甘蓝型油菜硼营养高效的遗传分析

利用土壤有效硼缺乏的田间小区试验 ,研究甘蓝型油菜硼营养高效品种和低效品种间 2个杂交二代群体及其回交一代硼营养性状的分离规律。结果发现 ,硼营养高效受一对主效基因控制。在缺硼胁迫下 ,硼高效性状与抽薹天数和生育天数之间紧密连锁 ,生育期 (抽薹天数和生育天数 )可作为甘蓝型油菜硼高效种质筛选及其杂种后代硼效率鉴定和选育的参考指标。     

不同硼效率甘蓝型油菜苗期对硼镁营养的反应

利用溶液培养研究硼低效和高效甘蓝型油菜(Brassica.napus)苗期对硼镁营养的反应。结果表明,低硼浓度下提高镁时,油菜的生长受影响不大,硼含量和累积量降低,镁含量和累积量及叶绿素上升。低镁浓度下提高硼时,油菜镁含量、镁积累量降低,且硼低效品种降低幅度大于硼高效;叶绿素降低幅度则硼高效大于硼低效品种。高硼浓度下提高镁时,硼镁含量和累积量及叶绿素含量均提高,提高幅度为硼高效品种大于低效品种。高镁浓度下提高硼时,硼镁表现出显著的相互促进,硼高效品种促进效应大于低效品种。在很大程度上镁影响油菜叶绿素a的含量,而硼影响油菜叶绿素b的含量。硼镁营养对锌含量无大的影响;在低镁浓度下,油菜低效品种锰含量显著增加。无论是低镁或高镁浓度下提高硼,硼高效和低效品种铁含量均有所增加,低效品种增加显著。     

甘蓝型油菜硼高效基因等位性检测

甘蓝型油菜 8Z05和青油 10号为硼高效品种 ;Bakow 为硼低效品种。 2000～2001年度 ,硼高效品种 8Z05青油 10号F2代 588个单株种植在缺硼土壤上。花期调查缺硼症状 ,表现硼高效的单株数与硼低效的单株数之比为 574∶14 ;结实期分离规律与花期相似。这说明甘蓝型油菜硼高效品种 8Z05和青油 10号硼营养高效主效基因是等位的 ,同时可能存在微效基因的修饰作用 ,但微效基因的QTL可能不完全相同。 2个年度的试验结果一致。     

硼镁营养对不同硼效率甘蓝型油菜品种苗期硼形态的影响

通过营养液培养试验,研究硼镁对不同硼效率甘蓝型油菜品种苗期硼形态的影响。结果表明,硼正常时,硼高效品种青油10号自由态和半束缚态硼含量较低效品种高,能参与转运的硼较多;硼低效品种95105束缚态(细胞壁)硼含量较高,自由态和半束缚态硼含量较低,转运、利用效率低。低硼时,硼高效品种根部束缚态硼减少,自由态和半束缚态硼增加,而叶中各形态硼分配合理,达到优化利用;反之,硼低效品种适应营养胁迫的能力较高效品种差。镁在一定程度上可以使硼向有利于其移动的形态转化,提高硼库容量,但在低硼、低镁时,却减少硼低效品种硼库容量,加剧地上部硼的缺乏。     

硼对不同硼效率甘蓝型油菜品种细胞壁组成的影响

采用营养液培养技术 ,研究B对不同B效率油菜品种细胞壁组成的影响。结果表明 ,根系细胞壁提取率及细胞壁纤维素含量高于叶片 ,果胶含量低于叶片 ,半纤维素含量和叶片差异不大。缺B使细胞壁提取率升高 ,但对根系和叶片细胞壁组成的影响不显著。不同B效率油菜品种细胞壁组成在根系和下部叶中差异不大 ,上部叶片高效品种螯合剂可溶性果胶含量显著高于低效品种 ,碱溶性果胶含量显著低于低效品种 ;半纤维素和纤维素含量及果胶总量差异不大     

不同硼效率甘蓝型油菜品种中硼的形态及其相互关系

采用硼高效 (9589,9590)和硼低效 (9141,95105)甘蓝型油菜品种各 2个及其 4个杂交种 (95105 9589,95105 9590 ,91419589,9141 9590)作试材 ,研究了不同硼效率甘蓝型油菜品种及其F1代花期各部分叶片中硼的形态。结果表明 ,在B2 (0 .35mg/kg)处理下 ,硼高效品种上叶 ,中叶 ,下叶和花中水溶态硼含量和束缚态硼含量低 ,半束缚态硼含量高 ,而硼低效品种 3种硼形态的含量则与此相反 ;F1代基本居于二者之间 ,且趋向于高效品种 ;在B1(0 .2 0mg/kg)处理下 ,各叶片和花中各硼形态含量也呈现类似的特征 ,但存在例外 ,尤其在花中。B1和B2处理下 ,除B1处理上叶外 ,硼高效品种和F1代的花和叶片中水溶态硼和束缚态硼相对含量较低 ,半束缚态硼相对含量较高 ,硼低效品种与此相反。建立了硼形态之间的相互平衡关系 ,并把这种平衡关系同硼效率联系起来 ,表明硼形态和硼效率存在密切关系 ,可望由此揭示不同甘蓝型油菜品种硼效率差异的生理机制。     

不同硼效率甘蓝型油菜基因型对镁的吸收,分配差异的研究

在土培条件下,研究了不同硼效率甘蓝型油菜基因型镁的吸收、分配以及硼镁关系。结果表明,镁的吸收、分配及镁硼比值等存在基因型差异,硼对镁有一定影响。镁含量高效品种〈低效品种,镁吸收量高效品种〉低效品种,提高硼水平,镁含量下降,吸收量增加。在镁的分配、运转能力上,高效品种〉低效品种,且硼对高效品种的促进作用较大。镁硼比值为高效品种〈低效品种,镁硼比值Ｂ１〉Ｂ２〉Ｂ３。     

不同硼效率甘蓝型油菜品种悬浮细胞的硼钙营养效应

采用细胞培养的方法 ,研究了培养基中硼钙营养水平变化对不同硼效率甘蓝型油菜品种悬浮细胞生长及硼、钙和镁含量的影响。结果表明 ,增加硼营养显著促进了悬浮细胞的生长 ,钙对悬浮细胞生长的影响因硼供应状况和品种而异。两品种间差异表现为 ,低硼的抑制效应、高硼的促进效应以及较高钙的抑制效应都是硼低效 (对缺硼敏感 )品种Bakow(原代号 9141,曾用代号 01)比硼高效 (对缺硼不敏感 )品种特早 16 (原代号 9118,曾用代号 03)明显。增硼显著降低悬浮细胞的钙含量 ;镁含量因增硼先上升而后下降。增钙对悬浮细胞中硼含量无显著影响 ,硼钙镁之间存在着复杂的关系。     

低硼对甘蓝型黄籽油菜与黑籽油菜花期生理特性的影响

为探索甘蓝型黄籽油菜与黑籽油菜花期相关生理特性对低硼的响应差异,以2个具有相同遗传来源的黄籽(L1)和黑籽(L2)油菜基因型为材料,研究了田间条件下低硼处理对甘蓝型黄、黑籽油菜花期部分生理特性的影响。结果表明,低硼处理后黄籽油菜下部叶片中养分的再利用能力降低,而黑籽油菜仍有一定的养分可供利用;无论黄籽油菜还是黑籽油菜,低硼处理均使其花器官形态变小,干重下降,低硼对黄籽油菜雌雄蕊长度的影响大于黑籽;甘蓝型黄、黑籽油菜的花粉活力在低硼处理后明显降低,但黄籽油菜无活力花粉的比率明显高于黑籽油菜;低硼使甘蓝型油菜雄蕊和雌蕊中的可溶性糖、淀粉、游离脯氨酸以及可溶性蛋白质含量降低,黄籽油菜的降低幅度明显大于黑籽油菜。与相同遗传来源的黑籽油菜相比,甘蓝型黄籽油菜花期的相关生理特性更易受低硼的影响。     

对缺硼反应没的油菜品种根系生长特性研究

在营养液培养、根箱土培和组织培养条件下,研究了不同油菜品种根系生长变化动态。结果表明,缺硼明显降低根系长度,尤其抑制根尖伸长,且与品种间缺硼敏感性密切相关,即对敏感品种的抑制程度高于不敏感品种。     

硼对甘蓝型油菜蛋白质的影响

利用比色法和聚丙烯凝胶电泳法分析了不同硼营养状况下甘蓝型油菜的幼苗叶片及开花期花药内可溶性蛋白质含量及组分的变化。结果表明,缺硼或硼过量部会造成幼苗叶片及花药内蛋白质含量显著下降;从电泳图谱中也可看出,可溶性蛋白质的组分也发生了变化。不适当供硼(缺硼或硼过量)幼苗叶片及花药内所测的大部分蛋白质含量减少,有个别的蛋白质增加或缺失。     

硼对油菜花器官发育和结实性的影响

在缺硼和正常供硼条件下，油菜花器官的含硼量明显高于叶片，尤其是雌蕊和雄蕊中的含量可达同期叶片的两倍左右；硼过量时则以叶片含硼量最高。缺硼导致雄蕊长度，干重下降，花药绒毡层异常，花粉囊化化受阻。缺硼和硼过量均使油菜单株有效角果数，每角果籽粒数及结角率，结籽率，油菜籽产量下降。硼对角果的胚珠数没有影响。与宁油７号相比，宁油８号油菜品种更易受缺硼和过量硼的影响。     

STUDIES ON DIFFERENCES OF NITROGEN EFFICIENCY AND ROOT CHARACTERISTICS OF OILSEED RAPE (BRASSICA NAPUS L.) CULTIVARS IN RELATION TO NITROGEN FERTILIZATION

Differences of nitrogen efficiency of oilseed rape (Brassica napus L.) cultivars and their physiological properties were studied in a pot experiment, and the ratio of seed yield with no nitrogen supplied to that with normal nitrogen supply was adopted as a nitrogen efficiency coefficient. Results showed that the nitrogen efficiency coefficient determined for eight oilseed rape cultivars varied from 0.37 to 0.69, the ratio of nitrogen uptake amounts per plant, nitrogen transfer velocity from stems and leaves to seeds, and nitrogen physiological efficiency of oilseed rape cultivars under nitrogen stressed condition differed from with normal nitrogen supply. The higher the nitrogen efficiency of a cultivar, the higher the ratio of N uptake in no nitrogen to with N supplied. Under low nitrogen-supplying conditions, high nitrogen efficiency cultivars had longer roots, more lateral roots, higher amounts of reuse of nitrate from stem and leaves, and higher nitrate reductase activities in leaves.     

EFFECT OF BORON-DOPED GOETHITE ON SOIL ACIDITY,DIFFERENT FORMS OF MANGANESE IN RED SOIL AND THE GROWTH OF RAPE (BRASSICA NAPUS L.) SEEDLINGS

Rape (Brassica napus L.) seedling pot experiments were performed with a red soil treated with goethite which had boron (B) either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Soil acidity, different forms of manganese in the soils and different elements content of the rape seedlings were determined. It was found that the addition of boron-containing goethite to the soils resulted in increased rape growth, elevated soil pH and decreased exchangeable acidity. Compared with the control, boron-containing goethite elevated the content of exchangeable manganese (Mn) (EXC-Mn), organic matter bound Mn (OM-Mn), reducible oxide Mn (RO-Mn) and residual Mn (RES-Mn) which were difficult to use for plant. Low labile organic matter was significantly correlated with easily reducible oxide Mn (ERO-Mn) (P < 0.01) and RO-Mn (P < 0.05). Middle organic matter and soil pH was significantly (P < 0.05) correlated with RES-Mn. Stepwise regression was used to select the combination of variables that best estimates shoot and root dry weight of rape seedling. Among them, soil pH, EXC-Mn, OM-Mn, RO-Mn and RES-Mn significantly influenced the dry weight of rape seedlings. The addition of boron-containing goethite improved the uptake of iron (Fe), calcium (Ca), magnesium (Mg), and copper (Cu) element and decreased the uptake of Mn and zinc (Zn) element in rape seedling. The results suggested that boron-containing goethite could provide a better soil acidity environment for plant growth; it was also an important agent increasing a part of manganese difficult to use for plant and reducing the activity of soil manganese, which was beneficial to altering rape seedling growth.     

INHERITANCE OF RESISTANCE TO IRON DEFICIENCY CHLOROSIS IN CHICKPEA (CICER ARIETINUM L.)

Iron (Fe)-deficiency chlorosis causes considerable yield losses in chickpea (Cicer arietinum L.) when susceptible genotypes are grown in calcareous soils with high pH. The most feasible method for alleviating Fe deficiency is the selection of suitable cultivars resistant to Fe deficiency chlorosis. ICC 6119 (desi type), which is Fe-deficient chlorosis, was crossed with CA 2969 and Sierra (kabuli types), resistant to Fe deficiency chlorosis. Inheritance of resistance to Fe deficiency in chickpea revealed that the resistance was controlled by a single dominant gene in these genotypes crossed. A negative selection for resistance to Fe deficiency chlorosis will be effective after segregating generations.     

航天诱变对甘蓝型油菜根尖的细胞学效应

对经卫星搭载的甘蓝型油菜不育系及保持系种子当代(SP1)根尖细胞进行了细胞学研究。结果表明,与未搭载对照相比,航天诱变对多数甘蓝型油菜种子根尖细胞的有丝分裂产生了促进效应,同时使根尖细胞产生了较高频率的染色体畸变和微核。分析表明,通过卫星搭载,甘蓝型油菜种子在细胞学水平上发生了真实的诱变效应。与不育系材料相比,航天搭载对保持系材料有着更强的诱变作用。     

INCREASING SAR OF IRRIGATION WATER AGGRAVATES BORON TOXICITY IN MAIZE (ZEA MAYS L.)

We evaluated the effect of boron (B) application on shoot growth and shoot B concentration and uptake by two maize cultivars (‘FHY-396’ and ‘Sonari’) on a loam soil irrigated with water of different sodium absorption ratio (SAR) values [control, 5 and 15 (mmol_c L^?1)^1/2]. Plants were harvested after forty days of growth. Shoot dry matter decreased significantly (P < 0.05) with B application due to toxicity marked by leaf injury. Toxic effect of B was further aggravated by increasing SAR of irrigation water. In both cultivars concentration and uptake of B was significantly (P < 0.05) increased over control with B application and SAR of irrigation water. Shoot Ca concentration decreased with increasing SAR and B application. The phenomena of B toxicity and low Ca marked by reduction in shoot dry matter of plants irrigated with high SAR water could be important in management of brackish water used for irrigating crops on arid and semiarid region soils.     

ADAPTABILITY MECHANISM OF NITROGEN-EFFICIENT GERMPLASM OF NATURAL VARIATION TO LOW NITROGEN STRESS IN BRASSICA NAPUS

Previous studies showed that wide genotype differences in nitrogen (N) efficiency exists among cultivars of rapeseed (Brassica napus L.), but the mechanisms behind those differences are still unknown. In the present study, our aim was to analyze the adaptability mechanism of N-efficient rapeseed to low-N stress by employing two genotypes of natural variation in N efficiency. Nitrogen-efficient genotype, ‘BG51’, and N-inefficient genotype, ‘BG88’, were grown in a solution culture experiment under conditions of high-N (6.0 mM N) and low-N (0.6 mM N) supply. After growing 30 d, roots and shoots were sampled for the analysis of dry weight, N concentration and accumulation, N use efficiency (NUE), N transport efficiency (NTE), root system vigor parameters, nitrate redutase (NR) activity, and glutamine synthetase (GS) activity. Nitrogen deficiency decreased shoot and root dry weight significantly, but ‘BG51’ exhibited a significantly lower decrease in shoot dry weight and had significantly higher biomass production than ‘BG88’. Under low N supply ‘BG51’ accumulated more N in shoot, root and whole plant than ‘BG88’, and presented higher NUE in both shoot and root. Low-N stress induced an increase in maximum root length by 28.3% for ‘BG88’ and 55.1% for ‘BG51’ compared with the high-N treatment. And ‘BG51’ presented larger root volume, higher root vigor, larger root total absorbing area and root active absorbing area than ‘BG88’ in low-N treatment. Furthermore, ‘BG51’ had significantly higher NR and GS activity in both leaf and root in low N treatment than ‘BG88’, while there was no evident difference between them in high N treatment. These results suggested that N-efficient rapeseed germplasm of natural variation involves an integrated adaptability mechanism responding to low-N stress. Namely, N-efficient genotype could form more developed root system to accumulate more N, and presented efficient N assimilation by higher NR activity and GS activity than N-inefficient genotype. These ultimately resulted in high tolerance of N-efficient genotype to low-N stress and high biomass production.     

EFFECT OF EXTERNAL NITRATE CONCENTRATIONS ON NITRATE EFFLUX FROM ROOTS AND ACCUMULATION IN TWO BRASSICA NAPUS L. CULTIVARS

The nutrient solution was replaced on day 72 after sowing, and then the relationship between nitrate (NO₃)-nitrogen(N) concentration in plants and nitrate efflux from roots of two oilseed rape cultivars (Brassica napus L. cv. ‘Zhongyou 821’ (‘ZY821’) and “D89”) was compared on days 73, 74, and 75, respectively. Nitrate-N concentration in petioles of “ZY821” was significantly greater than in “D89”. Nitrate-N concentrations in the nutrient solution and petioles were high on day 73 and nitrate efflux from roots of “D89” was greater than from “ZY821”. On day 75, as nitrate-N concentrations in the nutrient solution declined, both the maximum cumulative efflux and efflux rate of “ZY821” was higher than “D89.” We hypothesized that “ZY821” could remobilize more nitrate-N from the petioles to meet its N needs. This would result in a decline in translocation of nitrate from roots to shoots and an increase in root cytoplasm nitrate concentrations and root efflux.     

EXPERIMENTAL LEACHING OF MACRONUTRIENTS FROM BRASSICA NAPUS L. INCREASES WITH LEAF AGE AND GROWTH STAGE

It was the aim of the present study to determine the mobile nutrient content in leaves and pods of oilseed rape in relation to leaf age and growth stage and to develop an instrument to estimate the possible significance for interpretation of plant analytical data. From older leaves an increasing amount of sulfur (S), potassium (K), magnesium (Mg), calcium (Ca), and phosphorus (P) was leached, while no N was extracted after 24 h of leaching. In younger leaves the potential for nutrient leaching was below 10% for all investigated nutrients while in older leaves this value increased to 58% for S, 28% for P, 21% for Mg, 18% for Ca and 16% for K. Generally the potential for nutrient leaching from leaves and pods increased with growth stage. Until BBCH 83 nutrient leaching from pods was very low with less than 5% for the investigated elements, except S, but increased with further ripening drastically.