甜瓜属植物种间杂交研究进展

在甜瓜属野生种Cucumis hystrix Chakr.和栽培黄瓜之间的种间杂交取得成功的基础上,简要回顾了甜瓜属植物种质资源和系统学的研究情况,然后从甜瓜属植物种间杂交的概况、种间杂交的障碍及其解决途径等三个方面,回顾和讨论了甜瓜属植物的种间杂交的研究进展,并对进一步通过种间杂交研究利用甜瓜属野生植物资源的前景进行了展望.     

甜瓜属植物种间杂交研究进展

在甜瓜属野生种Cucumis hystrix Chakr. 和栽培黄瓜之间的种间杂交取得成功的基础上,简要回顾了甜瓜属植物种质资源和系统学的研究情况,然后从甜瓜属植物种间杂交的概况、种间杂交的障碍及其解决途径等三个方面,回顾和讨论了甜瓜属植物的种间杂交的研究进展,并对进一步通过种间杂交研究利用甜瓜属野生植物资源的前景进行了展望。     

甜瓜属种间杂交线粒体DNA的遗传分析

为了研究甜瓜属种间杂交线粒体DNA的遗传规律,对甜瓜属人工杂交合成的异源四倍体新种(Cucumis hytivus Chen and Kirkbride.)的S5后代及其杂交母本甜瓜属野生种（Cucumis hystrix Chakr.）和父本栽培种黄瓜‘北京截头’(Cucumis sativus L.)线粒体中apocytochrome b (cob), NADH dehydrogenase subunit 1 (nad 1), NADH dehydrogenase subunit 7(nad 7) 基因序列片断进行了测序与分析。结果显示3个种长度为909 bp cob, 943 bp nad 1和880 bp nad 7基因片断序列中分别存在着相应的1、7和17个多态性核苷酸位点,其中新种与父本‘北京截头’相同而与母本野生种不同的多态性碱基位点分别有1、6和14个,nad 1和nad 7中分别只有1和3个多态性位点与双亲都不相同。该结果表明甜瓜属hystrix譻ativus种间杂交后代线粒体DNA多态性碱基位点主要来源于父本而不是母本,线粒体DNA主要表现为父系遗传。     

新疆甘草属的种间杂交

试验以居群为单位的新疆甘草属７个种进行种间人工杂交。通过对种间杂交结实量（ＲＳ）和亲本种平均结实量（ＲＳｍ和ＲＳｆ）的分析比较,测出相应的杂交结实指数（ＩＳ）、初步了解种间杂交亲和性的大小,为甘草属植物系统与演化的研究提供参考依据。     

姜花属种间杂交胚拯救研究

为提高姜花属种间杂交胚挽救中幼胚萌发率,以白姜花×金姜花的胚珠为试材,研究不同胚珠发育时期、不同培养基及低温处理果实对幼胚萌发率的影响.结果表明,白姜花×金姜花胚挽救的适宜培养基是MS+0.1 mg/L BA十0.1 mg/L NAA;接种时期以60 d的幼胚培养效果最佳;低温处理果实3～6 d能有效提高幼胚的萌发率.     

棉属种间杂交胚珠的离体培养

棉属(Gossypium)的种间杂交是育种的重要手段之一。通过种间杂交,可将棉属中某些种,尤其是野生种和半野生种的优良特性引入生产上栽培的种,从而创造人们所需要的品质好、抗逆性强的新类型或新品型。这是长期以来育种工作者的愿望。同时,棉属的种间杂交对创造雄性不育系,探索棉属的分类与进化以及对于遗传育种理论的研究都有重要意义。然而,棉属的种间杂交也和其它一些植物一样存在着杂交亲本的不亲和性和杂种后代的不育性。根据胚胎学     

棉属栽培种与野生种杂交的不亲和性

本文研究了棉属栽培种与野生种杂交的不亲和性,试验材料涉及5个染色体组,包括2个栽培种(陆地棉和中棉)和5个野生种(戴维逊氏棉、瑟伯氏棉、三裂棉、阿拉伯棉和比克氏棉)。以陆地棉作母本,异己花粉管在花柱中生长缓慢,有花粉管胚珠低于10%,陆地棉×戴维逊氏棉杂种胚在子叶期坏死。以中棉作母本,不亲和性主要表现在受精后的胚胎发育过程中。     

Cucumis属3种不同倍性种间杂交后代的同工酶分析

以3种不同倍性的Cucum is属种间杂交后代[异源四倍体C.hy tivus(2n=4x=38,HHCC)、异源三倍体(2n=3x=26,HCC)和正反交种间杂种F1(2n=2x=19,HC/CH)]及其双亲为试材,比较研究了过氧化物酶(POD)和酯酶(EST)同工酶在不同器官中的酶谱表达特性.结果表明,花蕾中的POD和EST同工酶谱带都比叶片中的丰富,表现出明显的组织特异性.在相同器官的同一酶系统中,3种不同倍性种间杂交后代的酶谱基本一致,主要表现为互补双亲的酶带,同时出现了双亲所没有的酶带(POD4c和EST3b等),表明远缘杂交扩大了黄瓜的遗传基础.此外,在幼叶和花蕾的POD同工酶中,大部分酶带活性随染色体倍性增加而减弱,表明基因剂量与POD同工酶酶谱的表达呈负相关.     

几种同域分布姜花属植物的种间杂交亲和性

种间配子不亲和以及种间杂交种子活力低是众多的物种间杂交隔离机制中的两个方面。通过对云南澜沧地区分布的4种（型）姜花属植物——圆瓣姜花（Hedychium forrestii）、草果药(Hspicatum)、两类型滇姜花（Hyunnanense）间进行野外杂交试验,比较杂交结实率、每果种子数以及杂交种子的萌发参数等指标来分析4种（型）姜花之间的杂交亲和性和杂交后代表现,发现4种（型）姜花属植物配子间都具有不同程度的亲和性,但种间杂交种子的萌发适合度比同种授粉获得的种子低。结果表明,这4种（型）姜花属植物间配子亲和性不是有效的种间隔离机制,种间杂交种子活力低是一种不完全的隔离机制,它们在同域分布的地区,仍然有形成杂交后代的可能性。     

不同光照条件下3种冬青属植物的光合特征日变化研究

以冬青、绿冬青、全缘枸骨为材料,运用光生理生态研究方法,对不同遮荫条件下,3种冬青属植物的光生理变化进行了研究。结果表明：3种冬青在全光照下的净光合速率高于透光率45％下的,透光率45％的高于透光率20％的,且全光照处理的净光合速率日变化均为双峰曲线,反映3种冬青均为中性树种。但从午休程度和午休后光合恢复情况来看,全缘枸骨对强光的适应能力好于绿冬青,绿冬青好于冬青。叶片光合色素和比叶重变化进一步证明,全缘枸骨适应能力最好,绿冬青次之,冬青相对较差。该研究对揭示各树种光适应特性和合理的园林配置有指导意义。     

Adaptation of the Photosynthetic Apparatus of Scenedesmus obliquus to Strong and Weak Light Conditions

Homocontinuous cultures of the unicellular green alga Scenedesmus obliquus were grown under strong (28 W/m²～28,000 lux) and weak (5 W/m²～5000 lux) light conditions to simulate the conditions of ‘sun’ and ‘shade’ plants. As in higher plants the cells adapted to strong light had less chlorophyll but demonstrated a higher photosynthetic capacity and a higher respiration rate, so that their compensation point was reached at three times higher energy than in the cells grown under low light intensities. The CO₂ fixation rate and the RuDP carboxylase activity under saturating light intensities were both higher in the cells grown in strong light. In spite of the differences in the pigment content and in the light saturated photosynthetic capacities for both cultures, the quantum yields of photosynthetic oxygen evolution were equal. As documented for some species of higher plants Scenedesmus is not genetically determined to be either a ‘sun’ or ‘shade’ organism but can adapt its photosynthetic apparatus to the different light intensities.     

烯效唑浸种对玉米苗期某些光合特性的影响

经烯效唑浸种后的玉米苗期叶片变厚,比叶重增加,叶片叶绿素含量和叶绿素a/b比值增加,PEP羧化酶活性增强,净光合速率提高;以40mg·kg-1烯效唑浸种的效果最好.     

Transfer of C(4) Photosynthetic Characters through Hybridization of Flaveria Species

Transfer of C₄ photosynthetic traits was studied through hybridization of Flaveria trinervia (Spreng.) Mohr (C₄) and Flaveria brownii A.M. Powell (C₄-like) with Flaveria linearis Lag. (C₃-C₄) and the C₃ species Flaveria pringlei Gandoger (C₃). Fertility was low, based on irregular chromosome pairing and low pollen stainability, except in F. brownii × F. linearis which had bivalent pairing and 76% stainable pollen. Hybrids had apparent photosynthesis values of 71 to 148% of the midparental means, while the CO₂ compensation concentration was similar to the C₄ or C₄-like parent, except in hybrids having the C₃ species F. pringlei as a parent. Inhibition of apparent photosynthesis by O₂, and phosphoenolpyruvate carboxylase and NADP-malic enzyme activities and subunit levels in the hybrids were closer to the C₃ or C₃-C₄ parent. The species F. brownii and F. trinervia were equal in their capacity to transfer reduced O₂ inhibition of AP and CO₂ compensation concentration values to hybrids with F. linearis (C₃-C₄), although hybrids with F. trinervia had higher PEPC activity. The O₂ inhibition of AP was correlated with the logarithm of activities of phosphoenolpyruvate carboxylase (r = −0.95) and NADP-malic enzyme (r = −0.87). These results confirm that C₄ traits can be transferred by hybridization of C₃-C₄ and C₄ or C₄-like species, with a higher degree of C₄ photosynthesis than exists in C₃-C₄ species, and at least in F. brownii × F. linearis, fertile progeny are obtained.     

不同生长光强下8种红树植物幼苗叶片的光响应特征

为探讨红树植物光适应的生理生态策略,对6种真红树植物[无瓣海桑(Sonneratia apetala)、秋茄(Kandelia candel)、木榄(Bruguiera gymnorrhiza)、桐花树(Aegiceras corniculatum)、老鼠簕(Acanthus ilicifolius)、卤蕨(Acrostichum aureum)]和2种半红树植物[银叶树(Heritiera littoralis)、黄槿(Hibiscus tiliaceus)]的1 a生幼苗在不同生长光强(自然光强的100%、45%、30%、10%)下的光合光响应特征进行了研究。结果表明,不同生长光强对红树植物光响应特征的影响因物种而异,遮荫显著提高了秋茄和木榄的最大净光合速率(Pmax),而对其他红树植物的Pmax没有显著影响;秋茄在45%光强下具有较高的Pmax,木榄的Pmax则在45%和30%光强下显著高于其他2个处理。随着生长光强的下降,秋茄幼苗叶片的光饱和点显著上升,木榄、老鼠簕和卤蕨的光补偿点呈下降趋势,木榄和卤蕨的表观量子效率升高的同时暗呼吸速率下降。木榄、老鼠簕和卤蕨具有较强的耐荫性,...     

Cooperation of Photosynthetic Reaction Center of Photosystem II under Weak Light as Shown by Light Intensity-dependence of the Half-effective Dose of Atrazine

The binding constant (K) and number of binding sites (N) of atrazine to isolated photosystem (PS) II membranes were measured with an apparent correlation between N and the activity of oxygen evolution. Upon the addition of an electron acceptor, N became equal to the total number of the population of PS II reaction centers irrespective of having oxygen-evolving activity, about 4 mmol per mole of chlorophyll, with a concomitant decline of K from 1.32 (±0.34) × 10⁷ M^–1 to 4.09 (±0.40) × 10⁶ M^–1 . NH₂OH and NaCl treatments, which inactivate oxygen evolution, affected neither the binding to PS II membranes of the extrinsic 33-kDa protein or of atrazine. The atrazine binding sites that are latent in CaCl₂-treated PS II membranes was partially restored by the reconstitution of the membranes with isolated extrinsic 33-kDa protein. An oxidizing system involving the 33-kDa protein may provide a suitable structure of PS II reaction center complex for atrazine binding. The level of inhibition of oxygen-evolving activity by atrazine under the saturating intensity of light parallels the fraction of the photosystem (PS) II reaction center with the quinone-binding site blocked by atrazine. In contrast, under a rate-limiting intensity of light, percents of remaining oxygen-evolving activity after the addition of atrazine correlated with the 1.33th power of the fraction of atrazine-free binding sites. Inhibition of PS II complexes more than one that bound with atrazine suggests a cooperation between PS II complexes to evolve oxygen under weak light intensity.     

Comparison of Some Photosynthetic Characters Between Two Hybrid Rice Combinations Differing in Yield Potential

Photosynthetic characteristics of two hybrid rice combinations, Peiai 64S/E32 and Shanyou 63, were compared at the panicle differentiation stage. As compared with Shanyou 63, the new combination Peiai 64S/E32 showed a significantly higher net photosynthetic rate (P _N), apparent quantum yield of carbon assimilation (_c), carboxylation efficiency (CE), and photorespiratory rate (R _P) as well as leaf chlorophyll content, but a significantly lower dark respiration rate (R _D) and compensation irradiance (I _c). It also showed a slightly higher photochemical efficiency (F_v/F_m and F/F_m) of photosystem 2, a lower non-photochemical quenching (q_N), and a similar CO₂ compensation concentration () as compared to Shanyou 63.     

Sugar and Light Effects on the Condition of the Photosynthetic Apparatus of Arabidopsis thaliana Cultured in vitro

Light and sugars are fundamental elements of plant metabolism and play signaling roles in many processes. They are also critical factors determining the condition of plants cultured in vitro. The aim of this work was to investigate the simultaneous influence of irradiance and sugar content in the medium on the growth and photosynthetic apparatus condition of Arabidopsis thaliana in vitro. Plants were grown on media containing 1 or 3% of sucrose or glucose at three irradiances: 25, 100, and 250 μmol m⁻² s⁻¹ (weak, medium, and strong light). Media without sugar were used for control plants. Plant growth parameters were measured and the following physiological processes were investigated: photosynthesis, blue light-induced chloroplast relocations, and xanthophyll cycle activity. The expression of genes related to these processes was analyzed. The presence of sugar in the medium was found to be essential for the growth of Arabidopsis in vitro. Weak light significantly limited growth and the capacity to acclimate to changing light conditions. Strong light was a source of stress in some cases. Contrary to earlier reports, exogenous sugars showed a positive effect on photosynthesis. At higher concentration they acted as photoprotectants, overcoming the negative influence of strong light on photosynthesis and the xanthophyll cycle. The expression of all investigated genes was influenced by irradiance and sugar presence. In many cases differential effects of sugar type and concentration could be observed. The specific effects of some irradiance/sugar concentration combinations point to possible interactions between sugar- and light-induced signaling pathways.     

低温弱光对辣椒幼苗光合特性与光合作用启动时间的影响

以辣椒(Capsicum annuumL.)幼苗为试材,研究了偏低温弱光(19℃/12℃昼/夜,90μmol?m-2?s-1)和临界低温弱光(15℃/8℃昼/夜,90μmol?m-2?s-1)胁迫10 d后的光合特性与光合作用启动时间的变化.结果表明:无论是在偏低温弱光还是在临界低温弱光下,辣椒幼苗的光补偿点(LCP)、光饱和点(LSP)、光饱和时的光合速率(Amax)和表观量子产额(AOY)下降;CO2补偿点(CCP)升高,而CO2饱和点(CSP)、CO2饱和时的光合速率(Amax)以及羧化效率(CE)下降;温度补偿点(TCP)降低;光合作用启动时间(STP)延长.在偏低温弱光下,辣椒幼苗有着更高的光与CO2利用能力和利用效率,光合作用启动时间较短,但温度补偿点较高.