外源褪黑素对NaCl胁迫下5BB葡萄叶片生理特性的影响

以砧木葡萄5BB (Vitis berlandieri×V. riparia 5BB)为材料,用离体叶片培养法进行NaCl胁迫。用3种不同浓度的褪黑素(melatonin,MT)溶液(100、200、500 nmol·L^-1)分别与0.25 mol·L^-1 NaCl溶液混合并将叶片叶柄浸入其中进行培养,研究外源MT对NaCl胁迫下葡萄叶片光合作用和相关生理指标的影响。结果表明,NaCl胁迫下外源MT可有效增强超氧化物歧化酶(SOD)活性,及时清除逆境胁迫下叶片积累的氧自由基,减缓膜质过氧化过程,有效提高逆境胁迫下葡萄叶片中光合色素含量和光合能力。随着外源MT浓度的增加,对葡萄叶片的保护效果逐渐减小。外源MT能提高砧木葡萄5BB对NaCl胁迫的抵抗力,且浓度为100 nmol·L^-1时效果较好。     

不同硅处理方式对干旱胁迫下大麦萌发的影响

【目的】研究不同处理方式下不同浓度的硅对干旱胁迫下大麦萌发的影响,综合评价各处理下大麦幼苗的抗旱性,确定最佳处理。【方法】分别在种子发芽前使用硅溶液浸种(A处理)和在种子发芽的培养过程中向发芽盒里加硅培养液(B处理)两种方式处理新啤6号大麦种子,两种方式均设置0.0、0.5、1.0、1.5和2.0 mmol/L Na₂SiO₃·9H₂O浓度水平,研究对干旱胁迫下大麦发芽指标、形态指标和生长量的影响。【结果】A处理下随着硅浓度的增加发芽势、发芽指数、活力指数、根长、芽长、芽鞘长、根数、根和芽的鲜重与干重均呈现先增加后降低的趋势,而根芽比呈先降低后增加的趋势,发芽率无显著变化。B处理下0.0和0.5 mmol/L Na₂SiO₃·9H₂O浓度下各指标均无显著差异,1.0～2.0浓度区间内根芽比随硅浓度增加呈降低趋势,其他各指标随硅浓度增加而增加。【结论】1.0 mmol/L Na₂SiO₃·9H₂     

富士和嘎啦苹果叶片面积估算模型构建

【目的】建立准确、无损的适宜于苹果不同品种和枝梢类型的叶面积估算模型。【方法】以富士及嘎啦不同长度的营养枝梢和果台枝梢叶片为试材,采用数字扫描仪获取叶片长度(LL)、宽度(LW)和叶面积(LA)等叶片形态参数,并采用决定系数(R²)、均方根误差(RMSE)、赤池信息准则(AIC)对建立的17个有常数项和无常数项叶面积模型精度进行筛选和适宜性评价。【结果】共获得5 207枚叶片形态参数,其中叶面积变异系数最大,达51.59%。叶片形态受品种及枝梢类型的显著影响,其中长枝梢叶片长、宽和叶面积显著大于同类型短枝梢叶片,而营养枝梢叶片长、宽和叶面积显著大于同长度果台枝梢,嘎啦叶片相比富士更为细长。以LL和LW复合变量为自变量的模型5:LA=a(LL×LW)、模型6:LA=a(LL+LW)²、模型9:LA=aLL²+bLW²、模型16:LA=a(LL×LW)^b、模型17:LA=(LL×LW)^b的精度可满足富士和嘎啦各类枝梢叶面积的估算,但需针对各品种和枝梢类型单独建...     

基于拉曼光谱的稻叶瘟病害程度划分研究

随着植保变量喷施作业机械的研究和应用,急需一种高效的病害程度识别技术。为此,针对水稻稻叶病运用拉曼光谱仪采集正常及受病害叶片的光谱特性,通过绘制折线图及受试者工作特征曲线进行水稻受病害程度分析,并运用动量因子BP神经网络优化算法,建立了寒地水稻稻叶瘟的病害程度检测模型。结果表明:优化的BP神经网络算法网络预测集的均方误差为0. 002 409 6、相关系数为0. 998 2。该方法可以较好地区分水稻正常叶片、稻叶瘟重度和轻度叶片,是一种高效的病害程度识别技术。     

Molecular mapping of stripe rust resistance gene YrH9017 in wheat-Psathyrostachys huashanica introgression line H9017-14-16-5-3

Several new stripe rust pathogen races emerged in the wheat growing regions of China in recent years. These races were virulent to most of the designated wheat seedling resistance genes. Thus, it is necessary and worthwhile to identify new valuable resistant materials for the sake of diversifying resistant sources, pyramiding different resistance genes and achieving durable resistance. Here, we identified the resistance gene, temporarily designated as YrH9017, in wheat-Psathyrostachys huashanica introgression line H9017-14-16-5-3. A total of 146 F₂ plants and their derived F_2:3 families in a cross of Mingxian 169 and H9017-14-16-5-3 were used to evaluate seedling stripe rust response and as a mapping population. Finally, we constructed a genetic map including eight simple sequence repeat (SSR) markers and expressed sequence tag (EST) markers. YrH9017 was located on the long arm of chromosome 2A and closely linked with two EST-sequence tagged site (EST-STS) markers BG604577 and BE471201 at 1.3 and 1.8 cM distance, respectively. The two closest markers could be used for marker-assisted selection of YrH9017 in breeding.     

不同水肥作用下西藏青稞生长动力学机制与模拟研究

【目的】构建西藏高原地区多因子作用下的青稞动态生长模型。【方法】于2016─2017年在西藏农牧学院农田水利试验场,监测了不同水分和氮素状态下的青稞动态生长过程,基于方差分析法研究了水分和氮素对青稞动态过程的交互作用,在此基础上构建了包括4个自由度、描述土壤水分和氮素对春青稞干物质形成以及累积过程函数关系,构建了多因子作用条件下的青稞动态关系模型,分别采用2016年和2017年的试验资料对模型进行了参数率定和验证。【结果】西藏高原地区青稞动态生长过程受到了多种因素的影响,青稞的干物质增量和累积量与土壤水分和氮素投入量表现出非线性响应关系;采用偏相关系数能够有效地反映青稞的产量与干物质指标关系。模拟不同水分和氮素条件下的青稞生长过程与实测结果相比,全生育内Nash-Sutcliffe系数平均值为0.873;5%的显著水平下,不存在系统性偏差。【结论】构建的青稞动态生长关系模型能够描述西藏地区气候和土壤条件对青稞生长动态过程影响机理,具有较高的模拟精度。     

高钾用量和根区施肥可提升皖南不同质地土壤烟叶钾含量

钾是烟叶的品质元素之一,提升烟叶钾含量一直是我国烟草行业关注的重点之一。本文选取安徽烤烟主产区皖南宣城市砂土与黏土两类典型土壤,以云烟97为试验材料,研究田间条件下不同高钾用量水平与施肥方式对烟叶钾含量的影响。研究结果表明,在耕层土壤全层混施方式下,随着施钾量增加(0、300、600、900、1 200、1 800、2400mg/kg,以纯K计),两种质地土壤烟叶钾含量均显著上升,呈先快速增加而后缓慢增加的趋势。在钾肥用量低于1 200 mg/kg时,每增加钾肥用量100 mg/kg,砂土和黏土烟叶不同部位钾含量分别平均增加2.4 g/kg和1.0 g/kg。更高钾肥用量可使砂土烟叶钾平均含量提升到44.0 g/kg,黏土则只能提升到26.2 g/kg。两类土壤钾肥效果差异极大的原因与土壤固钾能力有关,土壤速效钾含量与烟叶钾含量呈线性相关,而黏土钾肥固定率平均为71%,远高于砂土的25%,这是两种质地土壤钾肥肥效差异的根本原因。在常规同等钾肥用量条件下(K2O25kg/667m2),氮磷钾根区集中施用较常规条施显著促进了烟叶对钾的吸收,提升了烟叶钾含量,而且砂土的效果要好于黏土,其原因也与根区施肥可显著提升烟叶根区土壤速效钾含量有关。以上结果表明,选择固钾能力弱的土壤,提高钾肥用量并改进施肥方法可以有效提升皖南烟叶钾的含量。     

Responses of aerobically grown iron chlorosis tolerant and susceptible rice (Oryza sativa L.) genotypes to soil iron management in an Inceptisol

Iron deficiency is a serious nutritional disorder in aerobic rice, causing chlorosis, poor yields and reduced grain nutritional quality. The problem can be managed by complementing the use of Fe-efficient plant type with a suitable Fe management strategy. In the present paper, we report the effect of eight iron management practices to resolve the problem of iron (Fe) chlorosis through the use of an iron deficiency tolerant (IDTR) and iron deficiency susceptible (IDSR) rice genotype, i.e. Pusa 33 and ADT 39, respectively. Fe deficiency tolerance of these genotypes was related to the root release of PS which enabled a higher uptake of Fe in the IDTR than the IDSR under Fe deficiency. In general, IDTR performed better than the IDSR as evident from a significant increase in total iron, active iron, chlorophyll content and grain and straw yield. IDSR produced the highest grain and straw yield under slow iron release nano clay complex source. Grain Fe content of the IDTR and IDSR increased by 18.9 and 13.4%, respectively, under recommended dose of Fe. The results identified the most effective soil management strategies for the alleviating Fe deficiency chlorosis and improving Fe nutrition of both IDTR and IDSR genotypes.     

橡胶树叶片不同发育时期SPAD值及叶色动态变化

以橡胶树12个无性系为试验材料,测定叶片从萌动至脱落整个生长周期的SPAD值及记录叶色的动态变化情况,绘制叶片SPAD值随生长时间的变化趋势图,比较分析无性系间叶片SPAD值及叶色动态变化过程的差异与联系,为橡胶树叶片物候期划分提供理论参考。结果表明,橡胶树叶片SPAD值随时间的变化趋势可以分成3个阶段:上升阶段、稳定阶段和下降阶段。叶片颜色在各阶段的表现差异明显,上升阶段包括古铜色、古铜-浅黄色过渡色、浅黄色、淡绿色及绿色,平稳阶段只含深绿色,下降阶段包括深绿-绿带紫过渡色、绿带紫色、黄带红色及黄色。不同物候期无性系间历时时长存在较大差异,且对应的SPAD值差异也较大。186、272、314、277及620等5个无性系萌动至浅色期持续时间较短,而深绿色期持续时间较长,且整个生长期SPAD值相对较高;而551、552及553等3个无性系萌动至浅色期持续时间较长,深绿色期持续时间较短,且整个生长期SPAD值相对较低。建议根据橡胶树叶片SPAD值与叶色相结合将橡胶树叶片生长物候划分成3个阶段11个时期,包括萌动期、古铜期、变色期、浅色期、淡绿期、绿色期;深绿色期;深绿-绿带紫过渡期、绿带紫色期、黄带红色期及脱落期。     

Molecular identification of the powdery mildew fungus infecting rubber trees in China

Powdery mildew is a foliar disease of rubber trees. It is one of the most important leaf diseases in rubber plantations worldwide. The causal agent of this powdery mildew, previously known as Oidium heveae, has been identified under various names. To precisely identify the causal agents of this disease, 57 conidial samples were collected from 2013 to 2017 in Hainan, Yunnan and Guangdong provinces, the main rubber tree planting regions in China. Based on morphological observations using light and scanning electron microscopy, pathogenicity testing, and nrDNA ITS and 28S sequences, Erysiphe quercicola is suggested as the only causal agent of rubber tree powdery mildew in China.