玉米(Zea mays)是集粮食、饲料和工业原料于一身的重要农作物。开花期是作物适应不同生态环境及产量的关键决定因素。玉米开花期由营养生长时相转变和成花转变决定, 是植物内部因素(遗传因子和植物激素等)和外部环境因素共同作用的结果。鉴于玉米开花期性状的重要性, 该文从控制玉米开花期2次时相转变的组织结构基础、生理基础、遗传基础以及分子调控机理等方面系统总结了玉米开花期的遗传调控机制, 以及关键开花调控因子对玉米区域适应性的重要性, 并对玉米花期性状研究和应用的重点方向进行了讨论, 旨在加深我们对玉米开花期遗传调控的理解, 为培育广适的玉米新品种提供理论依据。

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), one of the most commercially important tree species in western North America and one of the most valuable timber trees worldwide, was introduced to Europe in 1827. It became a major species for afforestation in Western Europe after WWII, currently grows in 35 countries on over 0.83 million ha and is one of the most widespread non-native tree species across the continent. A lower sensitivity to drought makes Douglas-fir a potential alternative to the more drought-sensitive Norway spruce so its importance in Europe is expected to increase in the future. It is one of the fastest growing conifer species cultivated in Europe, with the largest reported dimensions of 2.3 m in diameter and 67.5 m in height. Pure stands have high productivity (up to 20 m³ ha⁻¹a⁻¹) and production (over 1000 m³ ha⁻¹). The species is generally regenerated by planting (initial stocking density from less than 1000 seedlings ha⁻¹ to more than 4000 ha⁻¹), using seedlings of European provenance derived from seed orchards or certified seed stands. As the range of end-uses of its wood is very wide, the rotation period of Douglas-fir is highly variable and ranges between 40 and 120 years. When the production of large-sized, knot-free timber is targeted, thinnings are always coupled with pruning up to 6 m. There is an increasing interest in growing Douglas-fir in mixtures and managing stands through close-to-nature silviculture, but the species’ intermediate shade tolerance means that it is best managed through group selection or shelterwood systems.

Non-photosynthetic components within a forest ecosystem account for a large proportion of the canopy but are not involved in photosynthesis. Therefore, the accuracy of gross primary production (GPP) estimates is expected to improve by removing these components. However, their influence in GPP estimations has not been quantitatively evaluated for deciduous forests. Several vegetation indices have been used recently to estimate the fraction of photosynthetically active radiation absorbed by photosynthetic components (

) for partitioning

{\mathit{APAR}}_{\mathit{green}}

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(photosynthetically active radiation absorbed by photosynthetic components). In this study, the enhanced vegetation index (EVI) estimated

{\mathit{FAPAR}}_{\mathit{green}}

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and to separate the photosynthetically active radiation absorbed by photosynthetic components (

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) from total APAR observations (

{\mathit{APAR}}_{\mathit{total}}

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) at two deciduous forest sites. The eddy covariance-light use efficiency (EC-LUE) algorithm was employed to evaluate the influence of non-photosynthetic components and to test the performance of

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in GPP estimation. The results show that the influence of non-photosynthetic components have a seasonal pattern at deciduous forest sites, large differences are observed with normalized root mean square error (RMSE^*) values of

{\mathit{APAR}}_{\mathit{green}}

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-based GPP and

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-based GPP between tower-based GPP during the early and end stages, while slight differences occurred during peak growth seasons. In addition, daily GPP estimation was significantly improved using the

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-based method, giving a higher coefficient of determination and lower normalized root mean square error against the GPP estimated by the

{\mathit{APAR}}_{\mathit{total}}

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-based method. The results demonstrate the significance of partitioning

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from

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for accurate GPP estimation in deciduous forests.

Forests are exposed to changing climatic conditions reflected by increasing drought and heat waves that increase the risk of wildfire ignition and spread. Climatic variables such as rain and wind as well as vegetation structure, land configuration and forest management practices are all factors that determine the burning potential of wildfires. The assessment of emissions released by vegetation combustion is essential for determining greenhouse gases and air pollutants. The estimation of wildfire-related emissions depends on factors such as the type and fraction of fuel (i.e., live biomass, ground litter, dead wood) consumed by the fire in a given area, termed the burning efficiency. Most approaches estimate live burning efficiency from optical remote sensing data. This study used a data-driven method to estimate live burning efficiency in a Mediterranean area. Burning severity estimations from Landsat imagery (dNBR), which relate to fuel consumption, and quantitative field data from three national forest inventory data were combined to establish the relationship between burning severity and live burning efficiency. Several proxies explored these relationships based on dNBR interval classes, as well as regression models. The correlation results between live burning efficiency and dNBR for conifers (R = 0.63) and broad-leaved vegetation (R = 0.95) indicated ways for improving emissions estimations. Median estimations by severity class (low, moderate-low, moderate-high, and high) are provided for conifers (0 .44 − 0.81) and broad-leaves (0.64 − 0.86), and regression models for the live fraction of the tree canopy susceptible to burning (< 2 cm, 2 − 7 cm, > 7 branches, and leaves). The live burning efficiency values by severity class were higher than previous studies.

Experiencing urban green and blue spaces (GBSs) can be a nature-based solution to improve mental well-being and cope with negative moods for people exposed to PM_2.5 pollution. In this study, a total of 1257 photos were collected to recognize their posted emotions of Sina Weibo users from 38 parks in 22 cities in Northeast China in 2021, when atmospheric PM_2.5 and landscape metrics were evaluated for GBSs of each park. Autumn and winter had heavy atmospheric PM_2.5 pollutions in resource-dependent cities of Liaoning. Net positive emotions (happy minus sad scores) decreased in larger green spaces. The perception of blue space countered the presentation of sadness only for a limited period over four seasons. High elevation decreased the level of happiness presented in winter. Overall, this study confirms that visiting large urban green spaces at low elevations can benefit the perception of positive sentiments for people exposed to PM_2.5 in autumn. For planning urban forests in Northeast China, more green spaces should be constructed in cities in southern Jilin province to alleviate air PM_2.5 pollution and gain better well-being of local people.

Selective logging is well-recognized as an effective practice in sustainable forest management. However, the ecological efficiency or resilience of the residual stand is often in doubt. Recovery time depends on operational variables, diversity, and forest structure. Selective logging is excellent but is open to changes. This may be resolved by mathematical programming and this study integrates the economic-ecological aspects in multi-objective function by applying two evolutionary algorithms. The function maximizes remaining stand diversity, merchantable logs, and the inverse of distance between trees for harvesting and log landings points. The Brazilian rainforest database (566 trees) was used to simulate our 216-ha model. The log landing design has a maximum volume limit of 500 m³. The nondominated sorting genetic algorithm was applied to solve the main optimization problem. In parallel, a sub-problem (p-facility allocation) was solved for landing allocation by a genetic algorithm. Pareto frontier analysis was applied to distinguish the gradients α-economic, β-ecological, and γ-equilibrium. As expected, the solutions have high diameter changes in the residual stand (average removal of approximately 16 m³ ha⁻¹). All solutions showed a grouping of trees selected for harvesting, although there was no formation of large clearings (percentage of canopy removal < 7%, with an average of 2.5 ind ha⁻¹). There were no differences in floristic composition by preferentially selecting species with greater frequency in the initial stand for harvesting. This implies a lower impact on the demographic rates of the remaining stand. The methodology should support projects of reduced impact logging by using spatial-diversity information to guide better practices in tropical forests.

The angiosperm family Cactaceae, a member of the Caryophyllales, is a large and diverse group of stem succulents comprising 1438-1870 species within approximately 130 genera predominantly distributed from northern Canada to Patagonia. Four centers of diversity from Central and North America (Chihuahua, Puebla- Oaxaca, Sonora-Sinaloan, and Jalisco) and three centers of diversity from South America (Southern Central Andes, Caatinga, and Mara Atlantica) have played a pivotal role in disbursing cacti around the globe. Mexico is considered the richest area in cacti species with close to 563 species grouped into 50 genera. Approximately 118 species have been domesticated by Mesoamerican people as food crops and for ornamental purposes. Cacti inhabit a wide range of ecosystems and climate regions, ranging from tropical to subtropical and from arid to semiarid regions. Species belonging to the genus Opuntia are the major food crop producers in the family. Cacti have derived characteristics from familial synapomorphies within the Caryophyllales. Reproduction occurs through pollination facilitated by birds, bats, bees, and other insects. Climate variability, whether natural or human-induced threatens global crop production including high temperatures, salinity, drought, flood, changes in soil pH, and urbanization. Cacti have several adaptations that are important for coping with abiotic stresses, such as crassulacean acid metabolism (CAM photosynthesis), as well as modifications to root and stem physiological pathways. This review aims to provide a comprehensive view of the fruit crops in Cactaceae, including their evolution, worldwide distribution, and the environmental factors impacting cultivation.

Fleshy fruits become more susceptible to pathogen infection when they ripen; for example, changes in cell wall properties related to softening make it easier for pathogens to infect fruits. The need for high-quality fruit has driven extensive research on improving pathogen resistance in important fruit crops such as tomato (Solanum lycopersicum). In this review, we summarize current progress in understanding how changes in fruit properties during ripening affect infection by pathogens. These changes affect physical barriers that limit pathogen entry, such as the fruit epidermis and its cuticle, along with other defenses that limit pathogen growth, such as preformed and induced defense compounds. The plant immune system also protects ripening fruit by recognizing pathogens and initiating defense responses involving reactive oxygen species production, mitogen-activated protein kinase signaling cascades, and jasmonic acid, salicylic acid, ethylene, and abscisic acid signaling. These phytohormones regulate an intricate web of transcription factors (TFs) that activate resistance mechanisms, including the expression of pathogenesis-related genes. In tomato, ripening regulators, such as RIPENING INHIBITOR and NON_RIPENING, not only regulate ripening but also influence fruit defenses against pathogens. Moreover, members of the ETHYLENE RESPONSE FACTOR (ERF) family play pivotal and distinct roles in ripening and defense, with different members being regulated by different phytohormones. We also discuss the interaction of ripening-related and defense-related TFs with the Mediator transcription complex. As the ripening processes in climacteric and non-climacteric fruits share many similarities, these processes have broad applications across fruiting crops. Further research on the individual contributions of ERFs and other TFs will inform efforts to diminish disease susceptibility in ripe fruit, satisfy the growing demand for high-quality fruit and decrease food waste and related economic losses.

In the human-dominated epoch of the Anthropocene, nations worldwide are trying to adopt a variety of strategies for biodiversity conservation, including flagship-based approaches. The Asian elephant ( Elephas maximus) plays a pivotal role as a flagship species in India’s biodiversity conservation efforts, particularly within its tropical forest ecosystems. As the country harboring the largest Asian elephant population among the 13 range countries, India’s conservation strategies offer valuable insights for other range countries. This study elucidates India’s elephant conservation paradigm by outlining a historical account of elephant conservation in the country and examining the current administrative and legal frameworks. These are instrumental in implementing strategies aimed at maintaining sustainable elephant populations. Our study also analyzes trends in elephant populations and negative human–elephant interactions, drawing upon data from a centralized government database. Our findings indicate that the elephant population in India is reasonably stable, estimated at between 25,000 and 30,000 individuals. This figure constitutes nearly two-thirds of the global Asian elephant population. India’s elephant population occupies ∼163,000 km ² of diverse habitats, comprising 5% of the country’s land area, with their distribution spread across the northern, northeastern, east-central, and southern regions. This distribution has shown fluxes, particularly in the east-central region, where large-scale elephant dispersals have been observed. Between 2009 and 2020, human–elephant conflicts in India have resulted in an average annual loss of 450 (±63.7) human lives. During the same period, the central and state governments paid an average of US$ 4.79 million (±1.97) annually as ex gratia for property losses. Recognizing the critical nature of these conflicts, India has implemented various measures to manage this pressing conservation challenge. Overall, sustaining the world’s largest extant population of wild elephants in the midst of India’s human-dominated landscapes is enabled by a robust institutional policy and legal framework dedicated to conservation. This commitment is further reinforced by strong political will and a deep-rooted cultural affinity towards elephants and nature, which fosters a higher degree of tolerance and support for conservation efforts.

飘带兜兰(Paphiopedilum parishii)分布范围狭窄,仅在中国、缅甸、泰国以及老挝有少量分布。近年来,因生境破坏和人为滥采而导致飘带兜兰野生种群极度缩减。为开发种内多态性的分子标记用于保护生物学研究,该研究对飘带兜兰4个野生个体经测序、组装、注释获得的叶绿体基因组序列,与已公布的飘带兜兰2个个体的叶绿体全基因组序列进行比对,分析飘带兜兰叶绿体基因组的种内差异。结果表明:(1)飘带兜兰叶绿体基因组具有典型被子植物叶绿体基因组环状四分体结构,基因组长度为154 403～154 809 bp,共编码129个基因,包括78个蛋白质编码基因、39个tRNA基因、8个rRNA基因,以及4个假基因。(2)在飘带兜兰6个个体叶绿体基因组中检测到103～107个SSRs(simple sequence repeats)位,其中21个SSR位具有多态性。此外,在6个个体叶绿体基因组中还检测到60个长序列重,包括17～21个正向重、18～29个反向重、9～16个回文重、4～9个互补重。(3)通过比较6个个体叶绿体基因组序列的核苷酸多样性,共发现70处变异,包括10个SNPs(single nucleotide polymorphism)、60个插入缺失(InDels)。其中,有3个SNP位发生了非同义替换,导致编码功能基因的氨基酸发生改变; 19个插入缺失多态性较高,具有开发为分子标记的潜力。(4)通过计算核苷酸多样性值(P_i)共发现8个有变异的区域,P_i值为0～0.006 32,其中变异度较大的是rps3-rpl22、trnL-UAC-rpl32、rpoB-trnC-GCA以及ycf4,这些高变区可开发为分子标记用于评估飘带兜兰遗传多样性。(5)系统发生分析结果表明,飘带兜兰6个个体叶绿体基因组序列聚在一起,与长瓣兜兰互为姐妹群。综上表明,飘带兜兰叶绿体基因组的SSRs、长序列重、SNPs、InDels以及核苷酸序列呈现了足够的种内多样性,可开发成分子标记用于该种的系统演化及保护生物学研究。

Natural rubber cultivation is one of the main drivers of tropical deforestation and biodiversity loss. This study examines regulatory and socio-economic conditions that increase the susceptibility of rubber plantations to deforestation and degradation, aiming to support zerodeforestation pledges and sustainability commitments made by the natural rubber industry. By combining bottom-up socio-economic survey data from rubber smallholder farmers in Indonesia with top-down spatial datasets on forest loss and degradation, this study identifies factors associated with deforestation, tree cover loss, and degradation of high-risk plantations. In Jambi Province, Indonesia, from 1991 to 2018, the overall tree cover loss in areas adjacent to rubber plantations was positively correlated to plantation size, remoteness (travel time to cities), and distance to the nearest protected areas, indicating that larger, remotely located plantations likely expanded more into forests between 2000 and 2018. Similarly, tropical forest degradation was positively associated with plantation size, travel time to cities, and distance to protected areas. A higher rubber price in the preceding year correlated with increased annual deforestation and forest degradation, whereas lower prices had the opposite effect. These results suggest that monitoring price changes and identifying plantations that are near non-protected forest frontiers could enable early detection and potential mitigation of deforestation threats.

为从湿地松种子园现有的速生材用无性系中选择产脂力强、松脂品质高的优良无性系,并高效利用湿地松良种资源。该研究以湿地松第一代种子园内36个无性系为材料,测定其松脂质量流速以及胸径生长量,进一步采用GC-MS分析其松脂组分,并基于上述指标利用相关性分析、聚类分析对参试的36个无性系进行综合评价。结果表明:(1)共鉴别出了21种松脂成分,包括8种单萜成分和13种二萜成分。(2)相关性分析显示,树脂质量流速(RMR)与单萜含量显著正相关,与枞酸型树脂酸呈弱的负相关,与海松酸型树脂酸无明显关联。(3)从松节油含量、松脂质量流速、枞酸型树脂酸、海松酸型树脂酸4个维度对参试无性系进行聚类分析,可将36个无性系分为三大类,并且各类型间差异显著,第1类的表现要远好于其他两类。(4)在产脂力高的基础上, 6-44、4-11-1、1-38、3-64四个无性系单萜含量高,4-11-1、3-64、2-0420、3-468四个无性系海松酸型树脂酸含量高,而无性系2-173枞酸型树脂酸含量较高。该研究定性分析了湿地松的松脂组分,定量评估了36个无性系的产脂力与组分含量,为湿地松脂用无性系的选择奠定了基础。

为阐明中药库拉索芦荟(Aloe barbadensis)叶的汁液浓缩干燥物的化学成分,该研究采用HPLC-DAD-ESI-IT-TOF-MSⁿ技术,结合对照品对比和文献检索,对其进行系统的定性分析。以水(A)-乙腈(B)为流动相进行梯度洗脱,流速为1.0 mL·min^-1,质谱使用ESI离子源,采用负离子模式分析液质数据。结果表明:(1)首次阐明中药库拉索芦荟中蒽醌类(芦荟大黄素、大黄素甲醚、大黄素-8-O-β-D-吡喃葡萄糖苷)、蒽酮类(芦荟素A、芦荟糖苷A)、色酮类(芦荟新苷D、7-O-甲基芦荟新苷A、altechromone A、芦荟苦素、芦荟新苷G、芦荟新苷C)、α-吡喃酮类(芦荟宁A、芦荟宁B)四类成分的主要化合物的裂解途径。蒽醌类化合物的裂解途径以失去CO₂和CO为主,蒽酮类化合物的裂解途径以己糖苷的裂解和失去CO为主,色酮类化合物的裂解途径以己糖苷的裂解和酯基的水解为主,α-吡喃酮类的裂解途径主要包括己糖苷的裂解、CO₂和H₂O的丢失等。(2)共检测到168种化学成分,参考相关文献、数据库和对照品数据共鉴定/指认了其中的78种化学成分,包括3种蒽醌类成分、29种蒽酮类成分、35种色酮类成分、7种α-吡喃酮类成分、4种其他类成分; 78种化学成分中有23种为新发现的库拉索芦荟叶的化学成分,其中aloinoside D、isoeleutherin、ethylidene-aloenin等14种成分具有抗菌、抗炎或清除自由基等药理活性。该研究结果进一步丰富了中药库拉索芦荟的化学成分信息,为芦荟的药效物质基础研究及质量控奠定了基础。

为探究岩溶区石灰土条件下火龙果的氮肥施用水平对其果实品质的影响,该文模拟岩溶区石灰土土壤环境开展盆栽试验,以“台湾大红”火龙果为材料,在磷(P)、钾(K)分别为0.216、0.324 kg的基础上,设置4种施氮(N)水平(CK、T1、T2、T3),测定21个果实品质指标,比较不同施氮水平的火龙果品质差异,同时利用主成分分析法对11个外观品质指标进行了综合分析。结果表明:(1)施氮可提高果实可溶性糖含量及可溶性固形物含量,降低蛋白质含量及膳食纤维含量,高N处理(T3)与其他处理差异显著; 随施N量增加,果实可滴定酸含量、维生素C含量呈先升后降的趋势,而固酸比随施N量呈先降后升的趋势; 高N处理明显提高了果实的纵径、横径、果形指数及单果重。(2)施N处理降低了火龙果果实N含量,提高了P含量,各处理间的N、P含量差异显著; 果实K含量随着施N量的增加而提高; 施N增加了果实硼(B)含量,降低了果实铜(Cu)含量; 不同处理果实锰(Mn)、铁(Fe)、钙(Ca)、镁(Mg)含量高低排序为T3>T1>CK>T2; 锌(Zn)含量随施N量呈先降低后增加的趋势。(3)高N处理的主成分综合评价得分最高,说明选择桂林岩溶区棕色石灰土种植火龙果时辅以一定量的P肥、K肥,高N处理更有利于提高火龙果品质。因此,在实际生产中需根据种植园的土壤肥力状况进行适当调整。

Self-incompatibility (SI) is an intraspecific reproductive barrier widely present in angiosperms. The SI system with the broadest occurrence in angiosperms is based on an S-RNase linked to a cluster of multiple S-locus F-box (SLF) genes found in the Solanaceae, Plantaginaceae, Rosaceae, and Rutaceae. Recent studies reveal that non-self S-RNase is degraded by the Skip Cullin F-box (SCF)^SLF-mediated ubiquitin–proteasome system in a collaborative manner in Petunia, but how self-RNase functions largely remains mysterious. Here, we show that S-RNases form S-RNase condensates (SRCs) in the self-pollen tube cytoplasm through phase separation and the disruption of SRC formation breaks SI in self-incompatible Petunia hybrida. We further find that the pistil SI factors of a small asparagine-rich protein HT-B and thioredoxin h together with a reduced state of the pollen tube all promote the expansion of SRCs, which then sequester several actin-binding proteins, including the actin polymerization factor PhABRACL, the actin polymerization activity of which is reduced by S-RNase in vitro. Meanwhile, we find that S-RNase variants lacking condensation ability fail to recruit PhABRACL and are unable to induce actin foci formation required for pollen tube growth inhibition. Taken together, our results demonstrate that phase separation of S-RNase promotes SI response in P. hybrida, revealing a new mode of S-RNase action.

The discontinuous geographic distribution pattern of plants in the north temperate zone has been a focus of biogeographic research, especially concerning the mechanisms behind the formation of such a pattern and the spatial and temporal evolution of this intermittent distribution pattern. Hypotheses of boreotropical origin, land bridge migration, and out-of-Tibet have been proposed to explain the formation of the discontinuous distribution pattern. The distribution of Lonicera shows a typical Europe–Asia–North America discontinuous distribution, which makes for a good case study to investigate the above three hypotheses. In this study, we inferred the phylogeny based on plastid genomes and a nuclear data set with broad taxon sampling, covering 83 species representing two subgenera and four sections. Both nuclear and plastid phylogenetic analyses found section Isika polyphyletic, while sections Nintooa, Isoxylosteum, and Coelxylosteum were monophyletic in subgenus Chamaecerasus. Based on the nuclear and chloroplast phylogeny, we suggest transferring Lonicera maximowiczii and Lonicera tangutica into section Nintooa. Reconstruction of ancestral areas suggests that Lonicera originated in the Qinghai–Tibetan Plateau (QTP) and/or Asia, and subsequently dispersed to other regions. The aridification of the Asian interior may have facilitated the rapid radiation of Lonicera in the region. At the same time, the uplifts of the Tibetan Plateau appear to have triggered the spread and recent rapid diversification of the genus on the QTP and adjacent areas. Overall, our results deepen the understanding of the evolutionary diversification history of Lonicera.

ChinaMu is the largest sequence-indexed Mutator (Mu) transposon insertional library in maize (Zea mays). In this study, we made significant improvements to the size and quality of the ChinaMu library. We developed a new Mu-tag isolation method Mu-Tn5-seq (MuT-seq). Compared to the previous method used by ChinaMu, MuT-seq recovered 1/3 more germinal insertions, while requiring only about 1/14 of the sequencing volume and 1/5 of the experimental time. Using MuT-seq, we identified 113,879 germinal insertions from 3,168 Mu-active F₁ families. We also assembled a high-quality genome for the Mu-active line Mu-starter, which harbors the initial active MuDR element and was used as the pollen donor for the mutation population. Using the Mu-starter genome, we recovered 33,662 (15.6%) additional germinal insertions in 3,244 (7.4%) genes in the Mu-starter line. The Mu-starter genome also improved the assignment of 117,689 (54.5%) germinal insertions. The newly upgraded ChinaMu dataset currently contains 215,889 high-quality germinal insertions. These insertions cover 32,224 pan-genes in the Mu-starter and B73Ref5 genomes, including 23,006 (80.4%) core genes shared by the two genomes. As a test model, we investigated Mu insertions in the pentatricopeptide repeat (PPR) superfamily, discovering insertions for 92% (449/487) of PPR genes in ChinaMu, demonstrating the usefulness of ChinaMu as a functional genomics resource for maize.

Drought is a major threat to alfalfa (Medicago sativa L.) production. The discovery of important alfalfa genes regulating drought response will facilitate breeding for drought-resistant alfalfa cultivars. Here, we report a genome-wide association study of drought resistance in alfalfa. We identified and functionally characterized an MYB-like transcription factor gene (MsMYBH), which increases the drought resistance in alfalfa. Compared with the wild-types, the biomass and forage quality were enhanced in MsMYBH overexpressed plants. Combined RNA-seq, proteomics and chromatin immunoprecipitation analysis showed that MsMYBH can directly bind to the promoters of MsMCP1, MsMCP2, MsPRX1A and MsCARCAB to improve their expression. The outcomes of such interactions include better water balance, high photosynthetic efficiency and scavenge excess H₂O₂ in response to drought. Furthermore, an E3 ubiquitin ligase (MsWAV3) was found to induce MsMYBH degradation under long-term drought, via the 26S proteasome pathway. Furthermore, variable-number tandem repeats in MsMYBH promoter were characterized among a collection of germplasms, and the variation is associated with promoter activity. Collectively, our findings shed light on the functions of MsMYBH and provide a pivotal gene that could be leveraged for breeding drought-resistant alfalfa. This discovery also offers new insights into the mechanisms of drought resistance in alfalfa.

2023年中国科学家在植物科学主流期刊发表的论文数量相比2022年大幅提高, 在柱头受体调控十字花科种内和种间生殖隔离, 叶绿体TOC-TIC超级复合物结构, 作物高产、耐逆及抗病机制, 葡萄和柑橘属植物的起源和传播, 现代玉米、谷子和马铃薯种质资源演化等方面取得了重要研究进展。其中, “农作物耐盐碱机制解析及应用”和“新方法实现单碱基到超大片段DNA精准操纵”入选2023年度中国科学十大进展, “植物远缘杂交过程中‘花粉蒙导效应’的分子机制”入选2023年度中国生命科学十大进展。该文总结了2023年度我国植物科学研究取得的成果, 并简要介绍了30项有代表性的重要进展, 梳理了植物科学研究中所使用的实验材料, 以帮助读者了解我国植物科学的发展态势, 进而思考如何更好地开展下阶段研究和服务国家重大战略需求。

互惠合作系统的非对称性和不确定性过去的几十年里,尽管对互惠合作系统稳定性的理解取得了较大的进展,但在解释互惠关系如何保持稳定方面仍然存在两个基本问题。(i)如何解决互惠合作双方之间的资源冲突?(ii)当存在不怎么合作和/或完全不合作的共生体时,为什么合作的共生体没有被不合作的个体竞争排斥掉?过去许多关于互惠稳定性的解释都假设互惠合作双方的相互作用是对称的。然而,在大多数共生关系中,宿主和共生体之间的相互作用在不同水平上表现出不同程度的非对称性。本文我们回顾了互惠合作系统中的三种主要的非对称相互作用：(i)收益非对称,也就是合作双方的实力非对称性;(ii)潜在进化速率非对称性;(iii)宿主和共生体之间的信息非对称性。我们认为,互惠合作系统非对称性有助于解释合作和冲突行为的不确定性(合作与竞争的内生不确定性),以及为什么宿主和共生体都呈现出多样化的表型特征,而合作仍可占主导地位。

在被子植物中,多样的花部特征是为了适应各种选择压力和生态功能。到目前为止,对兰科植物花部特征的生态功能研究主要集中在唇瓣,而从未有对苞片的研究。本研究以一种熊蜂授粉并且提供花蜜报酬的地生或附生兰科植物笋兰(Thunia alba)为研究材料,其大而显著形似舟状的苞片包裹着花蜜距和花梗。我们猜想显著的大苞片能够保护蜜距,抵御盗蜜者。为了验证这一假设,我们通过实验去除苞片,记录传粉者和盗蜜者访花行为的变化,并评估了它们对笋兰繁殖成功的影响。研究结果表明,当苞片被去除后,唯一的传粉者短头熊蜂(Bombus breviceps)转变为盗蜜者,并且被盗蜜的花的比例也显著增加。无论是花苞片被去除的处理组还是未处理的对照组,笋兰都是受传粉者限制的。去除苞片对传粉者的访花频率并没有影响,但是显著降低了笋兰雄性和雌性的繁殖成功率。本研究表明,在复杂的授粉限制的环境压力下,大而显著的苞片可以防止花被盗蜜者盗蜜从而提高笋兰的整体适合度。

高寒草甸的能量分配和蒸散发对青藏高原多年冻土区水循环至关重要。然而,能量分配、蒸散发及其驱动因素的季节变化(冻融循环)仍需要明确。因此,本研究在位于青藏高原风火山流域的高寒草甸进行了为期4年的能量通量(包括潜热和感热)观测,并估算了大气边界参数(包括表面导度,解耦系数和Priestley-Taylor系数)。研究结果表明,研究区日均潜热(27.45 ± 23.89 W/m²)和显热(32.51 ± 16.72W/m²)分别占可利用能量的31.71%和50.14%。在降雨期,更多可利用能量被分配到潜热;而在冻结期,67.54 ± 28.44%的可利用能量分配给显热。显热在降雨期间是潜热的一半,而由于冻结期较低的土壤水分含量及植被盖度,显热在冻结期间是潜热的7倍。研究区年均蒸散发为347.34 ± 8.39 mm/year,接近年均降水量。较低的日均解耦系数(0.45 ± 0.23)和Priestley-Taylor系数(0.60 ± 0.29)表明高寒草甸的蒸散发受水分供应限制。然而,在降雨期由于降水充足,蒸散发受到可利用能量的限制。在过渡期,蒸散发和降水之间存在较大差异,表明在该季节上游冰川和雪的融水通过侧向流动补给到土壤中。本研究的结果表明,在未来模拟多年冻土区水和能量通量时应考虑大气边界参数的季节变化。

在全球变化背景下,管控入侵物种是一项具有挑战性的工作。这主要由于从入侵物种的入侵性推断它们的生态危害存在很大的不确定性。更确切地说,入侵性和生态危害的关系可能依赖于所研究的生态系统,同时这种关系还没有在像青藏高原这样独特的高寒生态系统中被研究过。在这项研究中,我们在青藏高原东南部的一个样带上调查了32种入侵植物。我们将这些入侵物种的生态危害分解为分布范围(R)、局部丰度(A)和个体对本地植物群落的影响(E) 3个组分,并研究了植物性状对这些组分的相对贡献。研究结果表明,入侵植物的入侵性(R × A)和其所产生的危害(R × A × E)没有相关性。这表明这些入侵植物的入侵性不能反映它们对本地群落生态危害的严重性。在青藏高原,R和A共同驱动了入侵性,而R单独驱动了生态危害。植物性状并没有通过这3个组分驱动入侵性和生态危害,只有果实类型(主要是浆果)影响了E。我们的结果表明,驱动入侵性和生态危害的组分的不匹配导致了入侵植物的入侵性不能反映它们的生态危害。因此,关于入侵物种的管控应该优先考虑那些分布广泛的物种或者已经被证实会对本地物种产生负面影响的物种。

亲缘选择在植物从营养分配向繁殖分配转变中的潜在作用根据经典的最优繁殖分配理论,植物生长过程中从营养生长向繁殖分配的转变是突然发生的。一些植物确实如此,这也是农作物产量最大化的一种有效策略。然而,自然界很多植物从营养生长向繁殖分配的转变是渐进发生的。一些修正的生物量分配理论也预测了这种渐变趋势。本研究假设亲缘选择能够改变最优分配理论的预测。通过数学模型,我们研究了正负亲缘选择对植物向繁殖器官分配能量起始时间的影响。基于代价与收益的合理假设,当繁殖器官与营养器官起始生物量比值较高时,处于亲缘选择作用下的植物更可能以一种突变的方式实现从营养生长向繁殖生长的转变。经验数据的观测支持我们的理论预测。这一研究在连接植物生活史与能量分配以及提高农业产量方面具有重要意义。

花表面温度对植物繁殖有重要作用,但花表面温度的空间分布规律仍不清楚,尤其是在高山植物中。为探讨花表面温度空间分布,我们分析了青藏高原东北部冷龙岭海拔3200至4000 m的18种植物的热成像照片,发现在直射辐射环境下花或花序表面温度空间变化很大,大多数花或花序的中央温度比边缘高出约1 °C,最大可达11 °C。太阳辐射和花的形状显著影响花表面温度的空间分布,如温度的空间变化范围、空间变化的标准差以及花中心与边缘部分的温度比值。花冠越大,表面温度的空间变异性越高。菊科植物表面花温及其空间变异性都比较高,花中央温度比边缘温度也比其它观测的物种更高更稳定。大多数物种花中央与边缘部分温度的比值随海拔上升而增大。这些结果表明,在高山植物中花或花序中央区域的热积累可能很普遍,其生态和进化意义有待进一步探索。