Glycine betaine counteracts the inhibitory effects of waterlogging on growth,photosynthetic pigments,oxidative defence system,nutrient composition,and fruit quality in tomato

Glycine betaine (GB) is an important organic compound mediating plant responses to environmental stresses. However, despite ample research on this biomolecule, the potential of GB in mitigating the effects of waterlogging in plants has not been established. Therefore, we studied the influence of GB on growth and physiology of tomato plants under waterlogged conditions. Waterlogging reduced plant growth, degraded chlorophyll, and increased concentration of malondialdehyde and hydrogen peroxide that deteriorated membrane integrity. Waterlogging increased catalase and peroxidase activities. Waterlogging increased the concentration of Na and reduced concentrations of K. Reductions in root Ca were also recorded. GB enhanced growth, concentration of chlorophyll and activities of superoxide dismutase, catalase, and peroxidase that in turn protected the plants from oxidative damage. GB decreased Na while increasing leaf and root K and stem and fruit Ca under waterlogging. Waterlogging reduced fruit quality. There was decrease in protein, fat, and total dissolved solids and an increase in fruit moisture, P, and Na in plants under waterlogging. GB enhanced fruit quality largely by improving fruit protein, ash, fat, TDS, and Ca, while it decreased fruit Na. The results of this study suggest the use of GB for commercial production of tomato where waterlogging is likely.     

淹水对甜樱桃根系呼吸和糖酵解末端产物的影响

 以美早/东北山樱桃(Prunus serrulata G.Don)和美早/马哈利(P. mahaleb L.)为试材,研究淹水过程中褐色木质根呼吸速率和糖酵解末端产物的变化。结果显示,淹水过程中,两种砧木根系呼吸速率呈下降趋势,胁迫至120 h时,东北山樱桃和马哈利的根系呼吸速率分别为淹水前的73.86％和80.71％;二者根系中乙醛和乙醇含量均呈升高趋势,马哈利乙醛含量高于东北山樱桃,而乙醇含量相反;东北山樱桃丙酮酸含量先升后降,马哈利变幅较小;两种砧木乳酸和琥珀酸含量均呈先升后降趋势,东北山樱桃乳酸、琥珀酸含量出现峰值早且含量大于马哈利;苹果酸含量均呈下降趋势,东北山樱桃下降幅度大于马哈利;二者根系中丙氨酸含量均显著升高,马哈利升幅大于东北山樱桃;天冬氨酸和谷氨酸含量皆下降,其中马哈利下降幅度大于东北山樱桃;脯氨酸含量均先升后降,马哈利的峰值延迟且含量更高。两种砧木对淹水胁迫反应存在差异,东北山樱桃呼吸速率下降较快、细胞碱化能力弱,表明其对淹水更敏感。     

蕾期涝渍胁迫对盆栽棉花生长和产量特性的影响

涝渍灾害是棉花生产中面临的重要自然灾害之一,长江流域棉花蕾期常遭遇多雨天气而产生涝渍灾害。在盆栽条件下,以华棉3109为试验材料,研究了不同涝害胁迫7 d(T1处理)和14 d(T2处理)对棉花生长和产量特性的影响,正常灌水管理作为对照(CK)。结果表明,在涝渍胁迫处理期间,棉花叶片SPAD值、株高、绿叶数、倒四叶功能叶叶面积、开花数、蕾数、结铃数、果枝数和果节数均表现为:CKT1处理T2处理。在处理结束之后(花铃期),受涝渍胁迫棉株株高、茎粗、蕾数、开花数、结铃数、果枝数和果节数等指标都相继出现快速补偿性生长现象。但是随着涝渍胁迫时间的增加,棉花蕾铃脱落率升高,成铃率下降,最终产量构成因素和单株籽棉产量呈下降趋势。     

Phenotypic variation in root development of 162 soybean accessions under hypoxia condition at the seedling stage

Soybean is often damaged by hypoxia caused by waterlogging at the seedling stage. Hypoxia severely inhibits root development and retards plant growth. We aimed to clarify phenotypic variation in root development under hypoxia condition at the seedling stage using diverse soybean accessions. Root development in 162 accessions was evaluated in hydroponic culture. Substantial changes under hypoxia were investigated by means of WinRHIZO analysis before and after the treatment. We found significant phenotypic variation in hypoxia tolerance in root among the 162 accessions. A principal components analysis indicated an association between hypoxia tolerance and the country of origin. We found three new accessions which have a high ability to develop roots under hypoxia (Kokubu 7, Maetsue zairai 90B, and Yahagi). Root development in selected accessions was also evaluated in soil culture. Root development levels in hydroponic and soil culture were significantly correlated. These results will provide important information on waterlogging damage in regions where waterlogging occurs. The three accessions with hypoxia-tolerant roots might be useful for genetic improvement of waterlogging tolerance of modern soybean varieties.     

棉花的防灾减灾

棉花在整个生长期,都可能发生各种气象灾害,导致严重减产。介绍了棉花播种-苗期冷（冻）害、棉花雹灾、棉花雨涝害、棉花旱灾、棉花干热风害、棉花热害、棉花吐絮期霜冻害等灾害的症状,并且针对各种灾害提出了相应的防灾救灾措施。     

S3307对始花期和始粒期淹水绿豆光合作用及产量的影响

淹水胁迫是作物生长发育过程中遭受的主要非生物胁迫之一,探究提高绿豆耐淹性的机制对绿豆抗涝栽培具有重要意义。本文在2017—2018年以耐淹性不同的绿豆品种绿丰2号和绿丰5号为试验材料,采用盆栽方式探究了烯效唑(S3307)对淹水胁迫下绿豆叶片生理、光合作用及产量的影响。结果表明,在不同生育时期淹水胁迫下,绿豆叶片的叶绿素含量(SPAD)及光合特性参数均显著下降,丙二醛(MDA)含量显著增加,始花期(R1期)淹水胁迫下绿豆的减产率为24.70%～33.63%,始粒期(R5期)减产率为18.07%～28.87%。2个绿豆品种均表现为R1期受淹水胁迫危害程度大于R5期,绿丰2号耐淹性强于绿丰5号。喷施S3307后显著提高淹水胁迫下绿豆叶片的SPAD、净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs),并显著降低了MDA含量。绿豆在R1期淹水胁迫下的缓解率为28.91%～52.34%,R5期缓解率为13.77%～27.36%。表明叶面喷施S3307可有效提高淹水胁迫下绿豆叶片的生理功能及光合能力,进而降低减产幅度,但不同淹水时期和绿豆品种对S3307的调控响应存在差异。     

苗期渍水对直播冬油菜产量和农学利用率的影响及油菜在不同氮肥施用下的响应

在轻简化施肥背景下，为减少渍害损失，解决长江流域冬油菜产区生产面临的重要问题，开展氮肥施用 对油菜渍害的缓解作用研究。设置三因素田间试验，分别为不同氮肥用量（0、60、120、180、240和300 kg N/hm2）、氮 肥类型（油菜专用控释尿素和普通尿素）和水分处理（苗期渍水和正常排水），测定各处理产量和氮肥农学利用率， 明确苗期渍水对不同氮素供应水平油菜的影响，并比较油菜专用控释尿素一次性施用和普通尿素分次施用下油菜 对苗期渍水的响应。结果表明，直播冬油菜产量随氮肥施用量增加而提高，至240 kg N/hm2时不再增加。油菜专用 控释尿素一次性施用，在氮肥用量为60～180 kg N/hm2时产量高于普通尿素分次施用；在氮肥用量为240～300 kg N/hm2时，两种氮肥类型产量基本相当。氮肥施用通过增加收获密度、单株角果数和每角粒数提高产量。苗期渍水 导致直播冬油菜产量损失1.1%～41.9%，随氮肥用量增加，渍水引起的产量损失率呈先增加后降低趋势。0～60 kg N/hm2处理时，渍水使收获密度显著降低（降幅达29.4%~45.0%），单株角果数增加；施氮量为120~180 kg N/hm2时， 渍水导致收获密度和单株角果数分别降低19.5%~33.7%和1.4%~17.7%；施氮高于180 kg N/hm2时，收获密度和单 株角果数降幅减小（降幅分别为5%~30.9%和3.6%~9.5%）。普通尿素分次施用和油菜专用控释尿素一次性施用， 分别在施氮量为120和180 kg N/hm2时产量损失率最高，分别达29.8%和41.9%。相同氮肥用量下油菜专用控释尿 素一次性施用的产量损失率大于普通尿素分次施用。渍水显著降低氮肥农学利用率，降幅为8.4%～51.9%，施氮充 足（240～300 kg N/hm2）时氮肥农学利用率降幅低于氮素用量较低处理（120～180 kg N/hm2），油菜专用控释尿素一 次施用处理的农学利用率平均降幅（36.5%）高于普通尿素分次施用（17.3%）。综上可知，苗期渍水时，油菜专用控 释尿素一次施用，会加重油菜受渍影响；土壤氮素供应能力较低时，渍害逆境解除后，适量追施速效氮肥可有效缓 解产量损失，实现油菜稳产。     

淹水对河竹鞭根系统生物量分配及异速生长模式的影响

为了揭示长期淹水对河竹鞭根系统生物量分配及异速生长模式的影响,调查测定了人工喷灌供水(CK)和淹水处理(TR)3、6个月的河竹1年生竹鞭及其根系的生物量,分析了河竹鞭、根生物量分配对淹水环境的适应和响应策略。结果表明: 淹水条件下河竹根系生长受到抑制,生物量分配比例鞭>根。与CK相比,淹水条件下河竹根系生物量及根系生物量/总生物量显著降低,鞭生物量/总生物量升高。随着淹水时间的延长,河竹鞭、根大量生长,生物量显著升高,但根生物量/总生物量、鞭生物量/总生物量和水中鞭生物量/总生物量变化并不明显。河竹鞭、根生物量间的关系在TR和CK处理下均符合幂函数增长关系,但淹水条件下的异速生长指数b要高于CK。研究表明河竹在鞭根系统生长和物质分配上具有较大的生态可塑性和可调节性,可以通过鞭根系统的生物量合理分配和异速生长调节以逐步适应淹水环境。研究结果可为河竹在水湿地和江河湖库消落带植被恢复中的应用提供参考。     

基于耦合PLUS-SCS模型的城市用地内涝风险预测及优化管控——以湖南省长沙市为例

[目的]预测城市未来土地利用情况及内涝风险强度,并探讨未来城市内涝风险的优化管控措施及实施效果,为提升城市内涝防控水平,优化城市用地布局提供参考依据。[方法]以湖南省长沙市为例,借助PLUS和SCS模型,预测基准情景下城市用地布局及其内涝风险情况,将内涝高风险区域作为PLUS模型中的限制转化因子,耦合PLUS和SCS模型,模拟内涝管控情景下城市用地布局及其内涝风险情况。通过对比两种情景下的内涝风险差异来验证优化管控措施实施的效益。[结果]预测基准情景下2035年长沙市建设用地内涝高风险区面积为96.47 km²,在不减少建设用地面积的前提下,内涝管控情景下城市建设用地的内涝风险总面积相比基准情景减少了36.94 km²,其中新增建设用地中的高风险区全部被规避。[结论]未来城市用地内涝风险呈现出显著增加的趋势,耦合PLUS-SCS模型的优化管控方法能够帮助城市规避内涝风险。     

Variation of tolerance to manganese toxicity in Australian hexaploid wheat

High concentrations of manganese (Mn), iron (Fe), and aluminium (Al) induced in waterlogged acid soils are a potential constraint for growing sensitive wheat cultivars in waterlogged‐prone areas of Western Australian wheat‐belt. Tackling induced ion toxicities by a genetic approach requires a good understanding of the existing variability in ion toxicity tolerance of the current wheat germplasm. A bioassay for tolerance to high concentration of Mn in wheat was developed using Norquay (Mn‐tolerant), Columbus (Mn‐intolerant), and Cascades (moderately tolerant) as control genotypes and a range of MnCl₂ concentrations (2, 250, 500, 750, 1000, 2000, and 3000 μM Mn) at pH 4.8 in a nutrient solution. Increasing solution Mn concentration decreased shoot and root dry weight and intensified the development of toxicity symptoms more in the Mn‐intolerant cv. Columbus than in Norquay and Cascades. The genotypic discrimination based on relative shoot (54% to 79%) and root dry weight (17% to 76%), the development of toxicity symptoms (scores 2 to 4) and the shoot Mn concentration (1428 to 2960 mg kg^–1) was most pronounced at 750 μM Mn. Using this concentration to screen 60 Australian and 6 wheat genotypes from other sources, a wide variation in relative root dry weight (11% to 95%), relative shoot dry weight (31% to 91%), toxicity symptoms (1.5 to 4.5), and shoot Mn concentration (901 to 2695 mg kg^–1) were observed. Evidence suggests that Mn tolerance has been introduced into Australian wheat through CIMMYT germplasm having “LERMO‐ROJO” within their parentage, preserved either through a co‐tolerance to Mn deficiency or a process of passive selection for Mn tolerance. Cultivars Westonia and Krichauff expressed a high level of tolerance to both Mn toxicity and deficiency, whereas Trident and Janz (reputed to be tolerant to Mn deficiency) were intolerant to Mn toxicity, suggesting that tolerance to excess and shortage of Mn are different, but not mutually exclusive traits. The co‐tolerance for Mn and Al in ET8 (an Al‐tolerant near‐isogenic line) and the absence of Mn tolerance in BH1146 (an Al‐tolerant genotype from Brazil) limits the effectiveness of these indicator genotypes to environments where only one constraint is induced. Wide variation of Mn tolerance in Australian wheat cultivars will enable breeding genotypes for the genetic solution to the Mn toxicity problem.