长期施肥条件下水稻土腐殖质组成及稳定性碳同位素特性

利用太湖地区26年水稻土长期定位施肥试验,分析了长期不同施肥处理对土壤剖面有机碳分布和稳定性碳同位素自然丰度(δ¹³C)的影响,以及土壤中不同结合态腐殖质组成的变化.结果表明：长期施肥使水稻土表层土壤有机碳含量显著升高,不同处理土壤剖面有机碳含量与土层深度呈极显著指数负相关(P<0.01);施化肥处理10～30 cm土层和施有机肥处理20～40 cm土层有机碳含量变化相对稳定;随土层深度增加,土壤δ¹³C值逐渐升高,其变化范围在-24‰～-28‰,不同处理土壤剖面有机碳含量与δ¹³C值呈显著线性负相关(P<0.05);0～20 cm土层,仅施有机肥处理(M0)、有机肥+氮+磷处理(MNP)、有机肥+氮+磷+钾处理(MNPK)、有机肥+秸秆+氮处理(MRN)以及秸秆+氮处理(CRN)的δ¹³C值明显降低;30～50 cm土层,除CRN外,有机肥和化肥处理土壤的δ¹³C值均明显升高;不同处理土壤中结合态腐殖质均以紧结合态腐殖质(胡敏素)为主,其含量在50%以上,其余部分为松结合态和稳结合态腐殖质;长期施肥使土壤松结合态腐殖质含量及富啡酸(FA)与胡敏酸(HA)比值(HA/FA)升高.     

用同工酶和RAPD技术研究棉花三元杂种石远321新品种的遗传特性

石远321是从海岛棉×野生色伯氏棉×陆地棉三元杂种后代中选育而成的种间杂交新品种。其细胞学鉴定结果、形态学基本特征以及栽培特性均为陆地棉型。但在丰产性、棉纤维品 质及抗逆性等许多农艺性状和经济性状方面,该品种明显综合了多棉种多亲本的遗传特性。为了从分子水平上认识石远321的三元杂种性质及其变异水平,用等电聚焦电泳和RAPD技术,对石远321及其不同棉种亲本进行了遗传分析。主要结果如下（1）酯酶同工酶图谱分析表明,石远321与其野生棉亲本和海岛棉亲本同具有一条陆地棉亲本所没有的特异带;（2）用4个引物对石远321扩增共发现6个野生棉亲本和海岛棉亲本的特征片段;（3）通过比较石远321与其3个不同棉种亲本之间的RAPD差异,说明石远321在基因组水平上具有高度的遗传异质性。初步从分子水平上证实了石远321为上述3个棉种的种间杂交后代。     

32个柿主栽品种SSR图谱构建及遗传变异分析

以32份柿主栽品种为试验材料,利用SSR标记技术构建其指纹图谱并进行遗传多样性分析。从78对候选引物中筛选出20对多态性高、稳定性好的引物作为核心引物,构建柿主栽品种SSR指纹图谱。结果显示:(1)20对引物在32份材料中共扩增出183条多态性条带,每对引物扩增出3～20条不等,平均每对引物扩增出9.15条,多态性比率为81.3%。各个位点的杂合度在0.410 3～0.914 3之间,平均为0.702 7。(2)8对引物在12个品种上具有特征带型,采用5对引物进行组合鉴定即可将32个柿品种完全区分开。(3)依据SSR带型特征,对每对引物生成的不同带型直接编号,简化柿SSR带型记录方法,并利用每个品种的带型编号,建立其DNA指纹图谱,结果表明,核心引物组合法比特征谱带法更适用于构建中国柿主栽品种DNA指纹图谱。(4)根据系统聚类分析将32个柿主栽品种分为两大类,品种间的亲缘关系与地理来源具有一定的相关性。     

Rice production in a changing climate: a meta-analysis of responses to elevated carbon dioxide and elevated ozone concentration

Rice is arguably the most important food source on the planet and is consumed by over half of the world's population. Considerable increases in yield are required over this century to continue feeding the world's growing population. This meta-analysis synthesizes the research to date on rice responses to two elements of global change, rising atmospheric carbon dioxide concentration ([CO₂]) and rising tropospheric ozone concentration ([O₃]). On an average, elevated [CO₂] (627 ppm) increased rice yields by 23%. Modest increases in grain mass and larger increases in panicle and grain number contributed to this response. The response of rice to elevated [CO₂] varied with fumigation technique. The more closely the fumigation conditions mimicked field conditions, the smaller was the stimulation of yield by elevated [CO₂]. Free air concentration enrichment (FACE) experiments showed only a 12% increase in rice yield. The rise in atmospheric [CO₂] will be accompanied by increases in tropospheric O₃ and temperature. When compared with rice grown in charcoal-filtered air, rice exposed to 62 ppb O₃ showed a 14% decrease in yield. Many determinants of yield, including photosynthesis, biomass, leaf area index, grain number and grain mass, were reduced by elevated [O₃]. While there have been too few studies of the interaction of CO₂ and O₃ for meta-analysis, the interaction of temperature and CO₂ has been studied more widely. Elevated temperature treatments negated any enhancement in rice yield at elevated [CO₂], which suggests that identifying high temperature tolerant germplasm will be key to realizing yield benefits in the future.     

大蒜不同品种蒜薹发育的解剖学研究

通过形态观测和石蜡切片法,比较了2个大蒜品种的蒜薹发育和解剖结构。结果表明：（1）“陇县火蒜”比“改良蒜”蒜薹的表皮细胞形状规则,排列致密;角质层较薄;（2）“陇县火蒜”比“改良蒜”蒜薹表面的气孔数量少,但开张度大;分泌细胞出现早、体积大、数量多;维管束数量少、直径小;（3）“陇县火蒜”蒜薹髓细胞卫多边形,髓细胞间隙率小,而“改良蒜”蒜薹的髓细胞呈椭圆形,髓细胞间隙率大。     

Development and characterization of 20 new polymorphic microsatellite markers from Mangifera indica (Anacardiaceae)

? Premise of the study: Twenty microsatellite loci for mango (Mangifera indica), an important commercial fruit tree in East Asia, were developed to evaluate the genetic diversity and identification of cultivars. ? Methods and Results: The 20 new microsatellite markers were isolated from mango using a magnetic bead enrichment method, and polymorphisms were identified in 22 mango cultivars. The number of alleles ranged from one to nine, with expected heterozygosity ranging from 0 to 0.826. The polymorphism information content ranged from 0 to 0.756 with a mean of 0.525. ? Conclusions: These new microsatellite loci should be useful and convenient for further studies of the genetic diversity and identification of cultivars in mango.     

番木瓜主栽品种SCoT指纹图谱构建及遗传变异分析

利用SCoT标记对中国22个番木瓜主要栽培品种进行遗传多样性分析和指纹图谱构建,为番木瓜品种资源的鉴定和杂交亲本的选配提供技术参考。结果显示:(1)SCoT标记有效等位基因数(Ne)平均为1.47,Nei’s基因多样性指数(H)平均为0.26,Shannon’s信息指数(I)平均为0.39,表明SCoT标记具有较高的多态性检测效率。(2)聚类分析和主坐标分析结果表明,大部分番木瓜品种间的遗传相似系数为0.79~0.90,品种间遗传多样性水平较低;在相似性系数为0.75时可将所有品种分为3个组群。(3)6个SCoT引物可以将22个番木瓜品种完全区分开,每个品种都各有独特的指纹图谱,置信概率达到99.976%。     

番茄吸收和积累Cd能力的品种间差异

旨在筛选和利用在受污染土壤中可食部位污染物积累水平在食品卫生标准允许范围内的农作物品种(pollution-safecultivar,简称为PSC),以降低水土环境污染物经食物链危害人类健康的风险。研究对象为番茄,探讨了在一定Cd污染土壤中其果实Cd含量低于国际食品法典委员会(CAC)Cd最高限值的品种(Cd-PSC)存在的可能性。通过盆栽试验研究了36个番茄品种(包括普通番茄和樱桃番茄两个变种)不同器官在受不同程度镉污染的土壤中吸收和积累Cd能力的差异。结果表明:(1)在土壤Cd重度胁迫(13.3mg.kg-1)和轻度Cd胁迫(1.1mg.kg-1)下,番茄所有器官Cd含量的变异在统计学上均存在极显著意义(p<0.01),其中果实Cd含量的范围分别为0.08~0.33mg.kg-1和0.00~0.09mg.kg-1,变异系数分别达到28.5%和77.9%;(2)在重度胁迫下,所有供试品种的果实Cd含量均超出CAC标准,而轻度胁迫下的Cd含量超标率达到19.4%,说明番茄是易受Cd污染的农作物种类,其中樱桃番茄的受污染风险特别高,在轻度胁迫下6个供试品种中有5个超标,而30个普通番茄品种仅1个超标。因此,仅在轻度胁迫条件下,存在着番茄的Cd-PSC,其中有5个普通番茄品种的果实中未检出Cd,属于比较安全的PSC,包括品种No.121、6、24、35和No.36,可以推荐在土壤Cd污染程度略超国家三级标准或具有潜在受污染风险的区域应用;(3)尽管大多数情况下各营养器官的Cd含量间均呈显著的正相关,但营养器官与果实Cd含量间均无明显的相关性,推测Cd在番茄营养器官间和营养器官与果实间的转运途径是不一样的。组织中Cd含量的显著相关性说明该特性可以作为农作物品种的种性特征;(4)与轻度胁迫相比,重度胁迫下的所有供试品种平均果实生物量上升了7.5%,一半以上的品种表现出较强的耐Cd能力,这一特性可能导致因不易察觉土壤的Cd污染状况而增加番茄产品受Cd污染风险。     

Effect of Water Stress on Photosynthesis in Two Mulberry Genotypes with Different drought Tolerance

Three-month-old mulberry (Morus alba L.) cultivars (drought tolerant S13 and drought sensitive S54) were subjected to water stress for 15 d. Water stress decreased the leaf water potential, net photosynthetic rate (PN), and stomatal conductance (gs) in both the cultivars. However, the magnitude of decline was comparatively greater in the sensitive cultivar (S54). Intercellular CO2 concentration (Ci) was unaltered during mild stress, but significantly increased at severe stress in both cultivars. The photosystem 2 activity significantly declined only at a severe stress in both cultivars. The Ci/gs ratio representing the mesophyll efficiency was greater in the tolerant cultivar S13. Involvement of stomatal and/or non-stomatal components in declining PN depended on the severity and duration of stress. However, the degree of non-stomatal limitations was relatively less in the drought tolerant cultivar.     

不同质量浓度多效唑对碗莲品种'火花'生长和 叶片部分生理指标的影响

研究了不同质量浓度(0~50 mg·L-1)多效唑对碗莲(Nelumbo nucifera Gaertn.)品种'火花'('Huohua')生长的影响及多效唑处理过程中叶片部分生理指标的变化,并进行了隶属函数值分析和相关性分析.结果表明:质量浓度10~50 mg·L-1多效唑处理抑制碗莲品种'火花'生长.随着多效唑质量浓度提高,立叶数、立叶长、立叶宽、立叶高、花径、花高和开花总数总体上呈逐渐降低的趋势,且总体上与对照组(质量浓度0 mg·L-1多效唑)差异显著.随着处理时间延长,质量浓度10~50 mg·L-1多效唑处理组叶片中丙二醛(MDA)含量、过氧化物酶(POD)活性和多酚氧化酶(PPO)活性的变化趋势各异;质量浓度10~50 mg·L-1多效唑处理组叶片中可溶性蛋白质含量和超氧化物歧化酶(SOD)活性,以及质量浓度10、20和30 mg·L-1多效唑处理组叶片中过氧化氢酶(CAT)活性总体上呈先升高后降低的变化趋势,而质量浓度40和50 mg·L-1多效唑处理组叶片中CAT活性则呈逐渐降低的变化趋势.相关性分析结果表明:碗莲品种'火花'生长指标的隶属函数值间以及叶片中可溶性蛋白质含量和POD活性的隶属函数值与生长指标的隶属函数值间的相关性总体在0.05或0.01水平上显著.研究结果显示:质量浓度10、20和30 mg·L-1多效唑处理可有效控制碗莲品种'火花'生长,提高其观赏性;且其生长指标以及叶片中可溶性蛋白质含量和POD活性可以作为判断碗莲品种'火花'矮化效果的可靠、简易指标.