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71.
72.
Luana Beatriz dos Santos Nascimento Massimiliano Tattini 《International journal of molecular sciences》2022,23(9)
Plants evolved an impressive arsenal of multifunctional specialized metabolites to cope with the novel environmental pressures imposed by the terrestrial habitat when moving from water. Here we examine the multifarious roles of flavonoids in plant terrestrialization. We reason on the environmental drivers, other than the increase in UV-B radiation, that were mostly responsible for the rise of flavonoid metabolism and how flavonoids helped plants in land conquest. We are reasonably based on a nutrient-deficiency hypothesis for the replacement of mycosporine-like amino acids, typical of streptophytic algae, with the flavonoid metabolism during the water-to-land transition. We suggest that flavonoids modulated auxin transport and signaling and promoted the symbiosis between plants and fungi (e.g., arbuscular mycorrhizal, AM), a central event for the conquest of land by plants. AM improved the ability of early plants to take up nutrients and water from highly impoverished soils. We offer evidence that flavonoids equipped early land plants with highly versatile “defense compounds”, essential for the new set of abiotic and biotic stressors imposed by the terrestrial environment. We conclude that flavonoids have been multifunctional since the appearance of plants on land, not only acting as UV filters but especially improving both nutrient acquisition and biotic stress defense. 相似文献
73.
华沙大学新图书馆——树林中的城市 总被引:2,自引:0,他引:2
华沙大学新图书馆根据两位波兰建筑师Marek Budzyski和Zbigniew Badowski在竞赛中获一等奖的方案实施,建筑师的设计主题是“树林中的城市”。整体建筑素雅,环境优美,其屋顶花园为欧洲最大和最漂亮的屋顶花园之一。本文简要介绍和分析了了华沙大学新图书馆及其花园的概况与设计理念。 相似文献
74.
75.
沈阳奥林匹克中心体育场设计以"月桂树之冠"为寓意主题,充分体现"绿色、科技、人文"奥运的宗旨,意在创造一座与环境共生的生态型体育场。 相似文献
76.
目的为了缓解中国人口老龄化与社会物质资源配置之间的矛盾,将共生理论与服务设计理念运用到社区老龄娱教服务体系中,为老龄用户提供多元化的娱教服务。方法运用共生理论对参与社区娱教服务的共生单元、共生模式、共生环境进行具体分析,再融合服务设计理念,探讨服务供给主体之间的共生关系,优化系统中的资源配置,实现主体间的协同合作,完成供需平衡的服务体验链的建构,并延展出社区老龄娱教服务系统设计策略。结论通过多元共生模式的社区娱教服务设计理论的架构,明确设计方向,并建立系统功能结构模块,形成多元服务主体共生联动的娱教服务系统,提升社区娱教服务的参与性与结果的适用性,为以后的老龄服务事业提供新的机遇和可借鉴的理论依据。 相似文献
77.
钱颖 《宁波工程学院学报》2007,19(1):126-129
高校学生受到家庭文化背景、先前知识、志向水平、智力、能力倾向、学习方式和性别等因素影响,存在着明显的个性差异。为使每一个学生都得到充分的发展,教师在教育教学中要承认差异,认清差异,有针对地实行差异教学。网络技术的应运而生,给教育带来的生机。如何在教学中运用网络技术,实施有差异的教学,促进有差异的发展,本文根据自己的实践经验,进行了一些探讨。 相似文献
78.
针对时分双工/码分多址(TDD/CDMA)系统在动态调整上下行时隙的分配时会产生严重的交叉时隙干扰问题,提出了一种基于隔离区域的移动台间干扰的解决方案。隔离区域由移动台接收到的导频信号差值确定,该隔离区域范围较小,从而交叉时隙容量较大。同时分析了交叉时隙基站间干扰,结果表明,由于基站间传输条件较好,不能完全克服基站间干扰。因此TDD/CDMA系统(如时分同步CDMA(TD-SCDMA))的动态调整上下行切换点技术仍然很难应用于实际系统中。 相似文献
79.
Chaima Chammakhi Alexandre Boscari Marie Pacoud Grgoire Aubert Haythem Mhadhbi Renaud Brouquisse 《International journal of molecular sciences》2022,23(21)
Drought is an environmental stress that strongly impacts plants. It affects all stages of growth and induces profound disturbances that influence all cellular functions. Legumes can establish a symbiosis with Rhizobium-type bacteria, whose function is to fix atmospheric nitrogen in organs called nodules and to meet plant nitrogen needs. Symbiotic nitrogen fixation (SNF) is particularly sensitive to drought. We raised the hypothesis that, in drought-stressed nodules, SNF inhibition is partly correlated to hypoxia resulting from nodule structure compaction and an increased O2 diffusion barrier, and that the nodule energy regeneration involves phytoglobin–nitric oxide (Pgb–NO) respiration. To test this hypothesis, we subjected faba bean (Vicia faba L.) plants nodulated with a Rhizobium laguerreae strain to either drought or osmotic stress. We monitored the N2-fixation activity, the energy state (ATP/ADP ratio), the expression of hypoxia marker genes (alcohol dehydrogenase and alanine aminotransferase), and the functioning of the Pgb–NO respiration in the nodules. The collected data confirmed our hypothesis and showed that (1) drought-stressed nodules were subject to more intense hypoxia than control nodules and (2) NO production increased and contributed via Pgb–NO respiration to the maintenance of the energy state of drought-stressed nodules. 相似文献
80.
Karine Loth Nicolas Parisot Franoise Paquet Hugo Terrasson Catherine Sivignon Isabelle Rahioui Mlanie Ribeiro Lopes Karen Gaget Gabrielle Duport Agns F. Delmas Vincent Aucagne Abdelaziz Heddi Federica Calevro Pedro da Silva 《International journal of molecular sciences》2022,23(20)
Aphids (Hemiptera: Aphidoidea) are among the most detrimental insects for agricultural plants, and their management is a great challenge in agronomical research. A new class of proteins, called Bacteriocyte-specific Cysteine-Rich (BCR) peptides, provides an alternative to chemical insecticides for pest control. BCRs were initially identified in the pea aphid Acyrthosiphon pisum. They are small disulfide bond-rich proteins expressed exclusively in aphid bacteriocytes, the insect cells that host intracellular symbiotic bacteria. Here, we show that one of the A. pisum BCRs, BCR4, displays prominent insecticidal activity against the pea aphid, impairing insect survival and nymphal growth, providing evidence for its potential use as a new biopesticide. Our comparative genomics and phylogenetic analyses indicate that BCRs are restricted to the aphid lineage. The 3D structure of BCR4 reveals that this peptide belongs to an as-yet-unknown structural class of peptides and defines a new superfamily of defensins. 相似文献