敦煌阳关保护区湿地植物群落优势种种间关系分析

用χ2检验和Pearson 相关系数检验以及Spearman 秩相关系数检验方法,分析了甘肃敦煌阳关保护区湿地植物群落中16 个优势种的种间关联性,从而可为其湿地的保护、管理和恢复提供科学依据。结果表明：多物种总体关联性检验结果显示16 个优势种总体种间呈负关联,表明该群落结构不稳定;χ2检验中呈正相关的物种对有53 个,呈负相关的物种对有67 个,正负关联比为0.79;Spearman 秩相关系数检验与χ2检验和Pearson 相关系数检验相比,有较高的灵敏度,其中52 个种对呈正相关,68 个种对呈负相关,正负关联比为0.76;3 种检验结果都表明,大多数种间关联程度不显著,且负关联的种对数多于正关联,说明敦煌阳关保护区湿地植物群落比较脆弱,群落的结构简单,仍处于演替之中。根据Spearman 秩相关系数结果,将16 个优势种划分为3 种类型的生态种组。种间关联性分析对全面认识阳关保护区湿地优势种间的相互关系具有重要意义,可为该保护区湿地资源的可持续利用和多样性保护提供理论依据。     

Interspecific hybridization of a multiploid mutant of durum wheat with rye and Triticum monococcum L. results in pentaploid hybrids

The multiploid mutant of durum wheat is a genotype that produces unreduced gametes. Our objective was to test the recovery of pentaploid hybrids in crosses of the mutant with rye and Triticum monococcum L. Compared with check crosses, the mutant had a two‐third reduction in percent seed set for rye crosses, but had only a slight decrease in crossability with T. monococcum. Pentaploid hybrids were associated with plump seeds of the mutant/rye cross, and with shrivelled seeds of the mutant/T. monococcum cross. We suggest that the endosperm balance number hypothesis explains the association of pentaploid hybrids with endosperm type. This association made for easy recovery of pentaploid hybrids from crosses to both species. Mature, plump seeds from the mutant/rye cross were germinated and pentaploid hybrids were recovered. One pentaploid hybrid was recovered for every 50.5 and 15.1 florets pollinated with rye and T. monococcum, respectively. Unreduced gametes in the multiploid mutant will facilitate interspecific hybridization by reducing the time to produce pentaploid plants.     

多花木兰人工生态恢复植物群落种群竞争及其生态位研究

为了掌握常吉高速公路边坡多花木兰人工生态恢复植物群落的种间竞争和生态位等生长状况,运用Hegyi的单木竞争指数模型、Shannon-Wiener公式和Shoener公式对多花木兰人工植物群落的种内与种间竞争强度、生态位宽度与生态位重叠进行研究。结果表明：多花木兰种内竞争能力与个体的地径径级成正比,多花木兰竞争能力大于刺槐、小叶女贞,原有配置的马尾松等植物已经死亡;群落各种群生态位宽度的大小顺序为：多花木兰>刺槐>小叶女贞,分别为2.271、2.147、2.088;群落各种群的生态位重叠值较大,多花木兰和刺槐的生态位重叠值最大,为0.793,多花木兰和小叶女贞生态位重叠值最小,为0.632。多花木兰能够很好地适应高速公路边坡环境,群落中已经被淘汰的其他竞争力太弱的树种不适合与多花木兰混植。     

生态位理论及其测度研究进展

许多学者都试图给生态位下定义 ,但最具代表性的当推Grinnell、Elton和Hutchinson分别给出的“空间生态位”、“功能生态位”和“多维超体积生态位”定义 ;生态位测度包括生态位宽度、生态位重叠、生态位体积及生态位维数等 ,其中生态位宽度和生态位重叠是描述一个物种的生态位以及物种生态位间关系的重要指标 .该文列举并分析了每一个测度公式的优缺点 ,进而优选出适合森林群落的生态位计测公式 .指出利用性竞争的一个必要条件是生态位重叠 ,但重叠并不一定导致竞争 ,竞争是在资源供应不足且生态位重叠条件下形成的 .     

Interspecific hybrids of Cyclamen persicum and C. graecum

Summary Interspecific crosses were made to introduce the disease resistance of Cyclamen graecum into C. persicum cultivars and the abortive hybrid embryos were rescued by ovule culture. Diploid and tetraploid cultivars of C. persicum (CPD, 2n=2x=48; CPT, 2n=4x=96) were the pistillate parents and wild form of C. graecum (CG, 2n=84) were the staminate parents. After pollination, crossed ovaries were periodically collected and examined using paraffin sections. Histological observations suggested that both hybrid ovules of CPD × CG and CPT × CG should be transferred to the culture medium 35 days after pollination. Based upon this observation, crossed ovaries were collected 35 days after pollination, then ovules with placenta were explanted on culture medium and cultured in the dark at 25°C. Plantlets were induced from ovules cultured in MS medium containing 3% sucrose and 10% coconut milk. The hybrids (2n=66) derived from CPD × CG failed to yield viable seeds by self-pollination, although they showed some pollen fertility. In contrast, the hybrids (2n=90) derived from CPT × CG showed high pollen fertility and yielded viable seeds by self-pollination. Furthermore, they were resistant to disease caused by Fusarium oxysporum f. sp. cyclaminis, Erwinia herbicola pv. cyclamenae and Pseudomonas marginalis pv. marginalis.Abbreviations CPD C. persicum diploid - CPT C. persicum tetraploid - CG C. graecum     

Comparing mating designs to restore seed production of interspecific hybrids between Trifolium repens (white clover) and Trifolium uniflorum

Interspecific hybrids between Trifolium uniflorum and cultivated white clover (Trifolium repens) have highly useful characteristics for temperate pastoral systems derived from both parent species. However, the early hybrids (F₁ and BC₁) also have unacceptably poor seed production for commerce. This study analysed the basis for the poor seed production and investigated breeding strategies for overcoming the problem. The BC₁F₁ generation produced lower‐than‐expected numbers of heads per plant and seeds per floret. Backcrossing of selected hybrids to white clover corrected these deficiencies and created new variation. Seed numbers were also returned to near target levels by recurrent selection within the BC₁ generation. Thus, it was possible to retain a theoretical average of 25% of T. uniflorum genome and still achieve high seed production per plant. The BC₁F₂ and BC₂F₁ generations produced high seed numbers per plant, along with reasonable variation. Both of these second‐generation hybrid forms have high reproductive potential and should be the focus for the selection of the desired combinations of agronomic and seed production traits.     

豇豆属食用豆类间的远缘杂交

【目的】明确豇豆属下不同食用豆种间的杂交亲和性,为开展豇豆属食用豆远缘杂交育种提供参考。【方法】以绿豆、小豆、黑吉豆、饭豆、豇豆5种主要的豇豆属食用豆栽培豆种和Vigna minima、Vigna nakashimae、Vigna riukiuensis 3种小豆、饭豆的近缘野生种为亲本,进行豇豆属下食用豆种间的远缘杂交,并对“绿豆×小豆”、“饭豆×小豆”、“小豆×饭豆”的杂种幼胚进行幼胚拯救。通过调查杂交成荚率和杂种F₁的农艺性状表现,分析豇豆属下不同食用豆杂交组合间的杂交亲和性。【结果】各食用豆种间亲缘关系的远近及母本的选择影响远缘杂交结果。除包含豇豆种的杂交组合外,其他食用豆种间正反交杂交组合均能够结荚,杂交荚和杂交籽粒的发育程度在各组合间存在差异。“绿豆×黑吉豆”、“小豆×Vigna minima”、“小豆×Vigna nakashimae”、“小豆×Vigna riukiuensis”4个杂交组合不存在受精前的遗传障碍,杂交成荚率较高,幼胚发育阶段存在不同程度的发育障碍,但均可以获得能够正常出苗的杂交籽粒,F₁ 植株结实率降低。绿豆和饭豆间正反交均能够结荚,但绿豆作母本时的成荚率显著高于饭豆作母本时的成荚率,且能够收获成熟的杂交荚和杂交籽粒。F₁植株高度不育,即使与绿豆或饭豆回交也均不能获得有活力的后代种子。“绿豆×小豆”、“饭豆×小豆”2个杂交组合不存在受精前的杂交障碍,然而在受精后幼胚生长阶段却存在发育障碍。通过幼胚拯救可以获得两者的后代植株,前者F₁高度不育,后者F₁可育,但结实率降低。其他杂交组合间存在杂交荚发育一段时间后干枯或掉落、杂交籽粒胚败育等现象,未能获得后代植株。【结论】绿豆作母本与黑吉豆、小豆、饭豆杂交更利于杂交荚和杂交籽粒的发育;黑吉豆与小豆、饭豆杂交时存在胚败育现象;饭豆作母本与小豆杂交经幼胚拯救可以获得可育的F₁植株;小豆与近缘野生种的杂交亲和性优于饭豆;豇豆与其他食用豆类间杂交均未成功。     

Changes in the herbicide sensitivity and competitive ability of Abutilon theophrasti over 28 years: Implications for hormesis and weed evolution

BACKGROUND

The potential of weed species to respond to selection forces affecting the evolution of weedy traits such as competitive ability is poorly understood. This research characterized evolutionary growth changes in a single Abutilon theophrasti Medik. population comparing multiple generations collected from 1988 to 2016. A competition study was performed to understand changes in competitive ability, and a herbicide dose–response study was carried out to assess changes in sensitivity to acetolactate synthase-inhibiting herbicides and glyphosate over time.

RESULTS

When grown in monoculture, A. theophrasti biomass production per plant increased steadily across year-lines while leaf number decreased. In replacement experiments, A. theophrasti plants from newer year-lines were more competitive and produced more biomass and leaf area than the oldest year-line. No clear differences in sensitivity to imazamox were observed among year-lines. However, starting in 1995, this A. theophrasti population exhibited a progressive increase in growth in response to a sublethal dose of glyphosate (52 g a.e. ha⁻¹), with the 2009 and 2016 year-lines having more than 50% higher biomass than the nontreated control.

CONCLUSION

This study demonstrates that weeds can rapidly evolve increased competitive ability. Furthermore, the results indicate the possibility of changes in glyphosate hormesis over time. These results highlight the importance of the role that rapid (i.e., subdecadal) evolution of growth traits might have on the sustainability of weed management strategies. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

人工合成甘蓝型油菜高频率再生研究初报

资源材料保存在作物遗传资源的研究与利用中起到非常重要的作用。该实验以不同来源的人工合成甘蓝型油菜KH106，KH109，KH111D为材料，以花序轴，子房，果柄为外植体研究其再生情况，结果表明，由芥蓝和小白菜人工合成的甘蓝型油菜KH106的再生频率极显著高于由羽衣甘蓝和白菜型油菜人工合成的甘蓝型油菜KH109和KH111；与花序轴和子房为外植体再生频率相比，以果柄为外植体平均再生频率最高，差异达到极显著水平；利用不同预处理培养基处理不同时间，结果显示不经过预处理直接接种到分化培养基上再生频率最高。     

Past, present and future criteria to breed crops for water-limited environments in West Africa

Asia's Green Revolution of the 1960s and 1970s has largely bypassed West Africa, and “modern” (high-yielding, input responsive) germplasm for staple crops has found comparatively little adoption, except for systems that are have good access to markets and sufficient water resources. It is unlikely, however, that breeding objectives conserving traditional crop characteristics as found in extensive systems would have been more successful. The authors identify systems caught in the agricultural transition from subsistence to intensified, market-oriented production as the most important target for crop improvement, and provide examples of new breeding objectives for cowpea, sorghum and upland rice. In each of these cases, breeders, with the help of physiologists, have developed innovative plant-type concepts that combine improved yield potential and input responsiveness with specific traditional crop characteristics that remain essential during the agricultural transition. In the case of cowpea, dual-purpose varieties were developed that produce a good grain yield due to an erect plant habit, then produce new leaves enabling a second harvest of green foliage. For upland rice systems that are limited by labour (mainly needed to control weeds that abound due to shortened fallow periods), a weed competitive plant type was developed from Oryza sativa × Oryza glaberrima crosses. Lastly, sorghum breeders who had previously deselected photoperiod sensitivity are now re-inserting sensitivity into plants having “modern” architecture, in order to allow for flexible sowing dates while maintaining an agro-ecologically optimal time of flowering near the end of the wet season. The ecophysiological basis of these plant types, their place in current and future cropping systems, as well as the problem of under-funding for their realisation, are discussed.