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1.
Deciduous trees with high-density wood that occur in dry seasonal tropical regions respond to rainfall seasonality with synchrony in phenophases. However, they may exhibit interannual differences in sy... 相似文献
2.
《林业研究》2021,(4)
Although important,phenological studies comparing congeneric species or the same species growing in different habitats are still scarce for the tropics.Herein,we integrate phylogeny,ecology and biometeorology to verify whether the phenophases of congeneric species Myrcia laruotteana and Myrcia amazonica or Clethra scabra differ when their populations inhabit wetland and drained habitats and to determine what abiotic factors affect the vegetative and reproductive phenophases of these species in distinct habitat patches.We collected data on phenological events of 80 trees for 1 year in Itacolomi State Park,Brazil,and related them to abiotic local factors.Contrary to our expectation,the phenophases of the congeneric species did not differ between habitats,but the reproductive phenophases of C.scabra did and was greater in drained soil.Phenophases of C.scabra were affected by the depth of the water table and maximum temperature in the wetland soil.Insolation,precipitation,maximum temperature and relative humidity influenced Myrcia and Clethra in the drained soil.The differences between C.scabra populations suggest that this species is phenotypically plastic and can present distinct phenophases depending on the habitat it inhabits.On the other hand,the congeneric Myrcia species may have similar phenophases in distinct habitats because of their shared similarities during their evolution.This study provides a better understanding of the ecology of these species and their adaptations to different abiotic conditions.Data of this nature are important in a changing world and can inform strategies for adaptive management. 相似文献
3.
《林业研究》2016,(3)
We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza(L.)Lamk along the Okukubi River, Okinawa Island, Japan.Over 3 years, this species showed the highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. From Kendall's coefficient of concordance, the monthly changes in leaf, stipule, and branch were strongly and significantly concordant among years. Leaf and stipule litterfall could be governed by monthly maximum wind speed, monthly day length, and monthly mean air temperature. Branch litterfall depended on monthly maximum wind speed and monthly rainfall, and increased exponentially with increasing monthly maximum wind speed. Mean total litterfall was 11.8 Mg ha~(-1)yr~(-1), with the largest component being leaf litterfall(65.8 %). Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Mean leaf longevity was 18 months.Flower and mature propagule litterfall might be influenced by monthly mean air temperature, monthly day length and monthly mean air temperature. The average development periods from flower buds to flowers and flower buds to mature propagules were 1 and 8 months, respectively.Except for leaf and branch, all vegetative and reproductive organ litterfall had clear annual cycles. B. gymnorrhiza showed a positive correlation between leaf production and reproductive organ production. 相似文献
4.
Four common agroforestry trees, including both exotic and native species, were used to provide a range of leafing phenologies to test the hypothesis that temporal complementarity between trees and crops reduces competition for water in agroforestry systems during the cropping period and improves utilisation of annual rainfall. Species examined included Melia volkensii, which sheds its leaves twice a year, Senna spectabilis and Gliricidia sepium, which shed their leaves once during the long dry season, and the evergreen Croton megalocarpus. Phenological patterns were examined in relation to climatic conditions in the bimodal rainfall regions of Kenya to identify factors which dictate the intensity of competition between trees and crops.
The main differences in leaf cover patterns were between indigenous and exotic tree species. The Central American species, S. spectabilis and G. sepium, shed their foliage during the dry season before the short rains, whereas the native species, M. volkensii and C. megalocarpus, exhibited reduced leaf cover during both dry seasons. C. megalocarpus was the only species to maintain leaf cover throughout the 2-year experimental period. M. volkensii and S. spectabilis exhibited similar leafing phenology, losing almost all leaf cover during the long dry season (July–October) and flushing before the onset of the ensuing rains. S. spectabilis lost few leaves during the short dry season, whereas M. volkensii shed a greater proportion of its foliage before flushing prior to the long rains (March–July). M. volkensii lost much of its leaf cover during the 1997/1998 short rains (October–February), when soil water content was unusually high. Although essentially evergreen, leaf cover in C. megalocarpus decreased during the dry season and increased rapidly during periods of high rainfall. G. sepium exhibited a period of low leaf cover during the long dry season and did not regain full leaf cover until mid-way through the short rains. The mechanisms responsible for these phenological changes and the implications of tree phenology for resource utilisation and competition with crops are discussed. 相似文献
5.
6.
We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza (L.) Lamk along the Okukubi River, Okinawa Island, Japan. Over 3 years, this species showed the highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. From Kendall’s coefficient of concordance, the monthly changes in leaf, stipule, and branch were strongly and significantly concordant among years. Leaf and stipule litterfall could be governed by monthly maximum wind speed, monthly day length, and monthly mean air temperature. Branch litterfall depended on monthly maximum wind speed and monthly rainfall, and increased exponentially with increasing monthly maximum wind speed. Mean total litterfall was 11.8 Mg ha?1 yr?1, with the largest component being leaf litterfall (65.8 %). Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Mean leaf longevity was 18 months. Flower and mature propagule litterfall might be influenced by monthly mean air temperature, monthly day length and monthly mean air temperature. The average development periods from flower buds to flowers and flower buds to mature propagules were 1 and 8 months, respectively. Except for leaf and branch, all vegetative and reproductive organ litterfall had clear annual cycles. B. gymnorrhiza showed a positive correlation between leaf production and reproductive organ production. 相似文献
7.
Radosław Puchałka Marcin Koprowski Jožica Gričar Rajmund Przybylak 《European Journal of Forest Research》2017,136(2):259-268
We monitored leaf phenology and xylogenesis of 12 Pedunculate oaks in northern Poland in 2014. We hypothesized that the individual trees, which differed in size, age and habitat (tree stand or gap), also diverged in terms of the seasonal patterns of leaf phenology and xylogenesis. The samples used for wood formation observations were collected most frequently during the early leaf phenophases (from March to end of June). The transverse sections of the cambial region were cut with a sledge microtome. We counted the number of cambial cells, measured the width of xylem increment and assessed the timing of xylogenesis and earlywood-vessel formation. We found significant differences in leaf phenology and timing of xylogenesis among individual trees. The smallest differences in wood formation among the trees were observed at the beginning of the vegetation season when the first earlywood vessels were detected (9 days). The dates of completion of the first tangential row of earlywood vessels varied by up to 30 days, while for the completion of the entire earlywood dates varied by up to 32 days. The highest productivity of cambial cells (13 cell layers) was observed around the time of bud swelling at mid-April. In the last days of April, the number of cambial cell layers decreased and subsequently increased again when the leaves were nearly fully expanded at the end of May. To summarize, we observed a high seasonal variability in the number of cambial cell layers. Differences in the time of cessation of cambial activity and xylogenesis amounted to 1 month. We conclude that: (1) oak tree-ring widths and earlywood-vessel sizes and numbers may not be sensitive indicators for early spring temperature and spring defoliation; (2) the missing association between leaf phenophases and xylogenesis as well as the phenological variability may be the reasons for the lack of a clear climatic effect on the above-mentioned parameters. 相似文献
8.
The colonization preference and population trends of larval fig psylla Homotoma ficus L. were studied in Bursa, northwestern Turkey, from March 2000 to July 2001. Homotoma ficus overwintered at the egg stage on terminal buds and lenticels of shoots. Larval emergence occurred on 30th and 11th March
in 2000 and 2001, respectively. Degree-day (DD) accumulations since 1st January indicate that the emergence of first larvae
averaged 47 DD based on the larval developmental threshold of 10.9°C. Although the population trends of Homotoma ficus larvae were affected by temperature and rainfall, there was only significant relationship between larval abundance and temperature.
The first instar larvae significantly preferred the bottom and the inside stipule of leaves. The second instar larvae distributed
not only on expanding green tissues but also on both the upper and lower surface of leaves corresponding to the fig bud development
period. Third to fifth instars colonized significantly greater on the bottom of leaves compared with the stipule and upper
surface. In addition, significant linear relationship was found between fig phenology and cumulative larval counts. The importance
of the colonization preference of larval instars and the use of fig phenology as well as DD for timing of insecticide treatments
are discussed. 相似文献
9.
Maryline Pellerin Anne Delestrade Gwladys Mathieu Olivier Rigault Nigel G. Yoccoz 《European Journal of Forest Research》2012,131(6):1957-1965
A participatory network was set up to study tree phenology in the Western Alps. We used data collected in 2006 and 2007 on birch, ash, hazel, spruce and larch to assess how local air temperature, altitude and other topographic variables influenced dates of budburst and leaf unfolding. Altitude was, as expected, a main predictor variable of budburst and leafing dates with delays ranging from 2.4 to 3.4 days per 100 m. Ash was the only species with strong evidence of a year difference in the altitudinal gradient with the warm year (2007) characterized by a weaker altitudinal gradient. We found a latitudinal gradient in the appearance of budburst for one coniferous species (larch) and curvature affected leafing in ash. Thermal sum (sum of Degree-Days above 0 °C) was increasing with altitude for budburst (birch, ash and larch) and leafing (birch and ash). Understanding of altitude and topography effects in addition to temperature in phenological models should improve projections of future changes in mountain regions. 相似文献
10.
Earlier modeling has suggested that long distance gene flow is of importance in increasing the adaptability of tree populations in a changing climate. In times of warming temperatures, early flowering phenotypes may be favored, because early flowering may be connected to early onset of growth. Long term direct measurements of flowering, pollen cloud and intrapopulation fecundity variations are needed to test this hypothesis. Having one of the furthest transported types of pollen grains, birch may have good potential for long distance gene flow. Our daily observations over eight years, of 30 silver birches (Betula pendula Roth), showed that the onset and duration of flowering phenology was determined by the accumulation of spring temperature sums, but the window for potential long distance gene flow was narrow. The interannual phenology variations were large, the order of timing of female and male catkins in various trees of this monoecious species tended to differ, and the timing of generative and vegetative spring phenologies were not correlated at tree level. Early flowering trees tended to have a higher variation in germinability than later flowering trees. No other connection between timing of phenology of flowering and seed quantity or quality was found. Although stochastic climatic conditions produce interannually variable phenological windows, probability for long distance gene flow from areas differing in timing of spring temperature accumulations may be low in silver birch. Intertree variations in fecundity were high, and the majority of seeds and pollen were produced by only a few trees. Moreover, the amount of seeds produced was positively related to seed germinability, thus large phenotypic fecundity variations may decrease interannual genetic variations in seed sets. 相似文献
11.
甘肃民勤荒漠区植物物候相的持续特征和组合特征 总被引：1，自引：0，他引：1
以民勤荒漠区1974年以来的36种植物的物候观测资料,运用物候频数的统计方法,划分5个物候相,分析物候相的持续特征和组合特征。结果表明:植物的活动期物候相持续日数平均为212天,绿色期物候相持续日数较长,花色期物候相持续日数最短;花色期、挂果期和绿色期3个物候相不同植物之间相互重叠;旱柳的活动期物候相最长,火炬树和芦苇的活动期物候相最短,胡杨和火炬树的绿色期物候相最短,芦苇的秋色期物候相最短;荒漠区不同植物的花色期以及挂果期差异很大。在花色期物候相中,开花始期较早的植物开花末期也相对较早。 相似文献
12.
在河南卢氏油松种子园对46个无性系结实初期和结实盛期开花物候作了观测，结果表明，一般雌球花可授期比授期比雄球花散粉期来得早，持续时间长，散粉期含在可授期内，散粉期和可授期同步性较好；在不同年份开花始期前后相差2-3d，开花始期早晚与当年≥10℃的活动积温有关，由于受花期温度和降雨等因素的影响，不同年份花期长短可相差10d左右，但不存在花期不遇，不同无性系在开花物候上存在很大差异，但在不同年份各无性系在始花时间上序次则相对稳定，无性系内分株间开花物候仅有1-2d的差异，位于树冠北向的雌雄球花各日期在开花频率上与其它3个方位有较大差异。始花期推后1d左右，此外，还研究了开花物候对同步指数的影响，以及不同物候类型授粉效率的差异。 相似文献
13.
We quantified leaf phenologies of saplings and overstory trees of sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.), and the shrub hobblebush viburnum (Viburnum alnifolium Marsh.) in a 72-year-old northern hardwood forest. Seasonal changes in irradiance in the shrub layer, and in the leaf CO(2) exchange of viburnum, and sugar maple and beech saplings were also measured. Leaf expansion occurred earlier in the spring and green leaves were retained later in the autumn in saplings and shrubs than in overstory trees. During the spring light phase (before overstory closure), large CO(2) gains by all three shrub-layer species occurred as a result of a combination of relatively large leaf area, high photosynthetic capacity, and high irradiance. Throughout the summer shade phase, photosynthetic capacity at a given irradiance remained relatively constant, but CO(2) gain was typically limited by low irradiances. Even though irradiance in the shrub layer increased during the autumn light phase as the overstory opened, CO(2) gains were modest compared to springtime values because of declining leaf area and photosynthetic capacity in all three species. The CO(2) gains during the spring light phase, and to a lesser extent during the autumn light phase, may be important to the carbon balance and long-term persistence of saplings and shrubs in the usually light-limited shrub layer of a northern hardwood forest. Therefore, for some late-successional species, leaf phenology may be an important characteristic that permits their long-term persistence in the shrub layer of mature northern hardwood forests. 相似文献
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15.
Vitellaria
paradoxa, known as Shea tree or karité, is one of the dominant trees of agroforestry parklands in Sahelian region with an immense
commercial value. In this study, we examined infestation of fruit-bearing shoots and fruits on two sites in western Burkina
Faso across different reproductive phenophases, crown heights and aspects. The number of infested and healthy shoots and fruits
were counted on 60 reproductively active trees randomly selected from on-year shea trees in each site, using a metal frame
(0.5 × 0.5 m) to mark a fixed area of the canopy for sampling. The shoot and fruit borer was identified as Salebria sp. (Lepidoptera:Pyralidae), which was not reported earlier. The proportion of infested trees and shoots varied significantly
between sites and among reproductive phenophases (P < 0.0001). The site close to the natural forest had the highest infestation rate than distantly located site. Among reproductive
phenophases, the proportions of infested trees and shoots were the highest during flowering and fruit set, respectively. Fruit
infestation also varied significantly between sites, crown heights and aspects (P < 0.001). The site close to the natural forest and the crown with north-east aspect were heavily infested while the bottom
part of the crown had the lowest infestation. As a whole, 49–80% of trees, 24–31% of shoots and 4–15% of fruits were found
infested, depending on the site. These infestation levels combined with precocious flower and fruit abscissions would pose
serious economic losses that justify a call for immediate pest control initiatives. 相似文献
16.
Extensive variation in fractional resorption of mineral elements from plant leaves is still not fully understood. In multi-species forest stands, species leaf fall phenology and leaf constitution may significantly modify the timing of nutrient return to the soil and overall plant nutrient loss. We studied leaf fall and nutrient loss kinetics, and leaf composition in three natural, temperate, deciduous broadleaf forest stands to determine the role of timing of leaf abscission and nutrient immobilization in cell walls on nutrient resorption efficiency of senescing leaves. Nitrogen (N), phosphorus and potassium contents decreased continuously in attached leaves after peak physiological activity during mid-season. Changes in nutrient contents of attached leaves were paralleled by decreases in nutrient contents in freshly fallen leaf litter. In different species and for different nutrients, resorption of nutrients from senescing leaves proceeded with different kinetics. The maximum nutrient resorption efficiency (the fraction of specific nutrient resorbed from the leaves at the end of leaf fall) did not depend on the mid-seasonal nutrient concentration. Species with earlier leaf fall resorbed leaf nutrients at a faster rate, partly compensating for the earlier leaf fall. Nevertheless, the litter-mass weighted mean nutrient contents in leaf litter were still larger in species with earlier leaf fall, demonstrating an inherent trade-off between early leaf fall and efficient nutrient resorption. This trade-off was most important for N. Losses of the non-mobile nutrients calcium and magnesium were unaffected by the timing of leaf fall. There was large variation in the maximum N resorption efficiency among species. Correlations among leaf chemical variables suggested that the maximum N resorption efficiency decreased with the increasing fraction of cell walls in the leaves, possibly due to a greater fraction of N occluded in cell wall matrix. We conclude that species leaf fall phenology and leaf chemistry modify the timing and quantities of plant nutrient losses, and that more diverse forest stands supporting a spectrum of species with different phenologies and leaf types produce litter with more variable chemical characteristics than monotypic stands. 相似文献
17.
落叶松种间及种内和种间杂种家系间的物候变异与早期选择 总被引：5，自引：2，他引：3
对造林后1～3年生7种(变种)落叶松和7个种内和种间杂种家系的9个物候期进行连续定株观察及生长量调查,利用方差分析方法研究落叶松种间、家系间物候期的变异,利用主成分分析方法划分落叶松种(家系)的物候群,利用典型相关分析方法确定物候期与幼林生长量之间的关系.结果表明:除侧枝芽膨大外,落叶松种间、家系间各物候期的变异均达极显著水平.同样,种内个体间、家系内个体间也存在一定的物候期变异,但同种家系内个体间的变异明显小于杂种家系内个体间的变异.兴安落叶松顶芽展叶、抽新梢时间明显早于其他种,封顶也最早;其次是长白落叶松和华北落叶松;朝鲜落叶松和欧洲落叶松的封顶时间比长白和华北落叶松还要迟半个月;日本落叶松顶芽膨大和展叶时间最晚,封顶时间也明显迟于其他种.以日本落叶松为母本的各种间杂种,在物候上多数表现出中间偏母本的特性,而在抗病能力方面较父本有所改善,在抗寒性方面却明显优于母本.日本落叶松生长最快,其次是长白和朝鲜落叶松,而日×长、日×兴杂种生长量超过母本,表现出超亲杂种优势,表明在东北地区落叶松杂种利用潜力巨大.根据主成分聚类结果,可将14份遗传材料分为4个物候型.除侧枝芽开始展叶、完全展叶和抽新梢以外的其他物候因子与生长量之间相关紧密.物候因子对生长量有相当好的预测能力,即顶芽萌动、展叶越早,封顶越迟,生长期越长,对树木的生长越有利. 相似文献
18.
林木种子园生殖系统研究进展 总被引：5，自引：0，他引：5
本文对种子园生殖系统中亲本开花物候、配子产量、球果和种子败育、授粉机制、球花分布对种子园遗传效率的影响及其研究进展作了综述。论述了开花物候、球花产量与配子贡献以及种子园生殖系统遗传效率的关系。不同亲本开花物候及授粉机制的差异限制了亲本之间的基因交流 ,雌雄球花产量、球果败育及其雌雄球花空间分布的差异都会引起亲本配子贡献的变化 ,并最终影响种子园生殖系统的遗传效率。为提高种子园种子的遗传品质和遗传多样性 ,更系统深入地研究种子园生殖系统是必要的 相似文献
19.
[目的]通过对濒危植物水青树的生殖配置进行研究,探讨其生殖与生存之间的权衡关系,揭示其生活史对策及其濒危机制。[方法]对固定样地内的不同径级水青树个体的标准生殖枝生物量进行观测,对不同径级个体的差异采用多重比较分析,对生殖配置(RA)、生殖构件与营养构件生物量采用相关性分析和线性回归分析,对种子数量与千粒质量进行相关性分析。[结果](1)随径级的增大,水青树的生殖和营养投入呈现同增同减的趋势,没有明显的权衡关系;(2)水青树的生殖分配(RA)随径级的变化呈现先上升后下降的趋势;(3)水青树的生殖投入与营养投入、叶生物量之间呈显著正相关,而其RA与营养投入、叶生物量之间呈显著负相关;(4)生殖构件各组分中,种子生物量所占比重均为最小,且远远低于生殖的附属结构(果序轴和果皮);种子数与种子大小之间存在权衡关系。[结论]在构件水平上,水青树的营养投入对生殖投入具有促进作用;其生殖期可划分为生殖初始期、生殖增长期、生殖高峰期和生殖衰退期等4个时期;其种子特征在生殖不同时期分别采取不同的生活史对策,可能是水青树在长期演化发展过程中形成的生殖适应性对策。 相似文献
20.
In a deciduous forest, differences in leaf phenology between juvenile and adult trees could result in juvenile trees avoiding canopy shade for part of the growing season. By expanding leaves earlier or initiating senescence later than canopy trees, juvenile trees would have some period in high light and therefore greater potential carbon gain. We observed leaf phenology of 376 individuals of 13 canopy tree species weekly over 3 years in a deciduous forest in east central Illinois, USA. Our objectives were: (1) to quantify for each species the extent of differences in leaf phenology between juvenile and conspecific adult trees; and (2) to determine the extent of phenological differences between juvenile Aesculus glabra Willd. and Acer saccharum Marsh. trees in understory and gap microhabitats. All species displayed phenological differences between life stages. For 10 species, bud break was significantly earlier, by an average of 8 days, for subcanopy individuals than for canopy individuals. In 11 species, completion of leaf expansion was earlier, by an average of 6 days, for subcanopy individuals than for canopy individuals. In contrast, there were no significant differences between life stages for start of senescence in 10 species and completion of leaf drop in nine species. For eight species, leaf longevity was significantly greater for subcanopy individuals than for canopy individuals by an average of 7 days (range = 4-10 days). Leaf phenology of subcanopy individuals of both Aesculus glabra and Acer saccharum responded to gap conditions. Leaf longevity was 11 days less in the understory than in gaps for Aesculus glabra, but 14 days more in the understory than in gaps for Acer saccharum. Therefore, leaf phenology differed broadly both between life stages and within the juvenile life stage in this community. A vertical gradient in temperature sums is the proposed mechanism explaining the patterns. Temperature sums accumulated more rapidly in the sheltered understory than in an open elevated area, similar to the canopy. Early leaf expansion by juvenile trees may result in a period of disproportionately higher carbon gain, similar to gains made during summer months from use of sun flecks. 相似文献