共生真菌对植物抗旱性的影响及机制研究进展

共生真菌分布广泛,与植物形成共生体。研究表明,某些共生真菌可以增强植物对生物胁迫和非生物胁迫,包括干旱、高温、矿物质失调和高盐的耐受性,从而使被内生真菌感染的植株比未感染植株对有限的资源更具竞争力而且生长得更好。植物共生真菌可以通过多样化途径来增强植物体的抗性机能,其提高抗旱性的机制主要表现在营养物质的吸收、植物的保护系统、激素调节、水解酶、水分代谢、相关基因表达、植物防御信号途径等方面。总结共生真菌提高植物耐旱性的机制研究进展,以使读者能全面、及时地了解这一领域的研究动态。     

气象学视域下的南宋《局方》续添方剂考述

[目的]探讨气象学视域下南宋两次《太平惠民和剂局方》(以下简称《局方》)续添与气候变化的联动关系。[方法]通过数据分析,找出南宋续添方剂与《局方》的整体差异;通过史料考证,归纳两宋尤其是南宋气候变动的特点;基于以上文献及数据,探讨南宋《局方》续添方剂与气候变动的相关性。[结果]绍兴续添方、续添诸局经验秘方体现出与《局方》整体的显著差异,也表现出与气候变动的显著相关性。在时间上,两次续添分别发生在两次重大气候变动的中后期。在方剂选择上,绍兴续添方体现为对寒湿气候的响应,以寒湿为病因、病机、主治的续添方剂最为突出,续添诸局经验秘方体现为对大量自然灾害及沙尘气候的响应,以虚证为病因、病机、主治的续添方剂最为典型。[结论]绍兴续添方和续添诸局经验秘方均受到气候变动的显著影响。从气候变化的角度阐述《局方》续添方剂的特点,丰富了医学史理论。     

黄芪miRNA的预测及其干旱表达模式分析

目的利用生物信息学手段预测黄芪Astragalus membranaceus的miRNA及其靶基因,应用定量PCR分析其干旱胁迫表达模式,为黄芪miRNA研究奠定基础。方法下载公共核酸数据库中的黄芪高通量测序序列,使用Trinity软件拼接获得转录本数据。利用生物信息学预测方法进行黄芪miRNA及其靶基因的预测,并对靶基因进行功能分类分析。利用茎环引物荧光定量PCR方法验证miRNA的存在,并分析miRNA在干旱胁迫下的表达模式。结果序列拼接获得88 263条黄芪转录组数据。使用这些数据预测到分属于17个家族的17个miRNA序列以及相应的茎环结构前体。这些miRNA靶向的145个基因主要参与基因转录调控、物质代谢、信号转导、胁迫应答和蛋白翻译后修饰等生物学过程。随机选取8个miRNA进行茎环引物荧光定量PCR验证,其干旱逆境表达模式分析表明miR2118和miR166可能参与了黄芪的干旱胁迫应答。结论预测的黄芪miRNA、靶基因以及干旱应答miRNA,为理解miRNA在黄芪中的生物学功能提供了重要数据。     

Redistribution of soil water by a saprotrophic fungus enhances carbon mineralization

The desiccation of upper soil horizons is a common phenomenon, leading to a decrease in soil microbial activity and mineralization. Recent studies have shown that fungal communities and fungal-based food webs are less sensitive and better adapted to soil desiccation than bacterial-based food webs. One reason for a better fungal adaptation to soil desiccation may be hydraulic redistribution of water by mycelia networks. Here we show that a saprotrophic fungus (Agaricus bisporus) redistributes water from moist (–0.03 MPa) into dry (–9.5 MPa) soil at about 0.3 cm⋅min⁻¹ in single hyphae, resulting in an increase in soil water potential after 72 h. The increase in soil moisture by hydraulic redistribution significantly enhanced carbon mineralization by 2,800% and enzymatic activity by 250–350% in the previously dry soil compartment within 168 h. Our results demonstrate that hydraulic redistribution can partly compensate water deficiency if water is available in other zones of the mycelia network. Hydraulic redistribution is likely one of the mechanisms behind higher drought resistance of soil fungi compared with bacteria. Moreover, hydraulic redistribution by saprotrophic fungi is an underrated pathway of water transport in soils and may lead to a transfer of water to zones of high fungal activity.Drought is one of the most important and frequent abiotic stresses in terrestrial ecosystems (1). With respect to soil processes, soil desiccation limits microbial activity and decreases soil enzyme activity (2), carbon mineralization (3, 4) and nitrogen mineralization (5). In addition, drought can also alter soil microbial community composition (2, 6).During desiccation and dry periods, soil fungal communities and fungal-based food webs are better adapted to drought than bacterial communities and bacteria-based food webs (7, 8). Bacteria are more strongly restricted than fungi (9), as bacterial activity needs a constant supply of water (10). One reason for the better adaptation of fungi compared with bacteria to low soil water potentials is seen in their strong cell walls, preventing water losses (1). The strength of fungal cell walls can even be enhanced by cross-linking of polymers and thickening under stress. Another reason for the better adaptation of fungi to soil desiccation might be hydraulic redistribution of water by mycelia networks. Hydraulic redistribution is defined as the passive transport of water in soils through organisms along a gradient in soil water potential and was first observed for plant roots (11). Hydraulic redistribution through plant roots improves plant survival and nutrient uptake by extending the life span and activity of roots (12) and by favoring decomposition of soil organic matter (13). Mycorrhiza fungal hyphae can also relocate water along gradients in soil water potential (12, 14–16). In addition, some studies reported the transport of nutrients and water over larger distances (>1 m) by saprotrophic fungal hyphae in nonsoil systems. Further, water leakage from hyphae into dry growth medium was observed (17). The water transport in hyphae was attributed to gradients in osmotic potentials (18–22).Saprotrophic fungi are main regulators of soil nutrient cycling, litter decomposition, and soil respiration due to their specific enzymatic activities (23, 24) and due to the high density of hyphae in soil (up to 800 m⋅g⁻¹ soil) (25), and especially in litter layers. The ability of saprotrophic fungi to distribute water would provide a direct and fast connection between water and nutrient sources in soils that would be hardly accessible to bacteria. This could have an enormous impact on decomposition processes under drought conditions.Here, we show the potential of the saprotrophic fungus Agaricus bisporus for hydraulic redistribution and impact of water redistribution on carbon mineralization in a desiccated soil.     

国家食品药品监督管理总局国家药品标准修订件——盐酸洛美利嗪

以9份转ABP9基因春小麦株系UC₄-1～UC₄-9及其受体亲本宁春4号为材料,在雨养和灌溉条件下,对这些材料的主要农艺性状和部分生化指标进行了测定,采用隶属函数值法和抗旱性度量（D）值法对其抗旱性进行了综合评价,并利用灰色关联度法对相关抗旱性状与抗旱指数之间的关联度进行了分析评价。结果表明：6份转基因小麦的抗旱性较受体亲本宁春4号增强,3份材料的抗旱性较非转基因春小麦品种定西35增强;各农艺性状和生化指标与抗旱指数的关联度从高到低依次分别为株高、单穗粒重、穗长、SOD活性、穗粒数、结实小穗数、有效分蘖数、POD活性、千粒重、脯氨酸含量、MDA含量。     

Long‐term exogenous application of melatonin delays drought‐induced leaf senescence in apple

To examine the potential roles of melatonin in drought tolerance, we tested the effects of its long‐term exogenous application on ‘Hanfu’ apple (Malus domestica Borkh.). When 100 μm melatonin was added to soils under drought conditions, the resultant oxidative stress was eased and leaf senescence was delayed. This molecule significantly reduced chlorophyll degradation and suppressed the up‐regulation of senescence‐associated gene 12 (SAG12) and pheophorbide a oxygenase (PAO). Such treatment also alleviated the inhibition of photosynthesis brought on by drought stress. We also investigated quenching and the efficiency of Photosystem II (PSII) photochemistry under dark and light conditions and found that melatonin helped to maintain better function of PSII under drought. The addition of melatonin also controlled the burst of hydrogen peroxide, possibly through direct scavenging and by enhancing the activities of antioxidative enzymes and the capacity of the ascorbate–glutathione cycle. Thus, understanding this effect of melatonin on drought tolerance introduces new possibilities to use this compound for agricultural purposes.     

应用近红外反射光谱技术测定油菜芽期耐旱性的研究

针对油菜芽期耐旱鉴定，提出了用近红外反射光谱技术（NIR法）预测油菜吸胀24 h电导率、PEG模拟干旱条件下的相对发芽率、相对鲜重和鲜重耐旱指数等4个芽期耐旱相关性状的方法。以采集的49份不同耐旱水平甘蓝型油菜近红外光谱数据为基础，采用偏最小二乘法和多元回归算法建立了最优定标模型，并获得较高的决定系数(0.71～0.86)和较低的标准误差(1～15.65)。验证集评估结果表明，NIR法与室内鉴定法测定油菜4个芽期耐旱相关性状无显著差异，且具有极显著的相关关系(决定系数0.72～0.89)。研究表明,近红外光谱技术用于油菜芽期耐旱性鉴定是可行的，可用于耐旱育种早代选择。     

Empirical evidence suggests adverse climate events have not affected Australian women's health and well‐being

Objective: To compare the health and well‐being of women by exposure to adverse climate events. An Exceptional Circumstance declaration (EC) was used as a proxy for adverse climate events. The Australian government may provide financial support to people living in EC areas, i.e. areas experiencing a one in 20–25 year event (drought, flood or fire) that results in a severe, extended downturn in farm or farm‐related income. Methods: Data from 6,584 53–58 year old non‐metropolitan women participating in the 2004 survey of the Australian Longitudinal Study on Women's Health (ALSWH) were linked to EC data. Generalised linear models were used to analyse differences in SF‐36 General Health (GH) and Mental Health (MH) and perceived stress by EC for all women. Models were adjusted for demographic, health‐related and psychosocial factors potentially on the pathway between EC and health. Given that the effects on health were expected to be greater in vulnerable people, analyses were repeated for women with worse socioeconomic circumstances. Results: GH, MH and stress did not differ for the 3,366 women in EC areas and 3,218 women in non‐EC areas. GH, MH and stress were worse among vulnerable women (who had difficulty managing on available income) regardless of EC. Conclusion and implications: This research adds to the existing literature on climate change, associated adverse climate events and health, by suggesting that multiple resources available in high income countries, including government support and individual psychosocial resources may mitigate some of the health impacts of adverse climate events, even among vulnerable people.     

Regional drought-induced reduction in the biomass carbon sink of Canada's boreal forests

The boreal forests, identified as a critical "tipping element" of the Earth's climate system, play a critical role in the global carbon budget. Recent findings have suggested that terrestrial carbon sinks in northern high-latitude regions are weakening, but there has been little observational evidence to support the idea of a reduction of carbon sinks in northern terrestrial ecosystems. Here, we estimated changes in the biomass carbon sink of natural stands throughout Canada's boreal forests using data from long-term forest permanent sampling plots. We found that in recent decades, the rate of biomass change decreased significantly in western Canada (Alberta, Saskatchewan, and Manitoba), but there was no significant trend for eastern Canada (Ontario and Quebec). Our results revealed that recent climate change, and especially drought-induced water stress, is the dominant cause of the observed reduction in the biomass carbon sink, suggesting that western Canada's boreal forests may become net carbon sources if the climate change-induced droughts continue to intensify.