同源四倍体水稻与非洲栽培稻杂交的胚胎学观察

以同源四倍体水稻(Oryza sativa,2n=4x=48)和二倍体水稻(Oryza Sativa,2n=2x=24)为母本,以非洲栽培稻(Dryza glarri,2n=2x=24)为父本进行远缘杂交配组,对其杂交结实的胚胎学机理进行了研究。结果表明,非洲栽培稻的花粉粒能在二倍体水稻的柱头上萌发,但萌发频率仅为0．18％～0．56％,花粉管在花柱内的伸长速度比较慢,发生受精的频率比较低,因而二倍体水稻与非洲栽培稻杂交的结实率比较低。然而,非洲栽培稻的花粉粒在同源四倍体水稻的柱头上萌发频率高达12．81％～14．65％,花粉管在花柱内的伸长速度比较快,发生受精的频率比较高,因而同源四倍体水稻与非洲栽培稻杂交的结实率比较高。在同源四倍体水稻与非洲栽培稻的杂交中发现,其受精作用比较特殊,其中包括精细胞与卵细胞的单受精作用,精细胞与次生极核的单受精作用和正常的双受精作用,总受精率和总成胚率分别为7．49％～9．28％和6．61％～8．64％。     

Effects of initial nematode population density and water regime on resistance and tolerance to the rice root-knot nematode Meloidogyne graminicola in African and Asian rice genotypes

The rice root-knot nematode (RKN), Meloidogyne graminicola, is an important pathogen affecting rice production in South and Southeast Asia. Efficacy of resistance and tolerance in selected M. graminicola-resistant African rice genotypes TOG5674, TOG5675 and CG14 and -susceptible Asian rice genotypes IR64 and UPLRi-5 were examined under a range of initial population densities (Pi) and water regimes. Resistance to M. graminicola in resistant rice genotypes was not broken with increasing pathogen pressure (Pi = 15,000 to 60,000 J2/plant). Resistant rice genotypes were even tolerant to the damage and yield loss caused by high pathogen pressure. On the other hand, increasing Pi levels caused more damage on susceptible rice genotypes. Final nematode population densities in the root systems of resistant and susceptible rice genotypes were significantly lower under flooded conditions than under upland and drought conditions. TOG5674, TOG5675 and CG14 were more tolerant to M. graminicola infection even when grown under upland and drought conditions while IR64 and UPLRi-5 were highly sensitive.     

践踏对三种暖季型草坪草生长和生理的影响

以沟叶结缕草、松南结缕草和矮生百慕大3种暖季型草坪草种为试材,分别进行轻度、中度和重度践踏处理,通过观察各种草坪草的生长情况并测定其过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性,比较各草种对践踏胁迫的抗性。结果表明:在践踏胁迫下,各草种的草层高度,叶片宽度均较对照下降;随着践踏强度的增加,沟叶结缕草和松南结缕草的CAT活性和SOD活性没有显著影响,POD活性下降;矮生百慕大在践踏胁迫下,CAT活性和SOD活性有不同程度下降,但POD活性有所提高。在试验设定践踏强度下,沟叶结缕草和松南结缕草耐践踏性指标高于矮生百慕大。     

结缕草成坪综合因素研究 Ⅲ.结缕草草坪运动场的坪床表土层研究

本试验采用菜园土、泥炭和黄砂为基础基质,按不同重量配比模拟运动场草坪生长的坪床表土层,通过理化性状的测试和结缕草草坪质量的考察,对不同坪床表土层作出全面的评价。     

胞外ATP对泡桐花粉萌发和花粉管伸长的效应及其与H2D2的关系

[目的]研究胞外ATP（eATP）对泡桐（Paulownia tomaentosa Steud.）花粉萌发和花粉管伸长的效应及其与过氧化氢（H2O2）的关系。[方法]eATP浓度分别为0、0.2、0.4、0.6 mmol/L,处理时间分别为1、2、3 h;H2O2浓度分别为0、1、2、3、4、5 mmol/L,处理时间分别为1、2、3 h。[结果]eATP和H2O2均显著抑制花粉萌发和花粉管伸长,且表现出明显的浓度和时间依赖效应。过氧化氢清除剂（ASA）和过氧化氢酶（CAT）能够部分阻止eATP对花粉萌发和花粉管伸长的抑制作用,显示eATP抑制花粉萌发和花粉管伸长与其诱导H2O2产生有关。[结论]eATP对花粉萌发和花粉管伸长的效应能够通过诱导H2O2产生而实现。     

Classification of rice genotypes based on their mechanisms of adaptation to iron toxicity

Iron (Fe) toxicity is a nutritional disorder that affects lowland rice (Oryza sativa L.). The occurrence of excessive amounts of reduced Fe(II) in the soil solution, its uptake by the rice roots, and its transpiration‐driven transport result in elevated Fe(II) concentrations in leaf cells that catalyze the formation of reactive oxygen species. The oxidative stress causes rusty brown spots on leaves (bronzing) and the reduction of biomass and yield. While the use of resistant genotypes is the most promising approach to address the problem, the stress appears to differentially affect rice plants as a function of plant age, climatic conditions, stress intensity and duration, and the prevailing adaptation mechanism. We comparatively assessed 21 contrasting 6‐week‐old rice genotypes regarding their response (symptom score, biomass, Fe concentrations and uptake) to a 6 d iron pulse of 1500 mg L^–1 Fe(II). Eight selected genotypes were further compared at different stress intensities (0, 500, 1000, and 1500 mg L^–1 Fe(II)) and at different developmental stages (4‐, 6‐, and 8‐week‐old plants). Based on Fe‐induced biomass reduction and leaf‐bronzing score, the tested spectrum was grouped in resistant and sensitive genotypes. Linking bronzing scores to leaf iron concentrations allowed further differentiation into includer and excluder types. Iron precipitation on roots and organ‐specific iron partitioning permitted to classify the adaptation strategies into root exclusion, stem and leaf sheath retention, and leaf blade tissue tolerance. The effectiveness of these strategies differed with stress intensity and developmental stage. The reported findings improve the understanding of Fe‐stress response and provide a basis for future genotype selection or breeding for enhancing Fe‐toxicity resistance in rice.     

高校毕业生就业区域流向探析——以合肥工业大学为例

本文以合肥工业大学为例, 通过对该校近三届毕业生就业的地域流向进行调查, 分析了理工科高校毕业生地域流向的三个特点及成因, 并就如何做好毕业生就业工作提出有关对策。     

油菜田日本看麦娘对高效氟吡甲禾灵的抗药性检测

为探明江苏省油菜田日本看麦娘(Alopecurus japonicus Steud.)对高效氟吡甲禾灵(haloxyfop-R-methyl)的抗药性以及对芳氧苯氧丙酸(aryloxyphenoxypropionate,AOPP)类和环已烯酮(cyclohexanedione,CHD)类除草剂的交互抗性,本研究从江苏省11个县(市)油菜田采集到12个日本看麦娘种群,以种子生物测定法测定日本看麦娘种群对高效氟吡甲禾灵的抗药性以及对其它药剂的交互抗性。结果表明,采自句容的两个日本看麦娘种群对高效氟吡甲禾灵的相对抗性倍数分别为76.03和61.18,丹阳、高淳和溧阳3个种群的相对抗性倍数分别为5.89、4.37和4.29,最敏感的为宜兴种群,其相对抗性倍数为1.37,证明部分地区日本看麦娘种群对高效氟吡甲禾灵已产生抗药性。交互抗性测定结果表明,抗性种群对AOPP类除草剂已产生不同程度的交互抗性,交互抗性水平依次为精吡氟禾草灵>精喹禾灵>精噁唑禾草灵;而抗性种群对具相同作用靶标的CHD类除草剂烯草酮则较为敏感。     

狼毒大戟水浸液对家蚕的药杀效果

[目的]以家蚕为试验材料,研究药用植物狼毒大戟对鳞翅目昆虫的药杀效果。[方法]取多年生新鲜狼毒大戟根制成水浸液,用于涂抹家蚕背部、浸泡家蚕、涂抹桑叶饲喂家蚕。[结果]用药液涂抹背部的家蚕无明显的中毒症状;浸泡1、3 min的家蚕取出后可存活7 d左右;浸泡5 min的家蚕可存活2 d左右;浸泡15 min的家蚕取出后最多可存活10 h。家蚕取食涂抹狼毒大戟水浸液的桑叶后,2 d内100%死亡。[结论]狼毒大戟水浸液对家蚕具有明显的触杀和胃毒作用。     

油菜田日本看麦娘对高效氟吡甲禾灵抗药性的研究

 【目的】明确油菜田日本看麦娘（Alopecurus japonicus Steud.）对高效氟吡甲禾灵（haloxyfop-R- methyl）的抗药性及对其它药剂的交互抗性水平。【方法】利用种子生物测定法和整株测定法测定了江苏、安徽11个点油菜田日本看麦娘对高效氟吡甲禾灵的抗药性，并用同样方法进行了相关药剂的交互抗性测定。【结果】两种方法测定结果基本相符。种子生物测定结果显示，江苏句容点日本看麦娘对此药剂的相对抗性倍数达61.13，整株测定结果为1 331.68，说明句容点的日本看麦娘对此药剂已产生明显抗性。交互抗性测定结果显示，日本看麦娘对芳氧基苯氧基丙酸酯类（aryloxyphenoxypropionates，简称AOPP）其它药剂已产生了不同程度的抗性，抗性水平依次为精吡氟禾草灵＞精喹禾灵＞精噁唑禾草灵；对具相同作用靶标的环已烯酮类（cyclohexanediones，简称CHD）除草剂烯禾啶的抗性水平相对较低。室内测定结果与田间实际反映情况相吻合。【结论】种子生物测定法可作为杂草抗性水平测定的方法之一。油菜田日本看麦娘对AOPP类高效氟吡甲禾灵已产生不同程度的抗药性，其中句容点抗性最高，对同类产品精吡氟禾草灵的交互抗性水平也最高；对与AOPP类除草剂具有不同结构、相同作用机制的CHD类烯禾啶交互抗性水平较低。