耕作方式对不同抛秧水稻品种立苗期根系生长的影响

对不同耕作方式2种基因型水稻的立苗期根系特性进行研究.结果表明:两优培九、金优253立苗期免耕抛秧单株根干重、单条根长、根毛区长略低于常耕抛秧,但差异不显著.免耕提高了水稻立苗后期总根数、白根数、根系活力和超氧化物歧化酶活性.立苗期超级稻两优培九的单株根生物量、总根数、一次分枝、二次分枝根数量、根系活力和超氧化物歧化酶活性均显著高于金优253.     

Selection of Rice Genotypes for Salinity Tolerance Through Morpho-Biochemical Assessment

The present study reported the morpho-biochemical evaluation of 15 selected rice genotypes for salt tolerance at the seedling stage. Growth parameters including shoot length, root length, plant biomass, plant turgid weight, plant dry weight along with relative water content were measured after exposure to saline solution （with electrical conductivity value of 12 dS/m）. Genotypes, showing significant differential responses towards salinity in the fields, were assessed through 14 salinity-linked morpho-biochemical attributes, measured at 14 d after exposure of seedling in saline nutrient solution. Relative water content, chlorophyll a/b, peroxidase activity and plant biomass were identified as potential indicators of salt tolerance. Principal component analysis and successive Hierarchical clustering using Euclidean distance revealed that Talmugur, Gheus, Ghunsi, Langalmura, Sabitapalui, and Sholerpona were promising genotypes for further breeding programmes in rice. The maximum Euclidean distance was plotted between Thavallakanan and Talmugur （7.49）, followed by Thavallakanan and Langalmura （6.82）, indicating these combinations may be exploited as parental lines in hybridization programmes to develop salinity tolerant variety.     

不同耐铝大麦品种对铝锰互作胁迫的生理响应研究

铝（Al）和锰（Mn）是限制酸性土壤作物生长的两大主要因素。以耐铝性差异较大的两个大麦品种为材料,研究了不同处理对大麦生长、叶片功能和氧化胁迫指标的影响。结果表明,与对照相比,铝毒害导致大麦根长下降,根系干物质量降低,锰毒害显著降低植株株高和地上部干物质量,铝锰共存时锰加重大麦铝毒害。铝锰胁迫降低功能叶叶绿素含量和光合能力,复合处理下叶片功能指标下降幅度高于单独铝或锰处理。胁迫处理下叶片功能指标的下降幅度以叶绿素a含量和叶片蒸腾速率最明显。胁迫处理对铝敏感品种的生长和叶片功能毒害强于耐铝品种。铝锰胁迫引起大麦功能叶丙二醛（MDA）含量增加,过氧化物酶（POD）和 超氧化物歧化酶（SOD）活性增强,铝敏感品种增幅更大,复合处理时两品种叶片 MDA 积累量及铝敏感品种 POD 和 SOD 活性增幅显著高于单独铝或锰处理。     

不同耐铝性大麦品种对铝锰胁迫的生理响应

为进一步明确大麦品种对铝锰胁迫的生理效应,研究了不同胁迫处理对大麦生长、叶片功能和氧化胁迫指标的影响。结果表明,铝毒害导致大麦根长和根系干物质量降低,锰毒害显著降低植株株高和地上部干物质量,铝锰共存时锰加重了大麦铝毒害。铝锰胁迫降低了功能叶叶绿素含量和光合能力,铝锰复合处理下叶片功能指标下降幅度高于单独铝或锰处理。胁迫处理下叶片功能指标的下降幅度以叶绿素a含量和叶片蒸腾速率最明显。胁迫处理对铝敏感品种的生长和叶片功能毒害强于耐铝品种。铝锰胁迫引起大麦功能叶丙二醛（MDA）含量增加,过氧化物酶（POD）和超氧化物歧化酶（SOD）活性增强,铝敏感品种增幅更大,复合处理时两品种叶片MDA积累量及铝敏感品种POD和SOD活性增幅显著高于单独铝或锰处理。     

磷、铝胁迫对玉米幼苗生长和养分吸收的影响

选取5个基因型玉米品种,采用营养液培养,研究低磷和铝毒条件下不同基因型玉米苗期生长状况及对磷、钾、钙、镁、铁、锌的吸收。结果表明,耐低磷基因型玉米品种适应低磷的能力较强,具有较长的根系和较大的根干重,株高受低磷的影响明显小于敏感基因型玉米品种。低磷胁迫增大了植株的根冠比,改变了植株对营养元素的吸收及其地上部和根系的分配。铝胁迫下,铝敏感基因型玉米品种根伸长受到铝的抑制作用大于耐铝基因型玉米品种,各种营养元素的吸收累积明显受抑制,耐铝基因型玉米品种地上部和根系相对干重下降较少,而敏感基因型玉米品种相对干重显著下降。     

小麦苗期抗旱相关形态指标的灰色关联度分析

为了系统研究小麦苗期形态指标与抗旱性的关系并筛选有效的抗旱性指标,使用PEG-6000模拟干旱胁迫,采用灰色关联度分析法分析了28份小麦品种苗期干旱胁迫下的苗高、最长根长、根数、地上部鲜重、地上部干重、根鲜重、根干重、叶片数、根冠比等9个形态指标与抗旱系数的关联程度,并以所得加权抗旱系数对各品种进行聚类分析.结果显示,各形态指标与抗旱系数的关联度依次为:叶片数(0.817)>苗高(0.766)>地上部干重(0.746)>地上部鲜重(0.729)>根数(0.699)>根干重(0.688)>根鲜重(0.681)>根冠比(0.645)>最长根长(0.399).研究还表明,9个形态指标可分为叶片相关因子、地上部生物量因子和根部生物量因子三大类,地上部生物量因子的关联度大于根部生物量因子;不能只通过差异显著度检验来判断某一指标是否可以用作抗旱性鉴定;聚类结果能较好地反映各小麦品种的地域分布.因此,进行小麦品种苗期抗旱性鉴定时,应加强对地上部形态指标的选择和鉴定,以提高选择效率.     

油菜毯状育苗的基质改良Ⅱ合理配施磷酸氢二铵

在常规蔬菜育苗基质中合理的配施磷酸氢二铵可以为油菜毯状苗的生长提供所需的磷和氮。通过在常规蔬菜基质中施用不同量的磷酸氢二铵,测量油菜毯状苗生长过程中的生物量、存苗数、叶面积、绿叶数、总叶数、株高、根颈长和根颈直径等指标发现:施用磷酸氢二铵可以显著增加油菜的存苗数、生物量、叶面积、绿叶率和根颈直径,降低生长期间的死苗率。对施用量与地上部干重、地下部干重和单株叶面积的回归分析结果显示,在使用标准水稻育秧盘培育油菜毯状苗时,最适磷酸氢二铵施用量为每盘6 g左右。     

育苗伴侣用量对机插秧秧苗生长的影响

为探明"育苗伴侣"在成都平原稻麦两熟模式下机插秧育秧中的适宜用法与用量,以杂交稻组合德优4727为材料,对不同用量"育苗伴侣"在机插秧育秧中的效果进行了试验。结果表明,在水育旱管育秧模式下,采用30 g/盘的用量,采取与营养土混匀装盘方式,40 d秧龄时,秧苗生长整齐,成苗率高,对叶龄的影响较小,极显著提高秧苗鲜质量、秧苗干质量、充实度、根数、根鲜质量、根干质量,从而使秧苗生长矮健,满足插秧机的作业要求。     

大豆对酸铝土壤的适应性研究Ⅰ大豆耐酸铝毒性材料的鉴定研究

本研究进行了田间、温室土壤盆栽及营养液栽培筛选鉴定试验,以评价大豆基因型的耐酸铝性差异及其几种筛选方法的一致性。结果表明,不同大豆基因型间存在明显的耐酸性差别;几种筛选方法的一致性较好。在田间试验中,秋种大豆受害比春种严重,而且秋种与其他筛选方法较一致,因此应以秋种筛选为主。铝毒主要危害大豆的根部,因此盆栽和营养液试验主要应以根部的耐性差异进行评价,而株高受酸铝毒的影响较小,在５ｍ ｇ／ Ｌ和８ｍ ｇ／ Ｌ处理下多数品种株高高于０ｍ ｇ／ Ｌ处理,但在幼苗期虽然大豆根部受害,但受害程度与收获时差别较大,４０ 天收获的结果与其他筛选方法较一致。在铝毒和干旱的双重胁迫下,没施石灰的处理明显表现出干旱症状,但耐铝毒强的品种表现耐旱性强。本试验中来自南方酸性红壤地区的品种耐性明显较好,而东北品种耐性较差,这说明筛选大豆耐铝毒种质应以原产我国南方的大豆品种为主。     

Morpho-Physiological Changes in Roots of Rice Seedling upon Submergence

Submergence is a serious environmental condition that causes large loss in rice production in rain fed lowland and flood affected area. This study evaluated morphological and physiological responses of rice roots to submergence using two tolerant rice genotypes FR13A and Swarna-Sub 1 and two sensitive ones Swarna and IR42. The tolerant genotypes had higher survival rate and less shoot elongation but greater root elongation during submergence than the sensitive ones. After submergence,the tolerant genotypes also had higher root dry weight and more active roots than the sensitive ones.Tolerant genotypes exhibited less root injury, with less malondialdehyde production and slower electrolyte leakage after submergence. Tolerant genotypes also maintained higher concentrations of soluble sugar and starch in roots and shoots and higher chlorophyll retention after submergence than the sensitive ones.Our data showed that root traits such as root activity and root growth are associated with survival rate after submergence. This is probably accomplished through higher energy supply, and membrane integrity is necessary to preserve root function and reduce injury during submergence. These root traits are important for submergence tolerance in rice.     

氮高效水稻品种苗期耐低磷种质的筛选与鉴定

以先前通过田间试验筛选出来的36个氮高效水稻品种为供试材料,在苗期进行了耐低磷筛选,并对获得的3个耐低磷和2个低磷敏感品种响应磷素胁迫的生理机制进行了初步研究。结果表明:1)正常供磷和低磷条件下,所有调查性状的相对值(低磷/正常供磷)中,相对根系干质量、相对地上部干质量、相对根冠比和相对分蘖数均具有较大的品种间变异(变异系数分别为16.9%、10.9%、11.4%、16.3%)。相关分析表明,它们呈显著或极显著正相关。因此,这4个性状可以作为水稻苗期耐低磷筛选的评价指标。2)在低磷条件下,筛选出的3个耐低磷品种比2个低磷敏感品种的根系生长旺盛且活力强,P吸收动力学参数中Km、Cmin小,而Vmax大,酸性磷酸酶(APase)活性升幅大,磷效率在两者之间也存在显著差异。同时,不同耐低磷品种适应低磷胁迫的调节机制也有所不同。表明筛选氮磷双高效的水稻品种是可行的,同时也为后续基因定位和遗传机制的研究提供了材料和生理学依据。     

玉米自交系苗期耐热性综合评价

以21份骨干玉米自交系为研究材料,播种后21 d进行5 d的高温处理,测定株高、茎粗、叶面积、地上鲜重、地上部干重、总干重、胚根长、地下部分干重、根冠比和SPAD值共10个性状的耐热系数,运用主成分分析、隶属函数法、聚类分析及灰色关联度相结合的方法,对玉米自交系的耐热性进行综合评价。结果表明,主成分分析将10个单项指标转换为3个相互独立的综合指标,代表了全部数据83.16%的信息量。通过隶属函数法技术综合耐热评价值(D),进行聚类分析,将21份自交系按耐热性强弱划分高耐热型、中耐热型、弱耐热型和热敏感型4类,筛选出2份高耐热型自交系KW4M029和DM08。总干重可以作为玉米自交系苗期简单、直观的耐热性鉴定指标。     

大麦单倍体细胞水平与植株水平耐低氮性的关系

为了确定大麦籽粒产量和苗期耐低氮能力与小孢子培养阶段的氮胁迫下愈伤组织产量之间是否存在一致性,以2份大麦基因型为供试材料,进行了以下3项研究：（1）培养基中水解干酪素和谷氨酰胺使用量对小孢子培养愈伤组织产量的影响;（2）营养液中NH₄NO₃不同添加量对大麦苗期生长量的影响;（3）盆栽时正常施氮与不施氮处理对大麦单株产量的影响。结果表明,培养基中氮含量的下降明显降低小孢子培养愈伤组织产量,2份基因型的降幅存在明显的差异;营养液中氮使用量的下降明显降低植株高度、主根长度和植株及根干重,2份基因型之间的降幅也存在明显的差异;盆栽时不施氮处理的大麦有效穗和单株产量低于正常施氮的对照,2份基因型间有差异。氮素胁迫下,2份基因型小孢子培养愈伤组织产量的相对值与苗期植株高度、茎叶干重、主根长度和根干重的相对值以及单株产量的相对值存在一致性,说明供试基因型小孢子水平与植株水平的耐低氮性存在相关性。     

不同育秧方式对水稻秧苗素质及产量性状的影响

以岗优188和南粳9108为材料,研究了泥质法露天育秧、营养土露天育秧和营养土工厂育秧3种育秧方式对秧苗素质及产量性状的影响。结果表明,不同育秧方式对供试品种的大田生育期并无明显影响;泥质法露天育秧所育秧苗茎基宽最高,但秧苗叶面积最小,营养土工厂育秧所育秧苗的地上部鲜质量和干质量明显高于泥质法露天育秧;泥质法露天育秧所育秧苗根数最多,但根鲜质量和根干质量以营养土露天育秧最高;产量方面,2个供试品种均以泥质法露天育秧最高,其次是营养土露天育秧,营养土工厂育秧最低,泥质法露天育秧产量较高的原因在于其每穗总粒数和结实率较高。     

花生幼苗期耐盐品种的筛选与评价

研究以花生幼苗的相对主根长、相对苗高、相对地上部鲜重、相对根鲜重、相对地上部干重、相对根干重等为指标,鉴定了49份花生品种的耐盐性。结果表明,不同浓度NaCl胁迫对幼苗各个性状都有不同程度的抑制效应,其中,除干重以外,0.5%NaCl及以上浓度胁迫条件下所有性状受到盐害的明显抑制。以0.5%NaCl处理条件下的相对主根长、相对苗高等6个性状作为耐盐评价指标,筛选出4份耐盐品种和2份盐害敏感品种,为进一步开展耐盐花生品种的培育以及耐盐机制研究奠定了良好的基础。     

育秧方式对免耕稻立苗期根系生长特性的影响

研究了编织布隔层旱育秧、编织布隔层湿润育秧和塑盘旱育秧3种育秧方式对免耕稻立苗期的根系生长的影响。结果表明,立苗期编织布隔层旱育秧和编织布隔层湿润育秧处理的单株总根数、白根数、一次分枝根数量、二次分枝根数量、根半径、根表面积、根冠比、单株根生物量、根系活力和超氧化物歧化酶活性均显著或极显著高于塑盘旱育秧处理。编织布隔层育秧对免耕水稻单条根长影响不大,但促进了根毛的生长。与编织布隔层湿润育秧处理相比,编织布隔层旱育秧对根系生长的促进作用更大。     

Characterization and Selection of Phosphorus Deficiency Tolerant Rice Genotypes in Sri Lanka

Phosphorus（P） deficiency in soil is a major constrain for rice production. An important set of rice genotypes（landraces, old improved and new improved varieties） were screened for P deficiency tolerance in two major cropping seasons of Sri Lanka, in 2012. The Ultisol soil, which was collected from a plot cultivated with rice without fertilizer application for past 40 years（P₀） at the Rice Research and Development Institute（RRDI）, Bathalagoda, Sri Lanka, was used as the potting medium for greenhouse trials. Two field trials were conducted in the same plots at RRDI. Both P₀ and P₃₀（30 mg/kg P₂O₅） conditions were used in the two greenhouse trials. At the early vegetative（three weeks after transplanting）, late vegetative（six weeks after transplanting） and flowering stages, plant height and number of tillers per plant were recorded. At the flowering stage, shoots were harvested and shoot dry weight, shoot P concentration, shoot P uptake and P utilization efficiency were measured. All data were statistically analyzed using analysis of variance, regression and cluster procedures. The measured parameters were significantly different between P₀ and P₃₀ conditions（P < 0.05）. Higher shoot dry weight was reported by the rice genotypes H4 and Marss under P₀ conditions. The regression analysis between shoot dry weight and P utilization efficiency revealed that the studied rice genotypes could be categorized to three P deficiency tolerance classes. A total of 13 genotypes could be considered as highly tolerant and 4 genotypes as sensitive for P deficiency. These results could be used to select parental genotypes for breeding and genetic studies and also to select interesting varieties or landraces for organic rice production.     

Identification of QTLs for Cadmium Tolerance During Seedling Stage and Validation of qCDSL1 in Rice

Cadmium(Cd)is a non-essential toxic metal that is harmful to plants.To investigate the genetic mechanism of Cd tolerance in rice,quantitative trait loci(QTLs)associated with Cd tolerance at the seedling stage were analyzed using a recombinant inbred line(RIL)population derived from a cross between PA64s and 93-11.A total of 36 QTLs associated with shoot length,root length,shoot dry weight,root dry weight and total dry weight were detected in Hangzhou and Lingshui of China.Among them,15 QTLs were identified under the control condition and 15 QTLs were identified under the Cd stress condition,and 6 QTLs for Cd tolerant coefficient were detected on chromosomes 1,3,7 and 9.The qCDSL1.1 and qCDSL1.2 were identified in Hangzhou and Lingshui,respectively,and had overlapping intervals on chromosome 1.To further confirm the effects of qCDSL1.1 and qCDSL1.2,we developed a chromosome segment substitution line(CSSL),CSSLqCDSL1,in 93-11 background harboring qCDSL1.1/qCDSL1.2 from PA64s.Compared to 93-11,CSSLqCDSL1 had increased shoot length under the Cd stress condition.These results pave the way for further isolation of those genes controlling Cd tolerance in rice and marker-assistant selection of rice elite varieties with Cd tolerance.     

苗期大豆根系及地上部性状与耐旱性的关系

选用耐旱性较强的野生大豆SNWS0048和综合性状优良但不耐旱的育成品种晋大73为亲本,构建回交自交系(BIL)群体。连续2 a在人工控制环境下,检测不同水分条件下该大豆群体的苗期根系及地上部性状,采用相关及通径分析研究了大豆根系及地上部性状与耐旱性的关系,同时探讨了这些性状的遗传特性。结果表明:在干旱胁迫下株高、茎重、根长和根重均有所下降,根冠比有所升高。干旱胁迫下的耐旱系数与所有性状呈正相关,其中与主根长、根重、根冠比极显著相关,与茎重显著相关,与株高相关不显著。通径分析进一步表明正常供水条件下根干重对大豆耐旱性有重要影响,而干旱胁迫条件下根冠比对大豆耐旱性的影响较大。     

水分管理对免耕抛秧水稻根系生长及产量的影响

研究了水分管理对免耕水稻根系生长和产量的影响。结果表明,干湿交替灌溉对根系的伸长、生长、生理及分布具有较大影响,水稻各生育期干湿交替灌溉处理水稻单株根干质量、单株生物量、根半径、根表面积、总根数、根系活力、超氧化物歧化酶活性均显著高于淹水淹灌。干湿交替灌溉处理实收产量显著高于淹水淹灌,增产主要因子是有效穗数、每穗粒数和结实率。灌浆盛期干湿交替灌溉处理单株生物量、根半径、根表面积、总根数、超氧化物歧化酶活性均显著高于湿润淹灌,水稻产量差异则不显著。