Frost resistance mechanisms in quinoa (Chenopodium quinoa Willd.)

Quinoa (Chenopodium quinoa Willd.) is traditionally grown in the mountain regions of the Andes where frost is common. However, the physiological mechanisms responsible for the frost resistance observed in quinoa are largely unknown. For this reason, a study on cultivars of quinoa originating from the Andean highlands and from the inter-Andean valleys was performed. Frost tolerance was determined by measuring the average lethal temperature of 50% of the leaf tissues (LT₅₀) by ion leakage, and supercooling activity was assessed by thermal analysis using thermocouples. Quinoa demonstrated supercooling capacity (a mechanism that prevents immediate damage by freezing temperatures) of 5 °C. Ice nucleation temperature was always lower than the LT₅₀. This indicates that the main survival mechanism of quinoa to frost is avoidance of ice formation by moderate supercooling. The study revealed that quinoa has a high soluble sugar content, which may cause a lowering of the freezing point and therefore contributing to lower the LT₅₀. It is suggested that the content of proline and soluble sugars, such as sucrose, may serve as indicators of frost tolerance in quinoa breeding material.     

作保灵(TNA)对水稻的保护作用及作用机理研究

研究了作保灵对水稻的保护作用及对氯嘧磺隆的解毒机理。当土壤中氯嘧磺隆残留量为10μg· kg-1时 ,水稻生长发育受到影响,并随着氯嘧磺隆残留量的增加,对水稻的抑制作用明显增强。作保灵 50 mg· kg-1浸种或 200mg· kg-1叶喷都能缓解氯嘧磺隆对水稻产生的药害。作保灵能明显提高水稻体内谷胱甘肽转移酶(GST)活性,增加谷胱甘肽(GSH)、多酚及脯氨酸含量,诱导氯嘧磺隆与谷胱甘肽、多酚进行轭合,从而对氯嘧磺隆进行解毒。     

绿竹P5CS基因的扩增及序列分析

采用同源克隆方法从绿竹基因组中获得2个P5CS基因组片段:Do P5CS1长度为2 178 bp,包含7个内含子和8个外显子,外显子编码序列为976 bp,编码325个氨基酸残基,编码蛋白分子量34.787 4 k D,等电点(PI)5.27,N端有一个氨基酸激酶超家族(Amino Acid Kinases(AAK)superfamily)功能区,C端有一个醛脱氢酶超家族(Aldehyde Dehydrogenase(ALDH)Superfamily)功能区;Do P5CS2大小与Do P5CS1外显子序列相同为976 bp,相似性达99.6%,但缺失内含子,推测Do P5CS2为返座假基因。该研究为基因全长序列的获取和功能分析以及通过分子生物学手段提高绿竹乃至其他竹类植物的抗逆性奠定基础。     

不同品种金银花叶片中脯氨酸对盐胁迫的响应

[目的]研究不同品种金银花（Lonicera japonica Thunb）叶片中脯氨酸对盐胁迫的响应。[方法]采用5个不同浓度（0、100、200、400和600 mmol/L）的NaCl溶液对金银花苗进行盐分胁迫试验,以叶片中脯氨酸含量作为评价指标研究不同品种金银花耐盐碱的特性。[结果]短期盐处理后,树型金银花叶片中脯氨酸含量随NaCl浓度的增加急剧增加;藤状金银花叶片在不同浓度之间无显著差异。但随着胁迫时间的加长,藤状金银花叶片中脯氨酸含量随Nacl浓度的增加而显著增加。2个品种的的金银花脯氨酸含量均为NaCl浓度400 mmol/L处理的值最大。[结论]与藤状金银花比较,树型金银花叶片中脯氨酸对盐胁迫更敏感,表现出较强的渗透调节能力。     

不同维生素浸种对玉米种子萌发的影响

以玉米杂交种郑单958为试验材料,采用不同质量浓度50、100、200 mg/L的水溶性维生素V_(B1)、V_(B2)、V_(B6)、V_(B12)、V_C、V_H、V_(PP)浸种24 h,处理后分析玉米种子萌发及胚芽和根生长中脯氨酸等可溶性调节物质情况。结果表明,供试维生素在100、200 mg/L处理下基本都呈现对种子萌发指数的促进,其中,100 mg/L维生素处理对种子萌发率促进效果显著;200 mg/L维生素处理对种子发芽势显著促进作用;50 mg/L维生素对上述3个指标的影响不同。与未处理对照相比,不同种类维生素和不同质量浓度的同一维生素对根冠比影响不同。维生素浸种均可引起玉米胚芽可溶性糖含量显著升高,外源维生素浸种处理可显著影响玉米种子萌发和胚芽及胚根的生长,且不同维生素在不同浓度下对各生长指标影响及脯氨酸等可溶性调节物质变化不尽相同,对种子萌发呈显著促进作用的V_(B2)和V_(B12)在玉米种子萌发中应用前景较好。     

新型香稻渝恢2103香味分子遗传特性分析

香味是优良稻米品质的重要衡量标准之一,2-乙酰-1-吡咯啉(2AP)是最主要的香味物质,然而2AP生物合成机理至今仍未确凿。本研究筛选了与2AP生物合成密切相关的甜菜碱脱氢酶2基因(Badh2)在30份水稻材料中的3种突变类型,从中发现1份新的香稻材料渝恢2103,该材料Badh2基因序列编码区无突变,遗传分析显示渝恢2103与badh2-E7突变型香稻宜香1B香味基因不等位,与非香稻杂交F2香与非香分离比接近9∶7,与香稻杂交F2香与非香分离比接近7∶9,表明渝恢2103的香味受多基因控制。进一步利用实时荧光定量PCR技术(qRT-PCR)比较了与2AP生物合成相关基因在日本晴、渝恢2103和宜香1B的表达情况,结果显示,Badh2基因在日本晴和渝恢2103中表达差异不大,但在宜香1B中表达量异常高;多数脯氨酸与谷氨酸代谢途径相关基因在宜香1B中的表达水平显著高于日本晴和渝恢2103;推测宜香1B的2AP合成同时受Badh2基因以及脯氨酸与谷氨酸代谢途径相关基因的影响;渝恢2103香味形成可能与这些基因无必然联系。渝恢2103特殊的遗传特性可能为水稻香味形成机理研究提供新的突破点。     

聚乙二醇模拟水分胁迫对桑树种子萌发和生理的影响

以丰驰桑种子为材料,研究了不同浓度(0、1.0、2.5、5.0、7.5、10.0 g/L)的聚乙二醇-6 000(PEG-6 000)模拟干旱处理对桑树种子发芽和生理的影响。结果表明:用1%PEG处理后,种子的平均发芽速度、发芽率和发芽势较对照高;其他处理随胁迫强度的增加呈现明显下降趋势(均低于对照)。10%PEG处理的种子在试验开始第5天后仍未萌发。随胁迫加重脯氨酸含量先降低后升高;而可溶性蛋白和可溶性糖含量随胁迫加重呈上升趋势。     

茄子嫁接抗黄萎病与叶片叶绿素含量、相对电导率和游离脯氨酸含量的关系

以野生茄子托鲁巴姆为砧木,以快圆茄为接穗,研究了茄子嫁接抗黄萎病与叶片叶绿素含量、相对电导率和游离脯氨酸含量的关系。结果表明:1)植株叶片中叶绿素含量为砧木>嫁接株>对照,差异达极显著水平,与发病率呈负相关趋势。2)植株叶片相对电导率和游离脯氨酸含量均为砧木<嫁接株<对照,差异达极显著水平,与发病率呈正相关趋势。     

高温条件下瓠瓜品种比较试验

研究了8个夏季保护地栽培瓠瓜品种脯氨酸含量的变化。试验结果表明,相同的高温栽培条件下,各品种脯氨酸含量差异明显。5号品种(组合)高温条件下叶片脯氨酸含量中等,产量高,商品瓜短、粗,肉质较糯,符合目前由传统长瓠转向较短类型和品质好的瓠瓜消费需求,可作为夏季高温设施栽培品种。     

Mycorrhizal fungi and earthworms reduce antioxidant enzyme activities in maize and sunflower plants grown in Cd-polluted soils

Changes in plant antioxidant enzymes (AOEs) in response to cadmium (Cd) pollution are an important mechanism for plant growth and tolerance to Cd-induced stress. The main objective of this greenhouse study was to determine the combined influence of earthworm and arbuscular mycorrhiza (AM) fungal inoculation and their interactions with Cd on AOEs and proline accumulation in leaves of two major crops under Cd stress. Maize (Zea mays L.) and sunflower (Helianthus annuus L.) plants were exposed to Cd stress (10 and 20 mg kg⁻¹ soil), inoculated with either earthworm (Lumbricus rubellus L.) or AM fungi (Glomus intraradices and Glomus mosseae species) in a pot experiment for three months. Exposure to Cd decreased shoot dry weights, increased shoot Cd and P concentrations, leaf proline accumulation and the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) in both mycorrhizal and non-mycorrhizal plants and both in the presence and absence of earthworms. Inoculation of both model plants with earthworms and AM fungi decreased shoot Cd concentrations and the activity of all AOEs, except PPO. Although earthworm activity enhanced the proline content of sunflower in Cd-polluted soils, the proline level of both plants remained unaffected by AM fungi. AM fungi and earthworms may decrease the activity of AOEs through a decline in shoot Cd toxicity and concentration, confirming that plant inoculation with these soil organisms improves maize and sunflower tolerance and protection against Cd toxicity. Generally, the effect of AM fungal inoculation on plant responses to Cd addition was greater than that of earthworm activity. Nonetheless, the interactive effect of AM fungus and earthworm is of minor importance for most of the plant AOEs in Cd-polluted soils.