Quinoa (Chenopodium quinoa Willd.) is capable of adapting to multiple environments and tolerating abiotic stresses including saline, drought and frost stress conditions. However, the introduction of quinoa into new environments has disclosed adaptation challenges. The principle factor affecting crop pollination is heat stress at flowering, which leads to sterile plants. To investigate the effect of high temperatures during the sensitive phenological phases, flowering and seed germination, a Danish-bred cultivar (cv. Titicaca) was grown in climatic chambers. Selection of the cv. Titicaca was based on the fact that it is the most extensively used cultivar in the Sahel and Middle East and North African region. The results of this research demonstrated that temperatures exceeding 38 °C hindered seed germination and pollination, and therefore, seed yield at harvest. At 38 °C, seed yield losses were 30%, whilst seed germination percentage declined below 50%. In addition, the results of the present research were compared with field observations from Burkina Faso in order to determine the spatiotemporal suitability of this crop with respect to temperature stress. Although many other abiotic stresses need to be considered when defining crop calendars (e.g. heavy precipitation in July and August), this research proposes the following growing periods to avoid heat-stress conditions at flowering: Sahel (July–September and November–February), Soudano–Sahel (June–February) and Soudanian zone (all year round).

水分和氮素是影响水稻生长发育的两个重要环境因子。适宜的水氮耦合模式可通过“以水调氮、以水控氧”调控稻田根际氮形态和溶氧量等环境因子,促进良好根系形态构建,提高叶片光合速率和光合产物“源-库”分配平衡,提高水稻群体质量和产量形成。同时,稻田水氮氧环境因子驱动的微生物调控机制在水稻-土壤系统氮高效利用方面也发挥重要作用。本文重点阐述了水氮耦合下水分、氮形态和溶氧量对水稻生长发育、光合作用、碳氮代谢、稻田氮转化过程及其微生物调控机制等方面的研究进展,展望并提出了未来亟待加强的研究方向:1)开展水氮耦合下水稻根际溶氧量时空动态分布特征及氧环境调控关键因子研究;2)明确不同基因型水稻根源信号增氧响应特征及其对水稻生长发育的影响调控机制;3)阐明根际氧环境驱动的关键微生物过程对稻田氮转化和氮素利用的影响。

【目的】研究与评价PEG模拟干旱胁迫下10个藜麦品种的萌芽期抗旱性。【方法】采用5%~30%不同浓度PEG-6000溶液模拟干旱胁迫条件。【结果】低浓度PEG-6000对藜麦种子萌发及根长具有促进作用,对茎长有一定的抑制作用。随着PEG-6000浓度增大,所有抗旱指标均下降。【结论】利用隶属函数分析得出,10个藜麦品种萌发期抗旱性强弱顺序为:YL2＞YL1＞YL7＞YL3＞YL9＞YL5＞YL10＞YL6＞YL8＞YL4。为较好的反映藜麦品种在不同胁迫程度的耐受能力,将10个藜麦品种划分为三个抗旱级别:YL1、YL2、YL7为强耐旱品种; YL3、YL9为中等耐旱品种;YL4、YL5、YL6、YL8、YL10为弱耐旱品种。

Although peroxisomes play a key role in plant metabolism under both normal and stressful growth conditions, the impact of drought and heat stress on the peroxisomes remains unknown. Quinoa represents an informative system for dissecting the impact of abiotic stress on peroxisome proliferation because it is adapted to marginal environments. Here we determined the correlation of peroxisome abundance with physiological responses and yield under heat, drought and heat plus drought stresses in eight genotypes of quinoa. We found that all stresses caused a reduction in stomatal conductance and yield. Furthermore, H O content increased under drought and heat plus drought. Principal component analysis demonstrated that peroxisome abundance correlated positively with H O content in leaves and correlated negatively with yield. Pearson correlation coefficient for yield and peroxisome abundance (r = -0.59) was higher than for commonly used photosynthetic efficiency (r = 0.23), but comparable to those for classical stress indicators such as soil moisture content (r = 0.51) or stomatal conductance (r = 0.62). Our work established peroxisome abundance as a cellular sensor for measuring responses to heat and drought stress in the genetically diverse populations. As heat waves threaten agricultural productivity in arid climates, our findings will facilitate identification of genetic markers for improving yield of crops under extreme weather patterns.© 2019 The Authors The Plant Journal © 2019 John Wiley & Sons Ltd.

针对西北盐碱地区栽培土壤资源有限问题，研究混合盐碱胁迫对醉马草种子萌发及幼苗生理相关酶特性的影响，旨在探讨与揭示醉马草对盐碱土壤环境的适应机制，为西北盐碱地区的耐盐草种的选育及栽培提供理论基础。为模拟西北地区复杂的盐碱环境，本研究将中性盐（NaCl、Na₂SO₄）和碱性盐（NaHCO₃、Na₂CO₃）按不同比例混合（A： NaCl∶Na₂SO₄=1∶1； B： NaCl∶Na₂SO₄∶ NaHCO₃=1∶2∶1； C： NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=1∶9∶9∶1； D： NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=1∶1∶1∶1； E： NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=9∶1∶1∶9），并设置50、100、150、200 mmol·L^-14个盐浓度梯度对带菌（E+）和不带菌（E-）醉马草种子萌发和幼苗生长阶段进行胁迫，分析盐胁迫下醉马草种子萌发阶段的发芽率、发芽势、发芽指数、活力指数、平均发芽时间及幼苗生长阶段的苗长、胚根长度、根冠比、抗氧化酶（POD、SOD、CAT）活性、丙二醛 （MDA）和脯氨酸（proline）含量。并通过隶属函数和主成分分析对不同盐胁迫下的醉马草耐盐性进行综合评价。结果表明：5种盐碱胁迫均使醉马草发芽率、发芽势、发芽指数、活力指数降低及平均发芽时间延长，且随盐浓度的增加，种子萌发受到显著抑制（P<0.05）；盐碱胁迫亦随盐浓度的增加使醉马草胚根长度、根冠比显著降低。除C、E处理外，其余混合盐碱胁迫下的醉马草幼苗生理指标（POD、SOD、MDA、proline）均随盐浓度的上升而下降。隶属函数和主成分分析显示不同混合盐碱胁迫下的醉马草耐盐性大小顺序为A>D>B>C>E。综上可知，盐碱胁迫显著抑制醉马草种子萌发和幼苗生长（P<0.05），其中碱性盐（NaHCO₃、Na₂CO₃），尤以Na₂CO₃对醉马草种子萌发和幼苗生长抑制作用强于中性盐。活力指数、胚根长度、POD、SOD、proline为评价醉马草耐盐性的主要指标。E+醉马草耐盐性优于E-，内生真菌可有效提高醉马草渗透调节和活性氧清除能力，降低膜脂过氧化作用，提高醉马草耐盐性。

Most assays for superoxide dismutase depend upon competition between the enzyme and some indicating scavenger for O-2. We have investigated the effects of experimental variables on assays based upon the use of either ferricytochrome c or nitro blue tetrazolium. Our results should help investigators to avoid the numerous potential pitfalls which necessarily surround these assay methods.

通过对牧草生长的水分条件进行系统分析，筛选出适合干旱地区的优质抗旱牧草，本研究以5种多年生豆科牧草（草木樨状黄芪、牛枝子、达乌里胡枝子、小冠花、鹰嘴紫云英）为研究对象，测定土壤水分、牧草农艺性状（绿叶数与株高），利用均方根偏差（RMSD）计算绿叶数和株高离散度与土壤水分离散度，并计算两者间的权衡关系，以土壤水分为自变量，权衡值为因变量，利用分位数模型界定维持植物正常生命活动的土壤水分阈值，同时结合干旱胁迫下牧草生理指标，达到科学评价牧草抗旱性的目的，结果表明：1）胁迫前期牧草农艺性状优于对照，随胁迫时间延长，牧草农艺性状大体呈下降趋势；2）土壤水分阈值（绿叶数）分别为草木樨状黄芪（17%）、牛枝子（10%）、鹰嘴紫云英（5%），土壤水分阈值（株高）分别为草木樨状黄芪（16%）、牛枝子（14%）、鹰嘴紫云英（10%）；3）以隶属函数法对7项生理指标进行综合评价，5种多年生豆科牧草抗旱性强弱表现为：牛枝子>达乌里胡枝子>小冠花>鹰嘴紫云英>草木樨状黄芪；4）综合牧草外部性状与内部生理评价，选出可耐受中度干旱地区的牧草为牛枝子，可作为中度干旱区的引种牧草。

干旱是制约甘蔗产业发展的重要因素之一。前人研究表明, 斑茅具有良好的抗性基因, 可以通过远缘杂交遗传给后代。本研究以斑茅与甘蔗杂交F₁代无性系YCE96-40为材料, 对苗期干旱处理0 h和24 h后的叶和根进行转录组测序分析, 比较了根和叶在转录水平上响应干旱的差异, 鉴定出21,885个(DR vs CR:10176, DL vs CL:7907)差异表达基因(DEGs), 根中差异表达基因多于叶中, 说明根对干旱胁迫响应更为剧烈。GO功能富集分析发现, 根和叶中DEGs均富集到与脱水反应相关及激素信号转导过程相关的条目, 比如“对渗透胁迫生物过程的响应”和“对缺水生物过程的反应”等。与叶不同的是, 根中大量DEGs显著富集到与细胞膜相关的条目。在根中鉴定出多个木质素相关DEGs, 表明木质素参与了根的干旱响应。通过对所有DEGs进行WGCNA分析, 共鉴定出11个基因共表达模块, 其中与干旱处理后的根显著相关有5个模块, 与干旱处理后的叶显著相关的有2个模块。进一步筛选出了26个转录因子为甘蔗干旱响应的候选转录因子, 构建了调控网络。研究结果为进一步理解甘蔗抗旱性的分子机制及甘蔗抗旱性育种提供了理论指导。

【目的】研究冬小麦光合特性、干物质积累和产量对干旱胁迫的响应,为冬小麦春季灌溉制度提供基础理论依据。【方法】采用盆栽试验,以冬小麦品种邯麦17号为材料,在拔节期设置充分灌水(CK)、轻度干旱(T₁)、中度干旱(T₂)和重度干旱(T₃)4个处理。【结果】拔节期冬小麦叶片水分利用效率在T₂处理下最高;净光合速率、蒸腾速率、气孔导度、胞间二氧化碳浓度和叶绿素含量随着干旱胁迫的加剧均有所降低。光系统Ⅱ(PSⅡ)最大光化学效率(Fv/Fm) 、PSⅡ 的潜在活性(Fv/Fo)和经过PSⅡ的电子传递速率(Fm/Fo)均表现为T₁ > CK > T₂ >T₃。与CK相比,T₁和T₂处理地下部分干物质积累量分别提高11.8%和3.0%,T₃处理降低4.0%;T₁、T₂和T₃处理地下部分干物质占比分别提高4.0%、6.0%和11.0%。灌溉水利用效率在T₁处理下最高,且籽粒产量略有增加,T₂和T₃处理籽粒产量则分别降低14.8%和42.4%(P<0.05)。叶片水分利用效率与地上部干物质积累量呈极显著正相关关系(P<0.01),与总干物质积累量、籽粒产量和灌溉水利用效率呈显著正相关关系(P<0.05),与胞间二氧化碳浓度呈极显著负相关关系(P<0.01)。【结论】轻度干旱处理下,拔节期冬小麦通过调节光合作用和增加地下部分干物质积累量及其占比以适应干旱环境,并提高籽粒产量和灌溉水利用效率;但随着干旱加剧,冬小麦光合速率明显降低,影响干物质积累,导致冬小麦产量降低。

花期前后干旱是影响黄淮海地区夏玉米产量下降的重要因素之一。于2020—2021年开展池栽控制性试验, 以中科玉505为试验材料, 在开花前后28 d内设置4个水分梯度, 包括100%作物蒸散量ET_C (CK)、70% ET_C (干旱胁迫WD1)、40% ET_C (WD2)和0 ET_C (WD3), 研究花期前后干旱胁迫对夏玉米复水后的光合特性、干物质积累与分配以及产量的影响。结果表明: 干旱胁迫处理复水后夏玉米光合性能没有恢复, 表现为叶片SPAD值、净光合速率和群体叶面积指数、光合势、净同化速率低于对照, 植株干物质积累因此受阻, 导致籽粒库容能力下降。干旱胁迫处理使开花吐丝间隔期延长1~3 d, 籽粒败育率增加, 行粒数和百粒重降低, 尤其是WD3的败育率在2020—2021年分别显著增加220.71%和100.73%, WD1、WD2和WD3的产量在2020—2021年分别减产14.52%、36.69%、39.83%和19.62%、45.18%、54.42%。综上所述, 花期前后干旱胁迫在复水后, 玉米的光合性能仍受到抑制, 进而影响光合同化物的积累与分配, 最终导致库容量和产量显著下降。

The extract, fractions, and compounds of the Bouvardia ternifolia root were evaluated as an antiarthritic using a complete Freund’s adjuvant (CFA) model in mice and NF-κB inhibition in RAW 264.7 macrophages. Four active compounds, including two new compounds, ternifoliol and ternifolial, were isolated by open column chromatography and identified by spectroscopic and spectrometric techniques, resulting in benzochromone-like structures with aromatic rings and hydroxyl groups, which could be responsible for the anti-inflammatory activity and inhibitory NF-κB. Changes in the joint cytokine profile monitored the antiarthritic effect. A decrement was observed in the local concentration of the following cytokines with different treatments: IL-17 by 64% and 70.3% with the aqueous extract (BtAq), ethyl acetate extract (BtAcOEt), and M3 fraction; interleukin-1 beta (IL-1β) by 10.2% and 15.7% with BtAq and the M4 fraction, respectively; IL-6 with M1, M2, M3, and M4 between 42% and 64%; necrosis factor-alpha (TNF-α) by 60.9% with M4. Conversely, the anti-inflammatory cytokine interleukin-10 (IL-10) increased between 94% and 99% with M1, M2, M3, and M4. Kidney IL-6 decreased with BtAq, M1, M2, M3, and M4 between 68.9% and 85.8%. TNF-α decreased with BtAcOEt, BtAq, M1, M2, and M4 between 34% and 80.2%. The NF-κB pathway was inhibited with BtAcOEt (90.1%), M1 (85%), M2 (93.5%), M3 (84.5%), M4 (90.3%), ternifoliol (75.6%), bouvardin (20.4%), and scopoletin (89%). We conclude that B. ternifolia modulated the inflammatory response at the joint and kidney levels and the NF-κB pathway.

干旱是制约植物生长的重要胁迫因素之一，目前对于不同性别野牛草抗旱的生理及分子差异机制的研究较少，为探究干旱胁迫下野牛草雌、雄株抗氧化酶活性以及基因表达差异，以野牛草“Texoka”品种为试验材料，测定干旱第0、7、14天以及复水7 d后野牛草雌、雄株叶片相对含水量（RWC）、叶绿素含量（Chl）、PSII最大光化学量子效率（F_v/F_m）以及抗氧化酶活性，利用qRT-PCR技术研究了野牛草雌、雄株抗氧化酶基因在不同干旱时间下的表达差异。结果表明，干旱胁迫下野牛草雌、雄株坪观质量随着干旱时间的延长而降低，复水后恢复，且雌株坪观质量强于雄株。野牛草雌、雄株RWC都随着干旱处理时间增加而下降，复水后恢复，在干旱第7天雌株RWC高于雄株。野牛草雌、雄株Chl含量随着干旱-复水处理都呈下降趋势；F_v/F_m在干旱-复水处理过程中呈相同的趋势，在干旱第14天均显著降低。雌、雄株Chl和F_v/F_m除第7天外均没有显著差异，两者在长期干旱胁迫以及复水后光合特性相似。野牛草雌株超氧化物歧化酶（SOD）活性在干旱第7、14天以及复水7 d后都高于雄株，雌株抗坏血酸过氧化物酶（APX）活性变化更加明显，证明野牛草雌株应对干旱胁迫时APX更快积累；在干旱胁迫下雌、雄株过氧化物酶（POD）活性变化一致，两者没有显著差异。干旱第7天后，野牛草雌、雄株过氧化氢酶（CAT）活性变化趋势完全相反。实时荧光定量PCR分析表明，野牛草雌株抗氧化酶基因表达量在复水后达到峰值，与抗氧化酶活性变化并不一致；雄株FeSOD、Zn/Cu-SOD、POD相对表达量在干旱第14天达到峰值，与抗氧化酶活性变化相同。雄株APX以及CAT相对表达量在干旱第0天最高后下降，复水后上升，与抗氧化酶活性变化不一致。总体而言，野牛草雌、雄株之间在生理及分子水平上对干旱胁迫的响应存在一定差异，且野牛草雌株抗旱性强于雄株。本研究丰富了野牛草抗氧化系统响应干旱胁迫的认识，并为研究雌雄异株植物的抗旱机制提供了参考。