Influence of soil type and genotype on Cd bioavailability and uptake by rice and implications for food safety

Cadmium (Cd) entering the human body via the food chain is of increasing concern. This study investigates the effects of soil type and genotype on variations in the Cd concentrations of different organs of nine rice plants grown on two types of soils with two Cd levels. Cd concentrations in nine rice cultivars varied significantly with genotype and soil type (P < 0.01). The Cd concentration was higher in red paddy soil (RP) than in yellow clayey paddy soil (YP). The average Cd concentrations of different organs in three rice types were indica > hybrid > japonica for the Cd treatments and controls. The polished grain concentration in YP and RP soils had a range of 0.055-0.23 mg/kg and 0.13-0.36 mg/kg in the Cd treatment, respectively. Two rice cultivars in YP soil and five rice cultivars in RP soil exceeded the concentration limits in the Chinese Food Hygiene Standard (0.2 mg/kg). The Cd concentrations in roots, stems, and leaves were all significantly and positively correlated to that in polished grain in a single test. The Cd concentrations in polished grain were positively and significantly (P < 0.01) correlated with the calculated transfer factors of stem to grain and leaf to grain Cd transfer. The results indicated that the variations of Cd concentration in grain were related to Cd uptake and the remobilization of Cd from stem and leaf to grain. Also, the cultivars with a strong tendency for Cd-accumulation should be avoided in paddy soil with low soil pH and low organic matter content to reduce the risks to human health from high Cd levels in rice.     

不同基因型杨树的光合特征与臭氧剂量的响应关系

采用开顶式气室装置研究不同臭氧浓度对3种基因型杨树(‘546’、‘90’和‘84K’)光合作用特征的影响.结果表明,随着O_3浓度的升高,净光合速率(P_n)、蒸腾速率(T_r)、水分利用效率(WUE)、电子传递速率(ETR)、PSⅡ反应中心激发能捕获效率(F'_v/F'_m)、光化学猝灭系数(q P)、PSⅡ实际光化学量子效率(Phi PS2)、叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素总量(Chla+b)和类胡萝卜素(Car)均显著降低,胞间CO_2浓度(c_i)显著升高,气孔导度(G_s)变化不显著.不同基因型杨树各项光合生理指标之间均存在显著性差异,基因型‘546’各项光合指标(除G_s外)与O_3剂量(AOT40,小时O_3浓度大于40nmol·mol~(-1)的累计值)间具有显著的线性相关关系(P0.01),并且光合色素含量随着O_3浓度的升高而显著降低.但高浓度O_3对基因型‘90’和‘84K’光合色素影响不显著.从多数光合特征指标特别是叶绿素总量的O_3剂量线性响应关系来看,基因型‘546’表现出最大的斜率,基因型‘90’次之,基因型‘84K’斜率最小,因而可得知随着O_3浓度升高,三者的臭氧敏感性为‘546’‘90’‘84K’.该研究结果为O_3污染环境下杨树基因型筛选与培育,以及保护杨树免受O_3伤害提供科学依据.     

不同基因型水稻吸镉差异及其与根表铁氧化物胶膜的关系

采用琼脂培养方法，模拟铁在不同基因型水稻根表的氧化与淀积，研究了不央水稻吸镉的差异及其有表铁氧化物胶膜的关系，结果表明不同水稻基因型其根表淀积换的氧化物数量存在显著性差异，根表富集的镉量及根部，地上部合镉量均存在显著性差差，且镉在不同水稻植株体内转移运输能力不同；不同水稻基因型根膜中的含铁量与根表铁氧化物富集的镉量、根部的含镉量、地上部的含量存在显著性年线相关。     

钝化与叶面阻控对不同基因型红菜苔镉累积的影响

为探索中轻度重金属镉(Cd)污染农田安全利用技术,实现农产品安全生产,以两种不同镉累积基因型红菜苔为供试作物,采用盆栽试验的方法,分别于两种作物上设置相同的6个处理:对照(CK)、添加3%(质量分数)生物质炭(BC)、添加0.17%钙镁磷肥(CMP)、叶面喷施3 mg·L~(-1) Na_2SeO_3的水溶液(Se)、 BC+Se和CMP+Se,研究不同处理土壤镉有效性变化及植株不同部位镉累积特征.结果表明:①相同处理下,低镉累积基因型金秋红三号红菜苔根部土壤有效态镉含量均显著低于高镉累积基因型十月红.BC和CMP两种钝化剂对金秋红三号根部土壤中的镉钝化效果显著,且BC效果更佳,钝化处理的效果显著优于叶面阻控.②金秋红三号红菜苔根系较十月红对镉有更强的富集能力,其富集的镉倾向于囤积在根部.叶面施硒与两种钝化剂对抑制镉向红菜苔可食部位转移富集无协同效果.③在BC和CMP钝化处理下,金秋红三号红菜苔可食部位镉含量低于GB 2762-2017中镉限量值(0.10mg·kg~(-1)).本研究表明,针对中轻度镉污染农田土壤,通过施加生物质炭、钙镁磷肥等绿色钝化剂,种植弱吸收低积累作物品种,可以实现受镉污染农田的安全利用和农产品的安全生产.     

收获后不同小麦品种土壤硝态氮残留量的差异研究

研究不同小麦品种收获后土壤中硝态氮残留量的差异，及其影响因素，对１２个冬小麦品种的研究证明，在低氮和高氮两个施氮处理中，硝态氮残留量均表现明显的品种间差异。     

酸胁迫对不同基因型玉米生长和钙镁养分吸收的影响

采用盆栽试验系统研究了不同耐酸特性的4个玉米自交系苗期、拔节期和散粉期的生长状况和钙、镁营养特性.结果表明,铝毒对玉米生长发育的影响贯穿于全生育期,但是影响强度随时间推移而减轻.在苗期,铝毒严重影响玉米对钙、镁营养的吸收,且对钙吸收的影响大于镁,不同基因型间存在明显差异.与酸敏感自交系相比,耐酸自交系苗期可保持较高的钙、镁浓度,地上部钙、镁耐酸指数显著高于酸敏感自交系.苗期之后,玉米钙、镁营养受酸胁迫的影响相对较小,除散粉期耐酸自交系功能叶中钙镁比表现较稳定外,其它钙镁营养特性没有表现出明显规律.     

No difference in activity of Sod-1 genotypes of Poa annua to short-term treatment of ambient gaseous organic pollution

Our previous studies indicated that genotypes at locus Sod-1 of Poa annua changed clinally along a gradient of gaseous organic pollution. In the present study, we aimed to know whether there were differential responses of activities of different superoxide dismutase （SOD） genotypes to short-term treatment of ambient gaseous organic pollution. Significant bias from Hardy-Weinberg equibrium was observed on locus Sod-1, and no genotype Sod- l-BB was found. Significantly increased activities were observed in most treatments for genotype Sod-1-AA and in one treatment for genotype Sod-1-AB. However, no significant difference in SOD activities was found between the two genotypes. It was interpreted that fitness difference between the two genotypes was small and treatment duration was too short or extent of ambient organic pollution was too low to lead to differential responses. Other environmental factor effects on activities of superoxide dismutases can also explain the results.     

5个中国人群Y染色体上17个双等位基因位点的多态性分析

选取Y染色体非重组区上17个双等位基因位点,利用ASPCR和PCR的方法对云南的怒族、傈僳族、纳西族、青海的撒拉族和福建的畲族进行了检测分型,确定了每一个体由这17个位点所构成的单倍型,并与国内其它20个民族群体的结果一起进行了主成分分析.结果显示,YAP、M15、M89、M9、M119、M95、M88、M45、M122、M134、M17、M120等12个位点在5个民族群体中均有不同的频率分布,其余5个位点没有发现多态变异,其中M122(C)在怒族、傈僳族、纳西族、撒拉族和畲族中的频率分别是82.1%、31.6%、5.9%、20%、69.3%;YAP 只在撒拉族中有2.2%的频率;傈僳族的M95(T)的频率最高,达68.4%.5个群体中共发现了12种单倍型,单倍型频率主要集中分布在H5、H6、H8、H11和H12,各民族群体的单倍型有各自的分布特点.主成分分析的结果显示:傈僳族则与苗瑶、侗壮语族的民族群体聚到了A簇;畲族、怒族与汉族群体紧密,聚到了B簇;而撒拉族、纳西族则与藏缅语族和阿尔泰语系的民族群体聚为C簇.图1表2参20