生物基包膜抑制型尿素对土壤温室气体排放及小青菜产量的影响

为研究生物基包膜氮肥对土壤温室气体排放及小青菜(Brassica chinensis)产量的影响,采用密闭式静态箱-气相色谱法测定盆栽试验条件下施用不同类型包膜尿素对土壤温室气体的排放特征,探究不同类型包膜尿素对土壤温室气体排放综合增温潜势(GWP)、排放强度(GHGI)及小青菜产量的影响。结果表明:抑制型尿素(I)、生物基包膜尿素(CRU)、生物基包膜抑制型尿素(CIRU)能够显著降低N_2O、CO_2、CH_4 3种温室气体的累积排放量。与普通尿素(U)相比,处理I、CRU和CIRU的N2O累积排放量显著降低了20.79%～79.52%,CO_2的累积排放量显著降低了46.53%～62.24%,CH4的累积排放量显著降低了25.38%～30.11%。与处理U相比,处理I、CRU和CIRU的GWP分别显著降低了40.44%、60.66%和65.02%;温室气体GHGI与GWP呈现出同样的趋势,处理I、CRU和CIRU分别显著降低了26.32%、70.53%和78.95%。与其他处理相比,处理CIRU具有最优的温室气体减排效果。处理CIRU的小青菜产量最高,为1 960.00 kg·hm~(-2),较处理U显著增产68.00%。研究表明,生物基包膜抑制型尿素在提高小青菜产量的同时还可以减少菜地温室气体排放及氮素气态损失。     

甘蓝型油菜BnWRKY41的理化性质分析及BnWRKY41-2在花青素合成中的功能解析

甘蓝型油菜BnWRKY41-1通过负调控花青素合成相关基因的表达而显著抑制拟南芥叶片花青素的积累。为深入了解同源拷贝BnWRKY41-2在花青素合成过程中的作用,对BnWRKY41-1和BnWRKY41-2进行生物信息学分析,并从甘蓝型油菜品种‘中双11’中成功克隆BnWRKY41-2的全长编码序列,分别转化烟草和拟南芥 wrky41-2突变体,对其亚细胞定位和在花青素合成中的调控作用进行分析。结果表明,BnWRKY41两个拷贝均具有典型WRKY结构域,N端不含跨膜结构和信号肽,二级结构主要由无规则卷曲组成,蛋白质修饰以磷酸化为主。BnWRKY41-2定位在细胞核中,在拟南芥 wrky41-2突变体背景下异源表达 BnWRKY41-2 基因使突变体叶片中的花青素含量恢复到野生型水平,而且可显著调控花青素积累相关基因的表达。这些结果表明BnWRKY41-2与BnWRKY41-1在蛋白质结构及理化性质方面相似,并且在调控拟南芥叶片花青素积累方面发挥类似的生物学功能,起负调控作用。     

硅酸盐对污染土壤铬、铅形态和小白菜吸收分布及其健康风险的影响

为保障蔬菜的品质安全,通过土壤盆裁试验,研究硅酸盐对Cr、Pb单一污染及Cr-Pb复合污染土壤中小白菜(Brassica chinensis)的生物量、土壤中Cr、Pb形态及小白菜体内Cr、Pb积累量的影响.结果表明,在受到较高水平的Cr～Pb污染时,小白菜对Pb的富集能力要明显高于Cr,被小白菜吸收的Cr、Pb都主要累积在根部.施用硅酸盐能通过减少土壤中有效态Cr、Pb的含量,从而减少小白菜对Cr、Pb的吸收,且施用效果明显,其中2.0 g/kg效果最好,但该处理严重抑制小白菜生长,不适于生产应用.而Si_1处理(1.00 g/kg)能在不影响产量的前提下极显著地降低小白菜茎中Cr、Pb的质量分数,并使叶中Pb的质量分数降至国家标准限量值附近或低于限量值,因此该处理在生产上极具应用前景.     

石灰、活性炭对镉污染土壤的修复效果研究

通过模拟铬(Cr,0～300 mg kg-1)污染土壤盆栽试验,研究石灰、活性炭及石灰+活性炭对铬胁迫下小白菜生长状况的影响及对铬污染土壤的修复效果。结果表明:受铬污染的土壤明显使小白菜受到毒害,但经石灰(L1、L2)、活性炭(C2、C3)及石灰+活性炭(L1C1、L2C2)处理均缓解了重金属的毒害症状,显著促进小白菜的生长,生物量较对照提高1～2倍(p<0.05)。3种改良剂相比,在相同Cr浓度处理下,活性炭对降低污染土壤中有效态铬的效果最好,与CK相比,有效态铬的含量降低至0.086 mg kg-1,降幅达77.36%。相关分析表明:小白菜叶部铬含量和根部铬含量与土壤有效态铬含量表现出显著的正相关(p<0.01),土壤pH与土壤有效态铬含量之间呈负相关(p<0.05),所以在铬污染的土壤中,可以提高土壤的pH,以减小土壤铬的植物有效性,使其向植物迁移的风险减小。     

钙镁磷肥的活化机理及其肥效研究

本文采用四种不同的活化剂(WZ、SMS、MSN、FM)对钙镁磷肥进行活化处理,通过红外光谱和菜心盆栽试验,分别探讨了活化钙镁磷肥的活化机理及其肥效。红外光谱分析表明,四种活化钙镁磷肥中的HPO42-特征吸收峰的透过率明显降低,说明它们的HPO42-含量均有不同程度的增加,而且由活化剂SMS和FM分别制得的活化钙镁磷肥(SMSCMP、FMCMP)出现了新的HPO42-特征吸收谱,使其中的磷向有效态转变。菜心盆栽试验表明,与钙镁磷肥相比,活化钙镁磷肥的生物量均提高,最高增幅达20.0%,植株的磷、镁含量均显著提高,吸磷量的增幅为4.8%～24.3%,减少了磷的流失;同时活化钙镁磷肥增加了土壤有效磷含量,后效足。     

GENOTYPIC DIFFERENCES IN ROOT MORPHOLOGY AND PHOSPHORUS UPTAKE KINETICS IN BRASSICA NAPUS UNDER LOW PHOSPHORUS SUPPLY

Application of phosphorus (P) fertilizer is important in crop production because of the low bioavailability of phosphorus to plants in both acidic and calcareous soils. Although rapeseed (Brassica napus) is generally sensitive to P deficiency, different cultivars differ widely in this respect. Differences in P uptake and utilization between two rapeseed cultivars, one P-efficient (‘97081’) and one P-inefficient (‘97009’), were evaluated in solution culture by studying the changes in root morphology and parameters of P uptake kinetics in response to low-P stress. The P-efficient cultivar had lower Km and Cmin values and higher Vmax and developed longer and denser lateral root hair with greater number of root tips and branches under low-P stress, which resulted in a better developed root system and more efficient uptake of P. That, in turn, led to higher concentration and accumulation of P in the plants, culminating in higher biomass production. However, P utilization efficiency (biomass production per unit P accumulated in plant) of the P-efficient ‘97081’ was lower than that of ‘97009’ when P was deficient. These results suggest that P efficiency in rapeseed is due to a better developed root system as well as efficient uptake of P.     

Zinc exposure has differential effects on uptake and metabolism of sulfur and nitrogen in Chinese cabbage

Zinc (Zn) is a plant nutrient; however, at elevated levels it rapidly becomes phytotoxic. In order to obtain insight into the physiological background of its toxicity, the impact of elevated Zn²⁺ concentrations (1 to 10 μM) in the root environment on physiological functioning of Chinese cabbage was studied. Exposure of Chinese cabbage (Brassica pekinensis) to elevated Zn²⁺ concentrations (≥ 5 μM) in the root environment resulted in leaf chlorosis and decreased biomass production. The Zn concentrations of the root and shoot increased with the Zn²⁺ concentration up to 68‐fold and 14‐fold, respectively, at 10 μM compared to the control. The concentrations of the other mineral nutrients of the shoot were hardly affected by elevated Zn²⁺ exposure, although in the root both the Cu and Fe concentrations were increased at ≥ 5 µM, whereas the Mn concentration was decreased and the Ca concentration strongly decreased at 10 µM Zn²⁺. The uptake and metabolism of sulfur and nitrogen were differentially affected at ≥ 5 µM Zn²⁺. Zn²⁺ exposure resulted in an increase of sulfate uptake and the activity of the sulfate transporters in the root, and in enhanced total sulfur concentration of the shoot, which could be ascribed partially to an accumulation of sulfate. Moreover, Zn²⁺ exposure resulted in an up to 6.5‐fold increase in water‐soluble non‐protein thiol (and cysteine) concentration of the root. However, nitrate uptake by the root and the nitrate and total nitrogen concentrations of the shoot were decreased upon Zn²⁺ exposure, demonstrating the absence of a mutual regulation of the uptake and metabolism of sulfur and nitrogen at toxic Zn levels. Evidently, elevated Zn²⁺ concentrations in the root environment did not only disturb the uptake, distribution and assimilation of sulfate, it also affected the uptake and metabolism of nitrate in Chinese cabbage.     

Effects of different levels of soil salinity on yield attributes,accumulation of nitrogen,and micronutrients in Brassica spp.

The present study was conducted to assess the effect of soil salinity on yield attributes as well as nutrient accumulation in different plant parts of seven Brassica cultivars from two different species raised in pot culture experiment with two levels of salinity treatments along with control corresponding to soil electrical conductivity (EC) values of 1.65 (S₀), 4.50 (S₁) and 6.76 (S₂) dS m^?1. The experiment was consisted of twelve replications in a completely randomized design. Imposition of salinity stress affected various yield attributing characters including plant height, which ultimately led to severe yield reduction. However, tolerant cultivars, CS 52 and CS 54 performed better under salt treatment showing lesser yield loss. Salinity stress reduced the nitrogen (N) content in leaves of the Brassica plants, which reflected in decreased seed protein content. Reduced accumulation of iron (Fe), manganese (Mn) and zinc (Zn) was observed in leaf, stem and root at flowering and post-flowering stages, while CS 52 and CS 54 showed less reduction than susceptible cultivars under salinity stress.     

大白菜InDels标记开发及其在剩余杂合体鉴定中的应用

大白菜(Brassica rapa ssp.pekinensis)参考基因组序列的公布及测序成本的降低为大规模开发插入/缺失(Insertion/Deletion,InDel)标记提供了可能.本研究以性状差异明显的大白菜自交系He102与06-247为亲本,开展了全基因组重测序、标记开发和验证工作.二者测序深度分别为10×和8×,经筛选共获得330 218个InDels差异位点,出现频率为1.2个/kb,其中有11 238个差异位点位于编码区,包括5 184个差异基因,每个基因平均包含2.2个差异位点.分别以He102与06-247测序数据中筛选出的多态性InDels位点为参照,从10条染色体上随机选择933个位点进行了PCR扩增及电泳检测验证.结果表明,测序深度对假阳性率有直接影响,以测序较深的材料中筛选到的差异位点为参照,其验证结果的假阳性率亦较高,反之则较低.本研究中以He102与06-247为参照选择InDels位点验证的平均假阳性率分别是51.9％和22.5％.从933个位点中共筛选出593个在亲本之间实际表现为多态性的位点,这些差异位点中有375个位于编码区,是潜在的功能性标记.利用上述差异位点,检测了He102与06-247衍生的F7代重组自交系群体,明确了F7代各株系在593个位点的纯/杂合状态,为利用剩余杂合株系精细解析和精准定位大白菜耐抽薹、抗病毒、抗干烧心等重要农艺性状奠定了基础.     

用EST—SSR分子标记技术构建大白菜核心种质及其指纹图谱库

摘要利用EST-SSR分子标记对大白菜种质资源基因库中686份样品所代表的1900份大白菜种质资源进行分析研究。构建大白菜种质资源的核心种质并且形成核心种质的EST—SSR指纹图谱库。结果表明利用4组鉴定白菜品种的EST—SSR的特异性标记组合,获得近158个EST—SSR多态的标记,对大白菜种质资源基因库中686份样品所代表的1900份大白菜种质资源进行核心种质的构建提供了分析数据。形成的核心种质包括168份样品,占库存资源的8．8％,它的多态位点百分率保持了原群体的100％。所构建的核心种质涵盖了原资源的绝大部分区域来源的品种,包含了早、中、晚熟品种中所有典型的大白菜类型和其相关的特征特性。并进一步进行了核心种质资源遗传多样性分析。核心种质的EST—SSR指纹图谱库中,每一份样品的指纹都是唯一的,为登记、评价、整理、分发、繁殖等种质资源库的管理和育种者对其材料的利用提供了重要的有价值的信息。EST-SSR标记组合是构建中国大白菜核心种质及其指纹图谱的经济、高效的方法。