土壤硒对油菜含硒量、生长和产量的影响

应用上培盆栽试验,研究了土壤不同硒水平对油菜生长和产量的影响以及油菜不同时期各器官含硒量。结果表明:(1)土壤加硒至15—20ppm时,油菜出现中毒。(2)随土壤硒含量增加,油菜各器官硒含量成倍增加,表明油菜富硒特点明显。(3)油菜籽中硒主要分配到菜籽饼内,菜籽油的硒含量相对较少。     

甘蓝型油菜亲本基因型对其与埃塞俄比亚芥的可交配性影响

以10个甘蓝型油菜品种与埃塞俄比亚芥进行了正反杂交。结果表明,甘蓝型油莱与埃塞俄比亚芥的种间可交配性很低,但在反映可交配性强弱的各个性状上,基因型间的差异显著。甘蓝型油菜作母本时,受精频率和结角率都较反交为低,在获得杂种种子和杂种植株上明显优于反交。约2/3的甘蓝型油菜×埃塞俄比亚芥低生活力杂种种子在组织培养条件下能萌发形成植株,反交的萌发率几乎为零。甘蓝型油菜×埃塞俄比亚芥的F_1植株能与甘蓝型油菜回交,与埃塞俄比亚芥回交不亲和。由于种间杂种F_1植株群体中常出现大量的母型植株,且获得的真杂种种子出苗率又很低,因此提出以F_1杂种植株数为基准的可交配指数来衡量种间可交配性高低。     

提高油菜游离小孢子胚诱导频率的研究

以11个甘蓝型油菜基因型为材料,采用NLN培养基进行游离小孢子培养,对如何提高可培养的基因型范围和产胚率进行了研究。结果表明,11个油菜基因型中有10个基因型可以诱导出胚,培养成功率达90.9%,表明采用NLN培养基进行游离小孢子培养油菜基因型范围比较宽,但各基因型间小孢子胚产量差别很大,每花蕾产胚量为0.08~3.53个,TR4和TR9两个基因型每花蕾产胚可达3.23,3.53个。以TR4和TR9两个基因型为试材,进一步改进培养基和培养方法,采用NLN培养基中添加激素和活性炭方法,可大大提高产胚率,产胚量分别达到7.11和10.05个/蕾;接种后,小孢子经33℃高温预处理可显著影响产胚量。子叶形小孢子胚在光下适当培养后转入B5 BA 0.2 mg/L NAA 0.02 mg/L继代培养基上,大多数胚能长成绿芽,B5 6-BA 0.2 mg/L 3%蔗糖 1%琼脂培养基有利于小孢子胚长成植株。     

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.     

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.     

草除灵对甘蓝型油菜苗期生理生化及超微结构的影响

为探明草除灵作用的生理机制及其胁迫下不同甘蓝型油菜品种的耐性差异机制,以浙大619、浙大622为试验材料,对苗期油菜叶面喷施不同浓度的草除灵,采用生理生化分析方法、叶绿素荧光技术和超显微技术,探究草除灵对甘蓝型油菜苗期生理生化特性以及超微结构的影响。结果表明,低浓度(2.5 g·L~(-1))的草除灵对2个油菜品种的生长无显著影响,当草除灵浓度大于5.0 g·L~(-1)时,随着处理浓度的升高,油菜生长受抑制的程度逐渐增加,净光合速率、叶绿素含量和叶绿素荧光值显著下降,抗氧化酶系统的活性降低,膜脂过氧化加剧,活性氧积累增多,叶绿体、线粒体等叶肉细胞超微结构受损,且浙大619的抗草除灵胁迫能力高于较敏感品种浙大622。因此,本研究明确了草除灵对甘蓝型油菜安全性的影响,这对该除草剂的田间推广应用具有重要意义。     

木霉菌M2的鉴定及其对小白菜促生效果研究

以一株分离自健康、高产辣椒根际土壤的木霉菌(Trichoderma spp.)M2为供试菌株,研究其对小白菜生长发育的影响并在形态学分类的基础上结合r DNA-ITS序列分析的手段,对木霉菌M2进行分类鉴定,以期为微生物肥料的开发提供优良菌种。将木霉菌M2进行固体发酵制得孢子粉,研究其在温室条件下是否对小白菜的生长具有促生能力。结果表明:菌株M2属于哈茨木霉(Trichoderma harzianum);在温室盆栽试验中,土壤接种M2孢子粉对小白菜具有不同程度的增产作用,且能够提高叶绿素含量、可食用叶片数,其中接种5.0×10~9cfu的M2孢子粉处理的鲜重、干重最高,比对照组分别增加30.26%、20.08%;接种5.0×10~8cfu的M2孢子粉处理鲜重、干重较对照组分别增加18.33%、12.46%。这说明哈茨木霉M2菌株对小白菜的增产效果明显,具有潜在的农业应用价值。     

少花龙葵种间嫁接后代对小白菜生长及镉积累的影响

通过盆栽试验,将茄子、土豆、番茄作为砧木嫁接的少花龙葵后代与小白菜混种,研究了镉胁迫条件下(10 mg kg~(-1)),少花龙葵种间嫁接后代对小白菜生长及镉积累的影响。结果表明:混种少花龙葵种间嫁接后代均能提高小白菜的生物量和叶绿素含量,其大小顺序均为:混种茄子砧木的少花龙葵嫁接后代混种土豆砧木的少花龙葵嫁接后代混种未嫁接少花龙葵混种番茄砧木的少花龙葵嫁接后代单种。同时,混种少花龙葵种间嫁接后代也能提高小白菜根系镉含量、地上部分镉含量及整株镉含量。混种小白菜后,番茄砧木嫁接的木少花龙葵后代的地上部分生物量、地上部分镉含量及地上部分镉积累量较未嫁接少花龙葵均有所提高,分别较未嫁接少花龙葵提高了7.73%、7.54%和15.84%,其余的处理则提高不明显或低于未嫁接少花龙葵。因此,少花龙葵不适合混种镉污染条件下的小白菜,但番茄作为砧木嫁接的少花龙葵后代能够提高少花龙葵对土壤镉污染的修复能力。     

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.     

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。