福建山樱花无性系萌芽展叶物候遗传变异及选择

为划分福建山樱花无性系萌芽展叶物候,在福建省南平市延平区茫荡镇北山村对41个福建山樱花嫁接无性系进行了为期2a的花期观测。结果表明,无性系间萌芽展叶期物候差异极显著。叶芽膨大期、叶芽开放期、展叶始期、展叶盛期的重复力分别为0.732、0.899、0.954、0.958。依据展叶始期、展叶盛期对无性系系统聚类,41个无性系可分为展叶早期型、展叶中期型、展叶晚期型3类,展叶始期到盛期平均时长11d。以先花后叶型为前置条件,盛花期为目标性状,分别从展叶早、中、晚3型中各选择1个无性系作为早中晚3个观花型无性系。

南京地区落叶栎林木本植物叶物候研究

叶物候参数长期以来被认为与植物的碳获取的最大化有关,能反映物种的资源利用策略。温带地区因为寒冷冬天的限制,延长叶寿命成为一些物种进行生长发育和繁衍的基础。为探讨叶寿命延长的可能途径(早出叶、晚落叶,或两者兼有),该研究以南京地区两个落叶栎(Quercusspp.)林为研究对象,观测了其中木本植物的出叶物候、落叶物候,并分析了它们与叶寿命之间的关系。结果发现1)不同物种的出叶开始时间相差较大,出叶早的物种早结束出叶过程;2)不同物种的落叶开始时间相差较大,早开始落叶的物种,落叶持续时间较长,落叶结束时间则相对集中。3)相关分析和回归分析都表明,叶寿命与出叶时间和落叶时间显著关联,但早出叶对叶寿命的延长可能更为重要,因为早出叶相对于晚落叶在物种资源利用上比较具有优势。4)不同物种的出叶时间和落叶时间没有显著相关,可能因为出叶过程和落叶过程是由不同的启动因子引起。这说明延长叶寿命不一定同时通过早出叶和晚落叶来达到。

叶物候、构建消耗和偿还时间对入侵植物碳积累的影响

随着全球经济一体化进程的深入,生物入侵已成为严重的全球性问题之一。外来种入侵打破了物种生存的自然平衡,导致生态系统趋于均质化,并给社会经济发展和人类健康造成了无法估量的损失。然而,目前人们对外来种的入侵机理仍不十分清楚。叶物候如叶片发生时间、凋落时间、及由二者决定的叶寿命和叶片发育进程是植物在季节和非季节性变化的环境中为了获得碳收益所采取的适应策略。叶构建消耗是植物碳收获过程中必要的成本投入,反映了植物在叶片水平上的能量分配策略。偿还时间能在一定程度上反映叶片碳的积累情况。从叶物候、构建消耗和偿还时间入手,分析了入侵植物的资源捕获能力和成本对其碳积累的影响,并提出了今后的研究方向。

构树叶物候持续时间的纬度格局

利用中国物候观测网9个站点记录的构树(Broussonetia papyrifera)叶物候近半个世纪的数据,使用线性回归模型分析构树叶物候持续时间的纬度差异。结果显示,构树叶物候持续时间随纬度增加有明显逐渐缩短的趋势。具体表现为:随着纬度增加,展叶期逐渐提前,落叶期逐渐延迟。对环境因子的重要性进行随机森林回归分析,结果表明,展叶季前的温度是控制构树展叶期和叶持续时间最关键的环境因子,而落叶季前的降水量是落叶期最关键的环境因子,这表明叶物候持续时间的纬度格局是由温度和降水量共同塑造的。结果表明,广布种植物物候存在明显的纬度梯度,以此适应不同的当地环境条件,提高了自身适应性。从地理格局视角,评估纬度对同一物种不同种群叶物候的影响,有助于评估物种未来的分布范围变化及灭绝风险。

不同种源雷公藤叶物候特征比较

以21个不同种源雷公藤为研究对象,观测其一个生长季的叶物候,分析不同种源雷公藤叶物候特征,探讨各叶物候参数之间的相关关系.结果显示:(1)不同种源雷公藤叶物候存在差异.a)不同种源的雷公藤出叶开始时间相差较大,出叶最早种源是福建三明清流(3月28日),出叶最晚种源是广西柳州融水(4月27日),出叶开始时间最早与最晚相差30 d,并且出叶开始时间越早的种源出叶结束时间越早;b)不同种源的雷公藤落叶开始时间相对集中,云南临沧云县为落叶开始最早种源,比最晚开始落叶的浙江金华武义早13 d,而落叶结束时间存在差异,落叶结束时间最早与最晚相差19 d,落叶持续时间越长,落叶结束时间越晚.2)相关分析和回归分析表明雷公藤的出叶时间和落叶时间与叶寿命之间具有显著相关性,出叶时间越早或者落叶时间越晚,叶寿命越长,不过出叶物候与落叶物候之间不存在显著关系.综合雷公藤叶物候观测结果表明,叶寿命较长有利于雷公藤获得竞争优势,对于雷公藤良种筛选和引种驯化有参考价值.

白桦与山杨叶凋落物候的差异及其生态学意义

用凋落物收集法和凋落物候模型研究了白桦(Betula platyphylla)和山杨(Populus davidiana)的叶凋落物候。结果表明:白桦叶凋落显著早于山杨,凋落开始时间和凋落高峰分别比山杨早41和20 d,但它们的叶凋落结束时间基本相同,这导致白桦的凋落期比山杨长42 d。此外,白桦叶凋落集中程度也明显小于山杨,凋落峰值仅是山杨的五分之一。白桦的叶N质量分数较高,碳氮比较低,导致了白桦叶分解较山杨叶快。这体现了处于相同的环境条件,白桦和山杨在能量利用和养分循环方面可能具有不同的生态策略。

浙江古田山亚热带常绿阔叶林叶衰老物候影响因子研究

该文选取浙江省古田山亚热带常绿阔叶林72种木本植物,探究气候因素、系统发育关系和功能性状对亚热带常绿阔叶林叶衰老物候的影响。结果表明,叶变色期在9—12月,落叶期在10—12月。每月落叶物种数与月均温、月均降水量和月均日照时数没有显著相关性,每月叶变色物种数与月均温和月均日照时数呈弱相关;落叶性对叶变色期和落叶期具有显著影响;植物间系统发育关系对叶变色期和落叶期没有显著影响。因此,生物和非生物因子都会影响常绿阔叶树种的叶衰老,这对于提高秋季物候预测模型具有重要价值。

浙江天童常绿阔叶林12种常绿木本植物的落叶格局

落叶格局反映了植物叶片适应环境的生理生态策略,是植物功能群的重要特征。本研究通过跟踪观测枝条上老叶(一年生及以上)和当年生小枝新叶整年的数量动态,揭示了天童地区12种常见常绿阔叶木本植物不同的落叶格局,并且发现同一群落层次内有多种类型存在。根据落叶特性可分为季节性集中落叶型和全年持续性落叶型,其中4个物种表现为春季集中落叶型,2个物种为夏季集中落叶型,1个物种为秋季集中落叶型,1个物种为春秋季集中落叶型,4个物种为全年持续性落叶型;研究还发现阳性物种(包括冠层乔木及林窗下灌木)多为集中落叶型,而耐阴灌木物种多为全年持续性落叶型,并且阳性物种相比于耐阴灌木物种年总落叶比例更大,表明叶片更新率更快。结合当年气候数据及出叶物候,本文讨论了新叶生长、台风干扰及水分等因素对落叶格局的影响。通过对亚热带常绿阔叶林植物落叶格局及其影响因素的研究有望能进一步探索植物对环境的适应策略。

乌鲁木齐市彩叶树种资源及其园林应用调查与分析

乌鲁木齐市彩叶树种共有17科46种,其中秋色叶树种比例最大(39种,占总数的84.78%),常色叶(4种)和春秋色叶树种类(3种)很少。多数秋色叶树种彩叶期集中在10月至11月,但到11月中旬后实际可观赏的彩叶树种类逐渐减少;常色叶和春秋色叶树种彩叶期虽然很长,但在园林彩叶景观中的作用微小。彩叶树种园林配植类型有:孤植、丛植、色块与基础种植、列植、垂直绿化等。主要存在彩叶树种单调;种类比例结构及配植不合理;重区外引种,轻自主选育和本地资源开发;苗木生产不够规范,受市场不良炒作影响大等问题。建议挖掘本地彩叶树种资源,引进急需树种;优化配植,扩大应用范围,提高养护管理水平。

Phenological observations on Larix principis-rupprechtii Mayr. in primary seed orchard

Through 5 years of phenological observations on Larix principis-rupprechtii Mayr. in primary seed orchard and studies on population and individuals of clones, the annual periodic phenological laws were revealed and the annual phe-nological periodic table was drawn up. The correlation between various phenophases, the air temperature and active accumu-lated temperature were analyzed and expounded. The authors also analyzed the similarities and differences of phenophases among clonal individuals as well as the blooming properties of male and female flowers at the same time. This study could pro-vide theoretical reference for working out the production plan of improved varieties and other management measures in seed orchard of Larix principis-rupprechtii.

GF-2影像多特征组合的毛竹林信息精细提取

以福建省永安市天宝岩山地毛竹林为对象,基于高分二号(GF-2)卫星数据提取光谱、纹理及物候特征,比较光谱+纹理、光谱+纹理+物候2种特征组合方案,采取支持向量机(SVM)、最大似然法(MLE)、随机森林(RF)等3种分类方法对毛竹林信息进行专题提取。研究表明:4月份不同森林类型间的光谱特征差异大,是毛竹林信息提取的关键物候期,基于GF-2的10月与4月归一化植被指数(NDVI)的差值、乘积运算构建一种新的叶物候特征指数以适用毛竹林信息的分类提取;增加叶物候特征后有利于提高毛竹林专题信息分类精度,SVM、MLE、RF三种方法的总体分类精度分别提高了0.69%、0.54%、0.63%,Kappa系数达0.79~0.84,其中支持向量机的分类结果最好,对毛竹林信息提取精度达92.75%。

Effects of Nitrogen Deposition on Tundra Vegetation Undergoing Invasion by Deyeuxia angustifolia in Changbai Mountains

In recent years, herbaceous species such as Deyeuxia angustifolia （Kom.） Y. L. Chang has invaded alpine tundra regions of the western slope of the Changbai Mountains. Because atmospheric nitrogen deposition is predicted to increase under a warming climate and D. angustifolia is sensitive to nitrogen addition, field experiments were conducted from 2010 to 2013 to determine the effect of increased nitrogen deposition on the mechanisms of D. angustifolia invasion. The goal of this study is to evaluate the impact of increased nitrogen deposition on the changes in alpine tundra vegetation （consisting mostly of Rhododendron chrysanthum Pall. and Vaccinium uliginosum Linn.）. The results showed that： 1） simulated nitrogen deposition affected overall characteristics and structure of R. chrysanthum and E uliginosum communities and had a positive impact on the growth of tundra vegetation invaded by 1）. angustifolia; 2） R. chrysanthum was more resistant to invasion by D. angustifolia than V.. uliginosum; 3） simulated nitrogen deposition could improve the growth and enhance the competitiveness of D. angustifolia, which was gradually replacing R. chrysanthum and V. uliginosum and might become the dominant species in the system in future, transforming alpine tundra into alpine meadow in the Chanebai Mountains.

Analysis on the Phenophase Characteristics of Zhengdan958 and Xianyu335 in North of Huanghuaihai Region

[Objective] The study is aimed to timely grasp the growth and develop- ment process of summer maize and comprehensively evaluate the impact of envi- ronmental factors on the growth and development of maize in north Huanguaihai re- gion. [Method] The phenophase, leaf unfolding rate, grain filling rate and yield char- acteristics of Zhengdan 958 and Xianyu 335 were analyzed at N 37°53′, E115°42′. [Result] The summer corn Zhengdan 958 and Xianyu335 emerged in 6 days after sowing with the growing period of 111 d, grain-filling stage lasting 66 days, and the leaf unfolding rate and grain filling rate were accelerated with the increase of tem- perature. In the last 6 d before harvest （October 5-11）, Zhengdan 958 and Xi- anyu335 contributed to the yield by 6.61% and 4.20%, respectively. The two crops a year cropping system made it hard for the summer maize to achieve maturing harvest in north Huanghuaihai region. [Conclusion] The maize production could be significantly improved through selecting early maturing varieties, early sowing, timely late harvest, ensuring maize effective accumulated temperature and sufficient grout- ing time after pollination.

Effect of contrasting climates on antioxidant and bioactive constituents in five medicinal herbs in Western Himalayas

To understand the effect of climate change on constitutive antioxidant and biochemical metabolites in Western Himalayas, five medicinal herbs were selected and grown at two altitudes in Jammu(305 m) and Srinagar(1730 m) with subtropical and temperate climates, respectively.Significant variations were observed in phenols and flavonoids in Hypericum perforatum L., Matricaria chamomilla L., Thymus vulgaris L., Cynara cardunculus L. and Echinacea purpurea L. growing at two locations. High altitude temperate site show variable(up to 13 fold) increase in their content.Proteins(1.3- 1.8 times), sugars(2.8- 4.1 times) and free amino acid(1.04- 1.22 times) were also higher at Srinagar(1730 m). Within these plants, H.perforatum and M. chamomilla have shown higher accumulation of phenols, xanthophylls and proline even at subtropical environment in Jammu(305 m)suggesting potential for increasing their geographical area. The results demonstrate that changing environmental conditions significantly affect the bioactive constituents, which accumulate as a defence strategy by these temperate plants. Their medicinal significance during climate change scenario has also been discussed.

Coloration and phenology manifest nutrient variability in senesced leaves of 46 temperate deciduous woody species

Senesced-leaf nutrient concentrations vary signifcantly among coexisting plant species refecting different leaf nutrient use strategies.However,interspecifc variation in senesced-leaf nutrients and its driving factors are not well understood.Here,we aimed to determine interspecifc variation and its driving factors in senesced-leaf nutrients.We explored interspecifc variation in carbon(C),nitrogen(N)and phosphorus(P)concentrations in newly fallen leaves of 46 coexisting temperate deciduous woody species across the Maoershan Forest Ecosystem Research Station,Northeast China.The relative importance of 10 biotic factors(i.e.mycorrhiza type,N-fxing type,growth form,shade tolerance,laminar texture,coloring degree,coloring type,peak leaf-coloration date,peak leaf-fall date and end leaf-fall date)was quantifed with the random forest model.N and P concentrations varied 4-and 9-fold among species,respectively.The high mean N(15.38 mg·g^(−1))and P(1.24 mg·g^(−1))concentrations suggested a weak N and P limitation in the studied forest.Functional groups had only signifcant effects on specifc nutrients and their ratios.P concentration and N:P were negatively correlated with peak and end leaf-fall dates for the ectomycorrhiza species group.Brighter-colored leaves(red>brown>yellow>yellow-green>green)tended to have lower N and P concentrations and higher C:N and C:P than darker-colored leaves.The random forest model showed that autumn coloration and leaf-fall phenology contributed 80%to the total explanation of nutrient variability among species.The results increase our understanding of the variability in senesced-leaf nutrients as a strategy of woody plant nutrition in temperate forests.

Litterfall seasonality and adaptive strategies of tropical and subtropical evergreen forests in China

Tropical and subtropical evergreen broad-leaved forests(EBFs)and needle-leaved forests(ENFs)in China exhibit complex leaf shedding strategies in responses to soil water availability,vapor pressure deficits(VPDs)and sunlight availability.However,the seasonal variations and triggers of litterfall differ significantly in tropical/subtropical forests,and there are still many uncertainties.Herein,we aim to explore the distinct climatic factors of seasonal litterfall in a climate–phenology correlation framework.We collected seasonal litterfall data from 85 sites across tropical/subtropical China and used linear correlation coefficients between sunlight and rainfall to partition synchronous/asynchronous climates.Additional phase analysis and structural equation model analysis were conducted to model the climatic triggers of tropical phenology.Results indicated two types of tropical litterfall phenology under two types of climates.In synchronous climates,where seasonal sunlight and rainfall are positively correlated,the litterfall peak of the unimodal phenology and the first litterfall peak of the bimodal phenology both happen at the end of dry season.The second litterfall peak of the bimodal phenology occurs at the end of rainy season due to water stress.In asynchronous climates,where seasonal sunlight and rainfall are negatively correlated,VPD shows consistent seasonal variations with incoming sunlight.The leaf senescence is accelerated at the end of dry season by higher VPD;while soil water deficit is in anti-phase with sunlight and mainly controls the second litterfall peak of the bimodal phenology in EBF.Our findings provide an important reference for modeling tropical phenology in Earth system models.

Seasonal variation in native hydraulic conductivity between two deciduous oak species

Aims Mechanisms of plant drought resistance include both tolerance and avoidance.Xylem vulnerability to embolism and turgor loss point are considered traits that confer tolerance,while leaf abscission and deciduousness characterizes the avoidance strategy.While these mechanisms are thought to trade-off expressing a continuum among species,little is known on how variation in the timing and duration of leaf shedding in response to drought affect the relationship between xylem and leaf tolerance.In the present study,we explored the extent to which drought tolerance differs between two oak(Quercus)species that exhibit different leaf shedding behaviours.Particularly,we predicted that Q.deserticola Trel.,which loses leaves at the end of the dry season(late-deciduous)and is thus exposed to a greater risk of cavitation,would be more drought tolerant and more conservative in its water use than Q.laeta Liebm.,which loses its leaves for only a short period of time in the middle of the dry season(brevideciduous).Methods The study was conducted in central Mexico in a single population of each of the two oak species,separated from each other by a distance of 1.58 km,and by an altitudinal difference of 191 m.Quercus deserticola(late deciduous)is more frequent down slope,while Q.laeta(brevideciduous)tends to occur at higher elevations along the gradient.We assessed seasonal differences(rainy versus dry season)in native stem hydraulic conductivity,and tested for variation in xylem vulnerability to cavitation,leaf water use and leaf turgor loss point between the two species.Important Findings The two oak species did not differ in traits conferring drought tolerance,including xylem vulnerability to embolism,leaf turgor loss point,or stomatal conductance.However,both species had different performance during the dry season;the brevideciduous species had lower negative impact in the xylem function than the late-deciduous species.Overall,seasonal changes in plant physiological performance between the two oak species were determined by a reduction in the canopy leaf area.

Warming increases soil carbon input in a Sibiraea angustata-dominated alpine shrub ecosystem

Plant-derived carbon(C)inputs via foliar litter,root litter and root exudates are key drivers of soil organic C stocks.However,the responses of these three input pathways to climate warming have rarely been studied in alpine shrublands.By employing a 3-year warming experiment(increased by 1.3℃),we investigated the effects of warming on the relative C contributions from foliar litter,root litter and root exudates from Sibiraea angustata,a dominant shrub species in an alpine shrubland on the eastern Qinghai-Tibetan Plateau.The soil organic C inputs from foliar litter,root litter and root exudates were 77.45,90.58 and 26.94 g C m^(-2),respectively.Warming only slightly increased the soil organic C inputs from foliar litter and root litter by 8.04 and 11.13 g C m^(-2),but significantly increased the root exudate C input by 15.40 g C m^(-2).Warming significantly increased the relative C contributions of root exudates to total C inputs by 4.6%but slightly decreased those of foliar litter and root litter by 2.5%and 2.1%,respectively.Our results highlight that climate warming may stimulate plant-derived C inputs into soils mainly through root exudates rather than litter in alpine shrublands on the Qinghai-Tibetan Plateau.