烯效唑干拌种对小麦种子萌发过程中DNA合成的影响

以小麦品种绵阳 2 6为材料 ,利用3 H TdR掺入法 ,研究了烯效唑干拌种对小麦种子萌发过程中DNA合成的影响。结果表明 :烯效唑处理后 ,小麦种子萌发早期DNA合成加快 ,当浓度为 2 0mg kg时 ,DNA合成速率最快 ;同时 ,在小麦种子萌发早期烯效唑处理促进3 H 胸苷掺入可能反映了烯效唑有助于萌发中DNA修复和DNA复制 ,为种子萌发奠定了较好的基础。     

SPECIFIC ION EFFECTS ON THE SEED GERMINATION OF SUNFLOWER

Salinity can affect germination of seeds either by creating osmotic potentials that prevent water uptake or by toxic effects of specific ions. This work was carried out to evaluate the germination of sunflower (Helianthus annuus L.) seeds under increasing salinity by using the most abundant salts in China. Potassium (K⁺), sodium (Na⁺), and calcium (Ca²⁺) contents in hypocotyls were determined on the fifth day. At same concentration of salt solution, the adverse effect of ions is in the following sequence: carbonate radical (CO₃ ^2?) > sulfate radical (SO₄ ^2?), chloride (Cl^?) > bicarbonate radical (HCO₃ ^?), magnesium (Mg²⁺) > Ca²⁺, and Na⁺ > K⁺. The effect of salinity on the germination phase of development is mainly due to its osmotic component other than the ion toxicity. Calcium decreased as increasing of the concentration of salt solutions, and cannot act as the role of enhancing cell division and membrane permeability.     

DIFFERENTIAL GERMINATION AND DEVELOPMENTAL RESPONSES OF BLETIA PURPUREA (ORCHIDACEAE) TO MANNITOL AND SORBITOL IN THE PRESENCE OF SUCROSE AND FRUCTOSE

Orchid seeds are energy-limited at dispersal and require infection by fungi in situ or an exogenous carbohydrate source when grown in vitro. While they are able to utilize a wide range of carbohydrates, polyols (sugar alcohols) are not known to enhance germination and early seedling development. In this study, we examined whether two polyols, mannitol and sorbitol, are inhibitory to germination and development or simply not utilized during germination using Bletia purpurea as a model orchid. When seeds were cultured with germination-promoting sugars (sucrose and fructose), sorbitol had little or no effect on germination and slightly inhibited seedling development at high molarities. Seeds cultured in the presence of mannitol and sucrose or fructose at 1 and 10 mmol exhibited enhanced germination, seedling development and rhizoid production. Mannitol alone did not enhance germination over control. We hypothesize that mannitol is taken up by Bletia purpurea embryos, leading to reduced osmotic stress and allowing for enhanced production of dehydration-sensitive rhizoids.     

EFFECT OF NITRIC OXIDE ON ALFALFA SEED GERMINATION UNDER NaCi STRESS

以甘农4号、阿尔冈金2个品种苜蓿为材料,用一氧化氮（NO）供体硝普钠、NO清除剂c-PTIO、一氧化氮合酶抑制剂N-硝基．L-精氨酸甲脂、硝酸还原酶抑制荆钨酸钾及硝普钠类似物亚铁氰化钠（不产生NO）处理苜蓿种子,研究NO对盐胁迫下苜蓿种子萌发的生理效应。结果表明,盐胁迫显著抑制了2个苜蓿品种的发芽率、胚芽和胚根长及幼苗干重（P〈0．05）,降低种子萌发过程中α、β-淀粉酶、蛋白水解酶活性,抑制淀粉水解和可溶性糖积累（P〈0．05）;盐胁迫下添加外源NO则使2个品种苜蓿α、β淀粉酶、蛋白水解酶活性、种子发芽率显著提高（P〈0．05）,淀粉含量降低,可溶性糖含量升高、胚芽和胚根长及幼苗干重显著增加（P〈0．05）;NO供体SNP的类似物亚铁氰化钠对盐胁迫下苜蓿种子萌发的各项指标无明显影响;施用NO清除剂c-PTIO、硝酸还原酶抑制剂钨酸钾和一氧化氮合酶抑制剂N-硝基-L-精氨酸甲脂具有降低苜蓿种子萌发的效应（P〈0．05）。因此,盐胁迫抑制苜蓿种子的萌发,而添加外源NO是缓解这种抑制作用的有效途径,内源NO也可能参与盐胁迫下苜蓿种子萌发的调节,且通过NOS和NR途径产生的NO在缓解盐胁迫抑制苜蓿种子萌发中可能起关键作用。     

EFFECTS OF SOAKING TEMPERATURE,STRATIFICATION, POTASSIUM NITRATE AND GIBBERELLIC ACID ON SEED GERMINATION OF LOQUAT TREES

The present study was carried out to increase loquat seed germination with treatments consisting of two soaking temperatures (24 ± 2°C and 38 ± 2°C), chemical agents [control, 0.5% potassium nitrate (KNO₃) and 250 mgL^?1 gibberellic acid (GA₃) each for 20 h], and different moist chilling (MC) periods (1, 2, 3 and 4 weeks under 4–5°C). Compared with 24 ± 2°C, soaking at 38 ± 2°C reduced germination%, mean daily germination (MDG), and mean germination time (MGT), plumule and radicle lengths. Germination percentage, days to 50% emergence, fresh weight and lateral root numbers significantly reduced as MC period increased. KNO₃ and GA₃ had no significant effect on germination percentage, MDG, MGT and lateral root numbers. KNO₃ reduced days to 50% emergence and radicle length, but increased fresh weight compared with control and GA₃. Finally, our results suggest the soaking at 24 ± 2°C followed by 0.5% KNO₃ each for 20 h plus 1 week of MC or soaking at 24 ± 2°C followed by 250 mgL^?1 GA₃ each for 20 h plus 2 week of MC.     

模拟酸雨对杂交苏丹草种子萌芽及幼苗生长的影响

采用不同pH值的模拟酸雨对杂交苏丹草皖草2号进行处理,测定对其种子萌发和幼苗生长的影响。试验结果表明,酸雨会导致土壤酸化,pH值大于4.0的酸雨对杂交苏丹草种子的发芽和幼苗生长无不良影响,pH值低于4.0的酸雨对杂交苏丹草种子的发芽和幼苗生长具有抑制作用,且pH值越低,所产生的不利影响越大。     

类黄酮对AM真菌孢子萌发和早期生长的影响

研究了离体培养条件下Quercetin、Naringin、Rutin、Umbelliferon、Biochanin A、Zeatin Riboside、Fla-vanon、Apigenin、Genistein、Formononetin等10种类黄酮化合物对Gigaspora margarita和Glomus geosporum孢子萌发及菌丝发育的影响。结果表明,Quercetin、Rutin促进Gi.margarita早期发育,在0.5~8.0μmol L-1浓度范围,Quercetin对菌丝生长、菌丝分枝及辅助细胞形成促进作用明显,菌丝长度、菌丝分枝数及辅助细胞群与对照组相比提高到2~3倍,其他类黄酮对Gi.margarita孢子早期生长无明显影响。在一定浓度条件下,Formononetin、Genistein和Naringin促进Gl.geosporum孢子萌发、菌丝生长及分枝,Apigenin、Flavanon和Naringin刺激次生孢子的形成,而Biochanin A仅促进其孢子萌发。类黄酮对AM真菌孢子发育种属差异性影响取决于类黄酮种类及其使用浓度,不同的类黄酮分别在AM真菌孢子萌发、菌丝生长及菌丝分化等不同发育事件中参与作用。研究类黄酮对AM真菌早期发育的影响机制有助于理解微生物与植物之间的相互作用。     

卫星搭载处理对辣椒萌发过程中抗氧化酶活性的影响

测定经卫星搭载后的辣椒种子萌发过程中抗氧化酶的活性。结果表明:辣椒种子经卫星搭载处理后,其发芽势和发芽率分别比对照提高了3.5%和5.3%;在萌发过程中,可溶性蛋白质MDA含量低于地面对照,但SOD活性高于对照;卫星搭载的种子在萌发13d的幼苗体内SOD、G-POD、APX和CAT活性分别较对照提高了14.29%、25.23%、1.84%和21.52%。表明卫星搭载处理提高了辣椒种子和幼苗体内抗氧化酶活性,对萌发初期保护膜系统的修复具有重要的意义。     

~(60)Co-γ辐射对菜心种子萌发和幼苗生长的效应

用60 Coγ辐射预先浸泡 1h的菜心种子 ,结果表明辐射延缓了种子萌发 ,但不影响萌发率 ;幼苗的高度、根长、幼苗鲜重随剂量增大而受抑制 ,与存活率间呈显著的负相关 ;适宜的处理剂量为 2 0 0～ 30 0Gy。     

低能离子注入种子过程中的温度效应

本文用玉米干种子作为实验材料,设打印纸覆盖、铝箔覆盖和不覆盖3个处理,研究了在低能离子注入种子的过程中,温度对种子发芽率的影响。研究结果表明3个处理中不能传递热量的打印纸覆盖的种子发芽率最高,不覆盖的种子的发芽率其次,而可以传递热量的铝箔覆盖的种子发芽率最低。温度能够显著影响注入后种子的发芽,靶室内的高温总体上降低了种子的生活力。文中对离子注入时的温度效应做了校正,并给出了校正后的种子发芽曲线。     

硝酸镧浸种对水稻发芽和幼苗生长的效应

用不同浓度的硝酸镧溶液,处理汕优桂99(三系品种)、桂光一号(二系品种)和广桂110(常规品种)3个水稻品种的种子。结果表明:对汕优桂99和桂光一号有促进芽生长、抑制根生长的作用;对广桂110前期有促进根生长,后期有促进菌生长的作用。3个水稻品种的种子经硝酸镧处理后,对α-淀粉酶活性、呼吸速率和光合速率均有不同程度的增强效应.     

模拟酸雨下氯化镧处理对小麦发芽及幼苗生长的影响

模拟酸雨下采用不同浓度的氯化镧浸泡小麦种子,测定其对种子萌发及幼苗生长的影响。结果表明:在模拟酸雨下,1~100mg/L浓度的氯化镧可以促进小麦发芽、增加幼苗干重、促进根系生长、提高根系活力及叶绿素含量,并能抑制丙二醛和脯氨酸增多,增强了小麦对酸雨逆境的抵抗能力。从不同浓度的氯化镧对小麦的发芽、营养生长及生理指标的影响进行综合判断可知,以10mg/L的氯化镧处理效果最好。     

离体培养条件对百合鳞片辐射敏感性的影响

研究了辐射处理主因素及其与培养基成分、外植体类型的交互作用对东方百合鳞片辐射敏感性的影响。结果表明:在试验辐射剂量范围内,离体培养约6d的百合鳞片经60Coγ射线辐照后存活率随剂量增大而呈现下降趋势;辐射处理对百合鳞片的出芽率和出芽数有强烈的抑制作用。在芽诱导阶段,培养基成分在一定程度上影响鳞片的辐射敏感性;鳞片辐射敏感性随培养时间增加而减弱;外部鳞片与中部鳞片表现的辐射敏感性基本一致。     

卵泡细胞对牛卵母细胞体外成熟的影响

本研究系统探讨了卵泡细胞对牛卵母细胞体外成熟的影响。颗粒细胞及其单层细胞对卵母细胞成熟后的分裂率(分别为85.4%和89.4%,对照为88.5%)及囊胚发育率(分别为35.9%和41.2%,对照为37.1%)无明显影响(P>0.05),然颗粒细胞的条件液则使卵母细胞的分裂率(81.4%,对照为88.5%)明显降低(P<0.05)。加入5×10~6/mL 内膜细胞、内膜细胞的单层细胞或25%条件液到成熟培养系统中,卵母细胞的囊胚发育率均有所提高,分别为44.1%,42.6%及39.8%。进一步探讨应用内膜细胞条件液的几个问题发现:条件液在成熟液中的合适比例为50%,收集的适宜细胞培养阶段为3～4d;条件液制备前应加入10%的血清,不加促性腺激素。这些结果表明:内膜细胞可分泌一些有利于卵母细胞成熟的生长因子。这些生长因子分泌的质和量可能取决于内膜细胞的培养阶段、血清浓度及外源激素的种类。     

体细胞因子对牛卵母细胞体外受精的影响

本研究系统探讨了体细胞因子对牛卵母细胞体外受精的影响。在受精液中添加５％或１０％的牛卵泡液（ＢＦＦ）明显降低牛卵母细胞受精后的分裂率（３８．３％和４０．４％比对照８７．５％，Ｐ＜０．００１）和囊胚发育率（１７．４％和８．３％比对照４０．４％，Ｐ＜０．００１）。然而，在受精液中加入５０％的内膜细胞受精条件液明显提高牛卵母细胞受精后的囊胚发育率（４３．１％比３４．８％，Ｐ＜０．０５），虽然该处理对牛卵母细胞受精后的分裂率无明显影响。在体外受精系统中加入颗粒细胞的受精条件液，新鲜的输卵管细胞，输卵管细胞的单层细胞或输卵管细胞的受精条件液对牛卵母细胞的分裂率及囊胚发育率均无明显影响。相反，新鲜输卵管细胞组获得较低的分裂率（８１．７％）和囊胚发育率（３２．２％）。这些结果表明：ＢＦＦ对牛卵母细胞的体外受精具抑制作用，而内膜细胞的条件液则具促进效应。ＢＦＦ的这种受精抑制因子可能来自血清而不是卵泡细胞。     

~(60)Coγ辐射对毛竹种子活力及早期幼苗生长的影响

以毛竹(Phyllostachys edulis)干种子为材料,采用室内发芽实验、电导率测定和TTC活力测定以及早期幼苗生长分级等4种方法研究了60Coγ射线对种子活力及早期幼苗生长的诱导效应。结果表明:当辐照剂量低于100Gy时,辐照能加快种子萌发进程,提高发芽率;而当剂量超过100Gy,则对毛竹种胚组织造成损伤,抑制细胞生长和分裂,不同程度地延迟了毛竹种子发芽过程,降低了种子活力,造成早期苗高和根生长受到明显抑制,抑制作用随辐照剂量的增大而增强。毛竹种子发生诱变效应的最佳辐照剂量范围为100~175Gy。24h电导率与发芽率、发芽指数、活力指数、苗高和根生长等活力指标间存在极显著线性关系,是快速检验毛竹种子活力的重要指标。24h电导率和苗高又可作为检查辐射后毛竹种子活力变化和发生诱导效应的有效指标。     

热带地区不同土地利用系统土壤种子库的研究

本文从种类组成,种子数量,物种多样性,种子分布规律和物种相似性等方面比较了研究了海南１０种不同土地利用系统的土壤种子库特点。     

EFFECTS OF NITROGEN FORMS ON THE GROWTH AND POLYAMINE CONTENTS IN DEVELOPING SEEDS OF VEGETABLE SOYBEAN

A pot culture experiment of nitrogen forms [nitrate (NO^? ₃ ): ammonium (NH ⁺ ₄ )] with four ratios (100:0, 75:25, 50:50, and 25:75) in nutrient solutions was conducted to examine the effect of nitrogen forms on the growth and polyamine contents of developing seeds of vegetable soybean [Glycine max (L.) Merr. cv. ‘Li-xiang 95-1′]. Results showed that the best plant growth vigor was observed in (75%), and then in (50%). However, the fresh and dry weight of biomass decreased when a high concentration of either (100%) or (75%) was the primary nitrogen source in the nutrient solution. The numbers of flowers and pods in (75%) were significantly decreased compared with other ammonium-nitrate ratios in which the numbers of flowers and pods were not influenced by nitrogen forms. During the development of seeds, levels of free Put and Spd decreased, and the decrease extents were more marked in 100:0 and 25:75 (:), but the change of free Spm was opposite. Levels of conjugated and bound polyamines in all nitrogen forms increased, but the increases in 75:25 and 50:50 (:) were not so obvious as in 100:0 and 25:75 (:) treatments. The possible roles of polyamines in the adaptive mechanism of vegetable soybean seeds to different nitrogen forms were discussed.     

不同发情周期阶段和不同体积卵泡的卵母细胞对体外受精及其发育的影响

根据母牛卵巢黄体发育状态将实验用卵巢相应地划分为早期黄体(ELP)、功能黄体(LP)和退化黄体(LLP)三个试验组(实验1);实验2则按实验卵巢上卵泡的表面直径大小划分为小于2mm,2～6mm 和大于6mm 三组.采用注射器抽取法采集卵泡里的卵母细胞,然后按 Lu 等报导的方法进行体外成熟培养和体外受精。受精卵继续在体外条件下培养到囊胚阶段。实验2还进一步观察了囊胚体外发育到孵化囊胚的比率。结果表明,来自不同发情周期阶段的牛卵母细胞,经体外成熟培养后,各组体外受精分裂率(74.3%～78.4%)及体外囊胚发育率(27.7%～31.3%)均无显著差异;而来自表面直径小于2mm 卵泡的卵母细胞,其体外受精分裂率和体外囊胚发育率均显著地低于2～6mm 及大于6mm 组(P<0.01);来自直径大于6mm 卵泡的卵母细胞受精后的早期胚胎体外囊胚发育率均显著高于其余两组(p<0.01)。表明卵泡及其卵母细胞在体内的发育程度对其后体外受精及早期胚胎进一步发育的能力只有一定的影响。     

大豆豆荚光合物质转运与分配对籽粒发育的影响

运用透射电镜放射自显影技术、液体闪烁计数仪和相关生理指标测定研究了大豆生长过程中不同时期豆荚光合产物对籽粒发育的影响。结果如下:在鼓粒初期、鼓粒中期、鼓粒后期豆荚都向籽粒转运光合产物;豆荚和叶片在鼓粒中期14C-同化物的转运量达到最大;叶绿素、可溶性碳水化合物的含量也达到最高。鼓粒中期豆荚的转运量可达叶片转运量的35.6%;鼓粒后期豆荚、叶片的转运量都有所下降,但叶片下降幅度大于豆荚,此时期豆荚对籽粒的转运量达到叶片的59.6%。可见在鼓粒后期,当叶片光合功能开始衰退时,豆荚的光合产物对籽粒的贡献起到不容忽视的作用。