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61.
Closely related species often differ in traits that influence reproductive success, suggesting that divergent selection on such traits contribute to the maintenance of species boundaries. Gymnadenia conopsea ss. and Gymnadenia densiflora are two closely related, perennial orchid species that differ in (a) floral traits important for pollination, including flowering phenology, floral display, and spur length, and (b) dominant pollinators. If plant–pollinator interactions contribute to the maintenance of trait differences between these two taxa, we expect current divergent selection on flowering phenology and floral morphology between the two species. We quantified phenotypic selection via female fitness in one year on flowering start, three floral display traits (plant height, number of flowers, and corolla size) and spur length, in six populations of G. conopsea s.s. and in four populations of G. densiflora. There was indication of divergent selection on flowering start in the expected direction, with selection for earlier flowering in two populations of the early‐flowering G. conopsea s.s. and for later flowering in one population of the late‐flowering G. densiflora. No divergent selection on floral morphology was detected, and there was no significant stabilizing selection on any trait in the two species. The results suggest ongoing adaptive differentiation of flowering phenology, strengthening this premating reproductive barrier between the two species. Synthesis: This study is among the first to test whether divergent selection on floral traits contribute to the maintenance of species differences between closely related plants. Phenological isolation confers a substantial potential for reproductive isolation, and divergent selection on flowering time can thus greatly influence reproductive isolation and adaptive differentiation. 相似文献
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Coral Reefs - Pacific crown-of-thorns starfish (Acanthaster cf. solaris) are known to be widely distributed, and previous studies (showing limited genetic structure) suggest that there are high... 相似文献
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Matić Ivana Z. Ergün Sercan Đorđić Crnogorac Marija Misir Sema Aliyazicioğlu Yüksel Damjanović Ana Džudžević-Čančar Hurija Stanojković Tatjana Konanç Kalbiye Petrović Nina 《Cytotechnology》2021,73(3):373-389
Cytotechnology - Six extracts were obtained from plant species Hypericum perforatum L., collected at Samsun in Turkey. The aim of this study was to examine the mechanisms of the anticancer activity... 相似文献
64.
Tolar Tjaša Galik Alfred Le Bailly Matthieu Dufour Benjamin Caf Nina Toškan Borut Bužan Elena Zver Lars Janžekovič Franc Velušček Anton 《Vegetation History and Archaeobotany》2021,30(1):107-118
Vegetation History and Archaeobotany - Multi-proxy analysis of the coprolites which were found during excavations at two Late Neolithic (fourth millennium bc) pile-dwelling sites (Črnelnik and... 相似文献
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Anja Rödiger Birgit Agne Dirk Dobritzsch Stefan Helm Fränze Müller Nina Pötzsch Sacha Baginsky 《The Plant journal : for cell and molecular biology》2021,105(5):1431-1442
We report here a detailed analysis of the proteome adjustments that accompany chromoplast differentiation from chloroplasts during bell pepper (Capsicum annuum) fruit ripening. While the two photosystems are disassembled and their constituents degraded, the cytochrome b6f complex, the ATPase complex, and Calvin cycle enzymes are maintained at high levels up to fully mature chromoplasts. This is also true for ferredoxin (Fd) and Fd-dependent NADP reductase, suggesting that ferredoxin retains a central role in the chromoplasts’ redox metabolism. There is a significant increase in the amount of enzymes of the typical metabolism of heterotrophic plastids, such as the oxidative pentose phosphate pathway (OPPP) and amino acid and fatty acid biosynthesis. Enzymes of chlorophyll catabolism and carotenoid biosynthesis increase in abundance, supporting the pigment reorganization that goes together with chromoplast differentiation. The majority of plastid encoded proteins decline but constituents of the plastid ribosome and AccD increase in abundance. Furthermore, the amount of plastid terminal oxidase (PTOX) remains unchanged despite a significant increase in phytoene desaturase (PDS) levels, suggesting that the electrons from phytoene desaturation are consumed by another oxidase. This may be a particularity of non-climacteric fruits such as bell pepper that lack a respiratory burst at the onset of fruit ripening. 相似文献
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Nina G. Jablonski 《American journal of physical anthropology》2021,175(2):437-447
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Ying Liu Christoph Bachofen Yanjing Lou Zhi Ding Ming Jiang Xianguo Lü Nina Buchmann 《Journal of Plant Ecology》2021,14(2):337
温度变化和钾添加对扁秆藨草生长及繁殖的影响
人类活动导致的气候变暖和农业面源污染已被认为是影响湿地植物生长和繁殖的重要因素。为了预 测和缓解这些人类活动的影响,研究沼泽植物如何响应这些环境变化具有重要意义。本研究选取在欧亚 大陆广泛分布的莎草科球茎植物扁秆藨草(Bolboschoenus planiculmis)为研究对象,考察气温变化(恒温: 15、20、25 °C及交替温度:20/10和30/15 °C)和钾添加(0、1、3、9 和18 mmol/L)对其生长和繁殖性状 的影响。研究结果表明,高的恒温(20、25 °C)比高的交替温度(30/15 °C)更有利于扁秆藨草球茎的形成, 而地上生物量和株高一般在较高温度下(30/15、25 °C)达到最大值。扁秆藨草的繁殖和生长性状均与施钾量 呈驼峰型关系,最适施钾量在1–3 mmol/L K。高恒温效应和最适钾浓度的交互作用对繁殖性状的促进作 用最大,但是,较高的温度(30/15和25 °C)和0–9 mmol/L的钾浓度只促进了生长性状的生长。综上所述, 扁秆藨草的种群优势度可能受益于全球变暖和额外的钾添加。 相似文献