进叶片大量元素N、P、Ca、Mg和微量元素Fe、Mn的积累,与Si0相比,硅素穗肥显著提高了16.5%的P含量、18.5%的Mg含量、22.4%的Ca含量、19.8%的Fe含量,缓解盐碱胁迫对水稻叶片的不利影响。综上所述,硅素穗肥优化了盐碱胁迫下水稻矿质元素的吸收分配,减轻幼嫩器官盐胁迫程度,促进叶片多种有益元素积累,促进水稻养分吸收,且100 kg hm^(–2)效果最佳。

金丝楸幼苗响应盐碱胁迫的生理和转录组分析

[目的]研究不同盐碱胁迫对金丝楸幼苗生长、光合和生理指标的影响,并结合转录组测序分析,探究楸树耐盐碱的生理机制和分子机制。[方法]采用盆栽法对金丝楸幼苗进行不同盐碱胁迫处理,分析其生物量、光合及生理指标对不同盐碱响应的差异,采用Illumina高通量测序技术进行转录组测序,通过生物信息学分析盐碱胁迫对转录水平的影响。[结果]不同盐碱胁迫下,金丝楸幼苗叶片受伤害程度为Na_(2)CO_(3)>混合盐碱>NaCl;新增株高和地径、地上部和根的干质量和鲜质量、生物量、根冠比均受到明显抑制,并随盐碱浓度增加而抑制加强,但生长胁迫指数均随浓度的增加而降低;丙二醛(MDA)含量和相对电导率都随胁迫浓度增加而不同程度上升,超氧化物歧化酶(SOD)活性、可溶性糖含量、脯氨酸(Pro)含量、叶绿素总量和光合速率都呈现先上升后下降的趋势。转录组测序共产生约60.4 Gb原始数据,组装得到55793个Unigenes,其中29534(52.93%)个Unigenes获得了注释;通过差异表达基因(DEGs)分析,3个比较组(CK vs NaCl,CK vs Na_(2)CO_(3)和CK vs混合盐碱)分别筛选出1779、2835和4059个DEGs;DEGs GO富集分析表明,膜的整体成分、膜的内在成分、催化活性、类异戊二烯代谢和合成过程、氧化还原酶活性等条目被显著富集;DEGs KEGG分析表明,苯丙素生物合成、淀粉和蔗糖代谢、植物激素信号转导、萜类主干生物合成和精氨酸代谢等通路被显著富集;此外,在DEGs中鉴定的bHLH、ERF、MYB-related、NAC、C2H2、WRKY、MYB和b ZIP转录因子家族成员最多。[结论]金丝楸主要通过积累可溶性糖和Pro,提高SOD酶活和光合作用来抵御盐碱胁迫,但都呈现“低促高抑”的现象,说明其具有一定阈值。金丝楸通过调节膜成分、催化活性、类异戊二烯代谢和生物合成过程、苯丙素生物合成、淀粉和蔗糖代谢、植物激素信号转导等生物过程和代谢途径,并结合有关转录因子共同响应盐碱胁迫。本研究为深入研究楸树耐盐碱生理机制和分子机制提供科学的理论依据。

外源CaCl_(2)缓解东京四照花幼苗盐胁迫的生理机制

以东京四照花(Cornus hongkongensis subsp.tonkinensis)幼苗为试验材料,考察施用外源CaCl_(2)对3‰海盐处理条件下东京四照花幼苗生长、光合色素含量、光合气体交换参数、渗透调节物质含量等生理指标的变化特征,探讨外源CaCl_(2)对盐胁迫伤害的缓解效果及生理机制。结果表明:(1)3‰海盐胁迫处理下,东京四照花幼苗生长受到显著抑制,其叶片丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性以及渗透调节物质可溶性糖、可溶性蛋白及脯氨酸的含量均显著增加,而叶片光合色素含量、胞间二氧化碳浓度(C_(i))、净光合速率(P_(n))、气孔导度(G_(s))和蒸腾速率(T_(r))显著降低。(2)3‰海盐和CaCl_(2)复合处理下,施用低浓度(10~20 mmol·L^(-1))外源CaCl_(2)降低了幼苗的盐害率和死亡率,促进了幼苗的叶片和植株生物量积累,但降低了可溶性蛋白含量;中低浓度外源CaCl_(2)均显著降低了幼苗叶片的MDA含量与SOD活性,而施用中浓度(30 mmol·L^(-1))外源CaCl_(2)则提高了幼苗叶片叶绿素b和总光合色素的含量;所有浓度的外源CaCl_(2)处理均有效增强了幼苗叶片C_(i)、P_(n)、G_(s)和T_(r),但低浓度处理的效果显著优于中高浓度处理;高浓度CaCl_(2)(40 mmol·L^(-1))对盐胁迫幼苗的各项生理指标均未产生有效的缓解作用。研究发现,适宜浓度(10~20 mmol·L^(-1))外源CaCl_(2)可以通过减少光合色素的分解,提高光合速率,抑制活性氧的积累,维持质膜稳定性来降低盐胁迫的伤害,从而降低幼苗的盐害率和死亡率,有效缓解盐胁迫对东京四照花的抑制作用。

煤矸石改良盐碱土对马铃薯生长的影响

为探索煤矸石用于盐碱地改良的可行性,拓展大宗固体废物煤矸石的资源化利用途径,该研究采用盆栽法对煤矸石用量影响盐碱土理化性质及马铃薯生长进行研究。试验设置4个处理:85%盐碱土+15%煤矸石(CL15)、70%盐碱土+30%煤矸石(CL30)、50%盐碱土+50%煤矸石(CL50),以及不添加煤矸石的对照(CK),分析煤矸石用量对土壤理化性质、马铃薯植株生长生理、产量和品质等的影响。结果表明:1)煤矸石加入能够影响土壤的理化性质,改善盐碱土自身贫瘠、板结的土质,土壤pH值、盐分浓度、容重逐渐降低,土壤结构趋于稳定,同时土壤中有机质、全氮、全磷、全钾、水解氮和速效钾含量显著增加(P<0.05),增幅分别为15.2%~447.2%、11.7%~27.6%、0.5%~29.5%、43.3%~225.8%、16.6%~216.1%和3.6%~34.9%。2)不同煤矸石添加量对马铃薯植株生长、光合作用以及抗逆性等指标影响效果存在差异,随着煤矸石用量的增加,植株各个时期的生长生理、抗逆境胁迫等指标多数呈现先增加后降低的趋势。CL30处理对马铃薯生长促进效果最佳,CL50则表现出一定的抑制作用,3个品种马铃薯收获后的地上生物量排序均为CL30、CL50、CL15。3)对照中马铃薯植株在幼苗期全部死亡,煤矸石各处理种植马铃薯可完成生长周期并结薯。CL30处理下单株块茎质量最高,为252.37~424.10 g/株,块茎中淀粉、蛋白质和维生素C含量也最高,分别为90.0~110.3 g/kg、13.3~14.1 g/kg和99.0~164.0 mg/kg,但与商品马铃薯品质相比仍有差距,淀粉、蛋白质和维生素C含量分别低于商品马铃薯21.2%~35.7%、45.8%~48.8%和7.9%~44.4%。综上所述,煤矸石可用于盐碱土改良,煤矸石用量为30%时,可有效改善盐碱土壤环境并适合种植马铃薯,因而在盐碱地土壤改良、保障粮食安全领域具有应用前景。

干旱对不同马铃薯品种生长和产量的影响

【目的】明确干旱环境对不同马铃薯品种生长和产量的影响,并评价抗旱性。【方法】对8个马铃薯品种进行正常灌水和干旱胁迫处理,测定株高、茎粗、叶面积指数、叶绿素含量(SPAD值)、干物质积累量、根冠比和产量,利用主成分分析和隶属函数法计算综合抗旱度量值(D),并对不同马铃薯品种的抗旱性进行综合评价。【结果】干旱胁迫处理下,不同马铃薯品种株高、茎粗、叶面积指数和产量较正常灌水处理有所降低、SPAD值有所上升;大丰10号和希森6号的各项指标与正常灌水处理差异不显著或降幅较小,鲁引1号、大丰9号和冀张薯12号的各项指标均显著低于正常灌水处理。干旱胁迫处理下,不同品种间植株各指标差异明显,希森6号株高和茎粗表现最佳,分别为64.20 cm和12.63 mm;鲁引1号株高最低,为49.53 cm;冀张薯12号茎粗最小,为10.13 mm;华颂7号SPAD值最高,为53.03;冀张薯12号SPAD值最小,为39.73。干旱胁迫处理下,大丰10号在叶面积指数、干物质积累量、根冠比和产量方面表现最佳,分别为1.88、170.80 g/株、0.12、34750 kg/hm^(2);冀张薯12号的叶面积指数、根冠比和产量表现最差,分别为0.94、0.08、18750 kg/hm^(2);大丰9号干物质积累量最小,为121.78 g/株。干旱胁迫处理下,大丰10号和希森6号抗旱指数较高,分别为0.986和0.756。对各项指标进行主成分分析,共得到2个主成分:第1主成分贡献率为57.807%,特征值为5.203;第2主成分贡献率为20.281%,特征值为1.825。干旱胁迫处理下,大丰10号的综合抗旱度量值最大,为1.000。【结论】根据干旱胁迫处理下不同马铃薯品种生长和产量表现以及综合抗旱度量值大小,大丰10号抗旱性较强。