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1.
巴山冷杉的种实特性及其种子萌发力   总被引:3,自引:0,他引:3  
对我国特有树种巴山冷杉(Abies fargesi)的球果长、球果宽、球果重量、单果出种量等球果特征和种子长、种子宽、种子厚和种子重等种子特性进行了分析,通过发芽实验测定了种子萌发能力.结果表明,巴山冷杉球果平均长5.37±0.75cm,球果宽3.01±0.32cm,球果重量18.93±6.06g,单果出种量59-567粒,种子长1.08-8.68mm,种子宽1.16-6.42mm,种子厚0.6-3.48mm,千粒重7.30g.各项球果特征指标和种子特征指标在种群内和种群间均存在显著差异,单果出种量在不同种群的频数分布格局不同.不同母树的种子发芽率和发芽势不等,且萌发速率也不相同.巴山冷杉种子败育率高,参试种子的空粒率75.79%.  相似文献   

2.
濒危植物银杉种子特征的研究   总被引:16,自引:3,他引:13       下载免费PDF全文
同一株银杉的不同珠果的出种量没有明显差异,说明就同一植株而言,其有性生殖是同步,球果的发育程度比较接近。银杉种子的平均重量0.00197g,仅为乔木树种种子平均重量的6%。种子中空粒比例达16.24%,反映出较高的种子败育率,饱满的种子中有生活力者仅占53.5%,银杉种子的吸水过程有3个明显的阶段,0-1h是急剧吸水阶段,1-9h吸水基本停滞9h到14d吸水果又呈递增趋势。在同样贮藏条件下,播种环  相似文献   

3.
濒危植物银杉的结实特性及动物对果实的危害性   总被引:16,自引:3,他引:13       下载免费PDF全文
银杉结实量的年际波动很大,具有明显的大小年之分,一般在2~3个小年之后为1~2个大年。银杉母株的结实量在不同的母树间差别很大,平均单株的球果数仅为66个。球果结实量在树冠南北侧有差异,南侧球果数占球果总数的60%;球果结实量的垂直分异明显,树冠中、上部的球果数占总量的90%以上。松鼠对树上尚未完全成熟的银杉果实的取食危害是长期性的,对银杉种子种群造成严重破坏。以1995年为例,被啃食的球果数占球果总数的比重可达15%左右。试验表明,土壤种子库中地表的银杉种子几乎全部被动物取食,种子埋藏深度增加有利于逃避动物的取食。  相似文献   

4.
梵净山冷杉(Abies fanjingshanensis)为国家一级保护濒危植物。为了揭示梵净山冷杉球果发育和成熟过程的性状特征,以确定成熟球果的适宜采种期。该研究对梵净山冷杉自然生长区内成年结实母树的球果进行跟踪观测和定期采集,通过物理解剖和形态学参数测定,比较分析不同采种期梵净山冷杉的球果、种鳞和种子的性状差异。结果显示:(1)梵净山冷杉的球果每年7月中旬开始形成,10月中旬开始成熟,发育早期至发育后期球果的长度和宽度显著增加,发育后期至成熟期形态和颜色均无明显变化。(2)成熟球果平均长、宽、鲜重、干重和相对含水量分别为7.18 cm、3.84 cm、36.98 g、20.33 g和45.06%。(3)成熟球果的平均种鳞层数为30.76层,种鳞总数为250.67片,平均出种量436.67粒,平均种子饱满率82.49%。(4)成熟球果基部、中部、上部的种子性状不同,且球果中部的种子性状参数最大,饱满率最高,种子平均长、宽、厚分别为9.14、2.30、2.37 mm,千粒重11.44 g。研究表明,梵净山冷杉的球果从形成至成熟过程约3个月,成熟球果的最佳采种时间为10月下旬,发育后期和成熟球果的形态和颜色差异不明显,不能以颜色和形态作为球果成熟的判定依据;种鳞与球果的发育和成熟同步,球果中部的种鳞能够完全发育,且形状参数最大,孕育的种子最饱满;梵净山冷杉成熟球果出种量大、饱满率高,但是种子小、重量轻。  相似文献   

5.
濒危植物秦岭冷杉生殖生态学特征   总被引:14,自引:0,他引:14       下载免费PDF全文
张文辉  许晓波  周建云 《生态学报》2006,26(8):2417-2424
为了探索秦岭冷杉种群生殖生态学主要特征,通过样地调查、固定样地观测和室内实验分析,系统研究了秦岭地区5个秦岭冷杉(Abies chensiensis)种群生殖特性及其与环境因素的关系,结果表明,5个不同生境的种群都具有结实能力,海拔1500~1600m之间,秦岭冷杉球果的产量较高;各种群球果主要分布在树冠中上部和东、南、西方向;球果以中部产生饱满种子比率最高;秦岭冷杉种子千粒重为43.2g,其中具有生活力者占44.8%,种子的平均含水量为5.7%左右;在天然林散落条件下,种子库的萌发率仅为6.1%,霉坏、搬迁率93.9%;人工播种条件下,种子发芽率在苗圃内高于天然条件下,中低海拔高于高海拔地区。天然条件下,由种子转化成幼苗的过程是秦岭冷杉种群生活史的脆弱环节。秦岭冷杉林经营管理要以就地保护为主,促进种群生殖;要通过森林经营措施,为林下种子萌发和幼苗创造条件;种子脱落后,要及时扰动林下灌木、草本,使种子能够顺利落地,促其发芽成苗;种子大年要注意采种、育苗,扩大人工种群;速生丰产林培育应该以中低海拔的阴坡为主。  相似文献   

6.
濒危植物秦岭冷杉结实特性的研究   总被引:18,自引:1,他引:17       下载免费PDF全文
 秦岭冷杉(Abies chensiensis) 是松科冷杉属常绿乔木,为我国特有珍稀濒危植物。该文在秦岭冷杉分布最为集中的秦岭地区分高、低2个海拔高度采集当年球果和种子, 通过野外观察、室内实验和对比分析,研究秦岭冷杉的结实特征以及球果和种子的基本性状,并探讨这些特征在不同海拔高度的差异。结果表明,与冷杉属其它树种相比,秦岭冷杉球果和种子较大、单果种子数较多,但空粒多、饱满度低。自然状况下饱满度为12.0%,人工目视分选后饱满度21.6%,风选后可达到38.1%,其余种子大部分为空粒、涩粒,有少量虫粒。随海拔高度增加,秦岭冷杉天然群体成龄个体中结实母树比例降低,结实量减少。秦岭冷杉总体结实母树比例为55%,低海拔处结实母树比例较高,为76%,高海拔结实母树比例为34%。秦岭冷杉单株母树的平均结实量为113个,结实量小于100个的母树占64.5%,其中50%的母树结实量在50~100个,结实量在100~200个的占16.1%, 200个以上的占19.4%。200个以上球果的个体均生长在低海拔区间,高海拔处结实量多在100个以下。方差分析表明,两个海拔高度间球果和种子特征差异是显著的,绝大部分球果和种子性状指标的平均值在低海拔处大于高海拔处。因此,从结实特性以及球果和种子的特征来看,低海拔处秦岭冷杉生殖生长好于高海拔处。  相似文献   

7.
利用国内8个省21个居群的车前(Plantago asiatica)种子,测量其在15℃,15%平衡相对湿度下的重量;通过25/10℃下的萌发实验,统计了种子的萌发率及腐烂率,并通过未萌发新鲜种子的比例对种子可能的休眠程度做出估计.收集采集地的地理及气象信息,对车前种子重量、萌发率、腐烂率及休眠率与地理及气象因子之间的关系做双变量相关分析.结果表明,车前50粒种子的重量在0.0047 ~0.0408g之间,平均值为0.0156 g;种子重量与分布区降水量呈极显著的正相关性,同时温度与种子重量也有显著的正相关性;随着温度升高与降水增多,种子重量呈增大的趋势.腐烂率与海拔呈极显著的负相关性,而与经度、年均温及降水量呈极显著的正相关性;休眠率与年均温及降水量分别呈显著或极显著的正相关性.随着海拔升高、经度减少,温度及降水量下降,车前种子的腐烂率呈下降趋势,休眠程度也逐渐降低;因此西部高海拔地区分布的车前种子具有较浅的休眠及较高的库存活力,因而萌发率较高.车前种子在重量、休眠及萌发习性方面的多样性是其对不同环境适应的一种表现.  相似文献   

8.
温度、土壤水分和NaCl对黄顶菊种子萌发的影响   总被引:2,自引:0,他引:2  
光照和黑暗条件下的黄顶菊种子萌发无显著差异;种子萌发的适宜温度为25—35℃;种子萌发率随着NaCl浓度的升高而下降;种子萌发的最佳土壤含水量为35%-45%。在最适温度下,种子萌发耐受NaCl的临界值为89.919mmol·L^-1极限值为218.92mmol·L^-1;不同温度和NaCl以及二者共同作用使黄顶菊种子萌发受到的抑制都极显著。  相似文献   

9.
以中华蚊母树(Distylium chinense)种子为材料,分别设置4个贮藏时间(0、30、60和90d),以及2m水淹(FSW)、低温沙藏(CSS)、低温干藏(CDS)、室温沙藏(RSS)、室温干藏(RDS)和低温层积(CSF)6个贮藏方式对种子进行贮藏实验,并测定分析各处理种子的萌发特性及其幼苗生长状况,明确不同储藏方式和时间对中华蚊母树种子萌发及幼苗生长的影响。结果表明:(1)CSF处理30d后,中华蚊母树的种子有65.37%发生霉烂,最后萌发种子数为贮藏种子的30.93%;FSW处理90d的种子的萌发率为35.67%。(2)室内贮藏90d后,CSS、CDS、RSS和RDS处理的种子萌发率较新鲜种子萌发率(26.37%)显著增大,并以4℃下CDS处理90d的种子萌发率最大(70.65%),萌发速率系数为1 956.97。(3)CDS处理90d的种子淀粉和蛋白质含量较新鲜种子分别降低了38.75%和20.16%,而可溶性糖含量增加了31.47%;FSW处理后的种子淀粉、蛋白质及可溶性糖含量均较新鲜种子显著降低,降幅分别为48.75%、62.62%和6.29%。(4)不同贮藏方式贮藏90d后,各处理间中华蚊母树幼苗的生长活力表现出显著差异,并以CDS处理的幼苗活力最高,而FSW处理的种子萌发后幼苗的活力显著低于其他贮藏方式。研究表明,低温条件下中华蚊母树种子萌发率及幼苗活力显著高于室温贮藏,可能是在低温贮藏条件下种子的贮藏物质由淀粉水解为可溶性糖,更利于种子吸收并为种子萌发提供了能量,从而加快了破除种子生理休眠的进程,而且中华蚊母树种子对水淹有一定的耐受性,故中华蚊母树可以作为三峡水库消落带高海拔区域植被恢复与重建优先考虑的物种。  相似文献   

10.
皂荚天然群体间种实表型特性及种子萌发的差异分析   总被引:1,自引:0,他引:1  
对位于湖北京山、湖南城步、贵州兴义、重庆秀山、四川成都、广西桂林、山东费县和甘肃天水的8个皂荚(Gleditsia sinensis Lam.)天然群体间果实和种子表型特性及种子萌发率的差异进行了研究,在此基础上,对种子特性与萌发率的相关性进行了分析。结果表明:不同皂荚群体间荚果的长度、宽度、厚度和质量以及种子长度、宽度、厚度和百粒质量均存在极显著差异(P〈O.01);在低纬度、高降雨量和干扰程度相对大的区域产生的荚果及种子均较大。在不同温度(昼/夜温度35℃/20℃、30℃/15℃、25℃/10oC和15℃/5℃)条件下,8个皂荚群体间种子萌发率无显著差异,平均萌发率为7.70%;种皮经人为损伤后种子萌发率总体上有所提高且在不同温度条件下差异显著,其中在昼/夜温度15℃/5℃的条件下种子萌发率低于其他处理温度。在不同温度条件下,种子的长度、宽度、厚度和百粒质量与萌发率均呈正相关,但总体上相关性不显著。研究结果说明:不同皂荚群体的荚果和种子特性变异较大,且在降雨量高的地区其果实和种子较大;低温对皂荚种子的萌发有一定抑制作用;种皮损伤处理可解除皂荚种子的物理性休眠,但皂荚种子还可能存在生理休眠现象;一定程度的种子复合休眠可能是皂荚群体适应不同生境的重要生存策略之一。  相似文献   

11.
Seed size is normally distributed for many annual species, while mature plant size is frequently positively skewed. A study was conducted to determine the influence of seed size and the role of genetic differences in determining relative seedling size for Ludwigia leptocarpa. Seed size had a significant effect on percentage germination and time of seed germination but no effect on dry weight or leaf area of seedlings. Seed size and spacing had a significant effect on seedling dry weight for plants grown under competition, while relative day of emergence had no effect. Familial (genetic) differences were found in average seed weight between maternal plants, but not in average number of days to germination, average weight of seeds which germinated, or shoot dry weight. It is concluded that neither seed size alone nor genetic differences between plants are directly responsible for the development of size hierarchies in Ludwigia leptocarpa populations. Large seed size does convey an advantage in growth when plants from seeds of differing initial size interact.  相似文献   

12.
Crisp lettuce plants cv. Saladin were grown from the time they started flowering, at 20/10°C (16 h day, 8 h night), 25/15°C and 30/20°C in glasshouses on two occasions in 1985. Yields of seed increased from, on average, 15 g to 27 g and then fell to 20 g per plant with progressive increases in temperature. The number of mature florets per plant increased with temperature but the number of seeds per mature floret was lower at 20/10°C and 30/20°C than at 25/15°C. An increase in temperature reduced mean seed weight by up to 45%, seed volume by 15%, cell numerical volume density (Nv) by 27% and the number of cells per seed by 39%. Percentage seed germination reached a maximum early in seed development at the stage when the pappus appeared through the involucral bracts. Differences in percentage germination and vigour of seeds (slope test) from different temperatures were accounted for largely by the effects on mean seed weight. However, when germinated at 30°C seeds produced at 30/20°C germinated more readily than those produced at 25/15°C or 20/10°C. Seed vigour gradually increased with an increase in the length of storage after harvest, reaching a maximum after 260 days. In general, seeds produced at 25/15°C exhibited a greater variation in numbers of seeds per floret, Nv, seed weight, times of seedling emergence, seedling and mature head weight than seeds produced at lower or higher temperatures.  相似文献   

13.
Carrot seeds taken from the parent plant were capable of germinating before the stage when maximum seed dry weight was reached but even after this stage, when the seed moisture content had fallen below 20%, improvement in seed germination characteristics continued. In the latter stages of seed growth losses by shedding were 12–20 kg/ha/day. For low density crops (10 plants/m2) the yield of viable seed was at a maximum in crops whose seed was harvested with a moisture content of between 20 and 40% but no consistent relationship could be established for high density crops (80 plants/m2). There were no effects of umbel order or plant density on mean germination time or spread of germination. At any early harvest, percentage germination was highest for primary-umbel-seeds and seeds from low density crops but the differences between the seed origins diminished with later harvests. Drying the seeds on the umbels improved the percentage germination, reduced the mean germination time and the spread of germination particularly at the early harvests compared with seeds removed from the umbels and germinated immediately without drying.  相似文献   

14.
异子蓬(Borszczowia aralocaspica)为中亚荒漠特有种,在我国仅分布于新疆,其果实具有二型性。对同一生长地2006、2007、2008年异子蓬种子的大小、萌发特性及结实格局进行比较,结果表明:(1)年份和种子类型对种子大小和重量均有显著影响(P<0.05)。(2)2种类型种子具有不同的萌发行为,褐色种子萌发率高(>90%),萌发速度快,而黑色种子萌发率低(2006年的萌发率为31%),萌发速度慢;2种类型种子的萌发指数在不同年际间均差异显著。(3)不同年际间,种子总数、褐色种子数、黑色种子数均具有极显著差异(P<0.001),且随个体的增大黑色种子的比例逐渐减小,褐色种子的比例逐渐增大,并且黑色种子数目均高于褐色种子数目。该研究为深入认识异型种子的生态适应对策提供理论基础。  相似文献   

15.
Variation in seed weight is common within and among plant species, but few studies have attempted to document the pattern of seed weight and germination attributes for aquatic macrophytes at a large scale. This study examined within‐species variation in seed weight and germination attributes and the effects of environmental factors on seed traits of the submerged plant Potamogeton pectinatus in the arid zone of northwest China. Our results showed that the average seed weight was 0.24 g per 100 seeds with a coefficient of variation (CV) of 28.4% among the eight P. pectinatus populations. The total germination fraction of seeds of P. pectinatus was relatively poor, less than 35% in seven P. pectinatus populations, and the lowest germination percentage found was only 2%. There were significant differences in seed weight, time to onset of germination, and total germination fraction among the eight different populations. Hierarchical partitioning analysis showed a strongly positive correlation between seed weight and water temperature and pH. Seed weight and the maternal environmental factors significantly affected both time to initiation of germination and total germination fraction. Our results suggest that (1) seed weight variation in P. pectinatus primarily is the result of temperature variation during fruit development; (2) relatively poor germination fraction suggests that seeds are relatively unimportant in the short‐term survival of populations and that it may be another adaptive trait allowing plants to take place in the right place and at the right time, especially in harsh environment; and (3) variation in seed germination traits should be determined by local environmental and intrinsic factors that interact in a complex fashion.  相似文献   

16.
The importance of seed size and density in determining individual plant performance and plant population dynamics in experimental populations of the halophyte Atriplex triangularis was studied. Two distinct seed morphs—large, light seeds and small, dark seeds—are produced by individual A. triangularis plants. Experimental populations consisting of seed size monocultures (large or small seeds) and seed size mixtures were established at three different densities, and the time of germination, plant size, plant survivorship, and plant fecundity were monitored. Marked variation in time of germination was observed among treatments and between seed sizes, but germination within any given treatment occurred over a five- to ten-day period. Large seeds produced larger plants than small seeds did, and this dichotomy was maintained over the course of the entire experiment. Germination date and seed size interacted such that larger plants grew from seeds which germinated earlier than those which germinated later, regardless of seed size. Germination date had a more pronounced effect than seed size did on plant mortality in high density populations. At high density, large seed monocultures experienced greater mortality than small seed monocultures did, but in seed size mixtures, the mortality was evenly distributed between plants from the two seed sizes. Regardless of density conditions and parentage, large and small seeds were produced in equal proportion by the plants. Total seed production, however, was dramatically affected by plant density, and to a lesser degree by germination date. Although seed size effects alone did not appear to affect directly final plant biomass and fecundity, effects of seed size early in ontogeny may have contributed to differences in fecundity.  相似文献   

17.
Summary Models of the evolution of seed dormancy reveal that dormancy is favoured either when opportunities for establishment vary over time and when there is wide variation in the probability of success, or when the probability of success is limited by frequency dependence. Empirical evidence supporting the temporal heterogeneity hypothesis exists, but there is scant evidence for dormancy being favoured by frequency dependent competition among seedlings. We test the hypothesis that the intensity of between-sib competition should favour a positive relationship between maternal fecundity and seed dormancy. This hypothesis is supported for the rare, vernal pool annual,Pogogyne abramsii: the proportion of dormant offspring was significantly higher among high fecundity mothers than among other mothers. Dormancy inP. abramsii is controlled by the seed coat, a maternal tissue, so delaying germination favours the inclusive fitness of mothers by reducing the potential for competition among siblings. Seed weight and time to first germination varied significantly amongP. abramsii plants and mean seed weight increased linearly with plant biomass. Seed weight and seed number are independently regulated by plant size. Overall, seed weight varied 10-fold and variability in seed weight within mothers was not explained by plant biomass, seed yield or mean seed weight. GerminableP. abramsii seeds were significantly heavier than dormant seeds, and germinable seeds heavier than 0.20 mg germinated more rapidly than those smaller than 0.20 mg.  相似文献   

18.
After 120 yr of burial in moist, well-aerated sand, 23 seeds of Verbascum blattaria and two seeds of a Verbascum sp. germinated and produced normal plants (50% germination for Verbascum). After a 6-wk cold treatment, a single seed of Malva rotundifolia germinated also, producing a normal plant (2% germination). Plants were grown to maturity in a greenhouse, and flowering was induced by exposure to a 6-wk cold treatment. Flowers were artificially pollinated to produce seed of both Verbascum blattaria and Malva rotundifolia. The Verbascum sp. failed to set seed. Collected seeds were subsequently germinated, producing normal plants. F(1) seeds of V. blattaria had a germination of 64%. Seeds (6%) of M. rotundifolia germinated after a cold treatment.  相似文献   

19.
Nuclear genetic, maternal genetic and maternal environmental effects on seed characters were estimated in the California native annual plant Nemophila menziesii using two greenhouse crosses. In one cross, according to a nested mating design, the narrow sense heritability of seed weight was small (3.9%). A subset of full-sib progenies produced in this cross was grown singly and in competition with the introduced grass Bromus diandrus. In a second cross, these plants were used as mothers (dams) and were each mated to the same three sires. Seeds produced by mothers competing with B. diandrus showed a significant reduction in weight, increase in time to germination, and increase in the incidence of dormancy, when compared to seeds from mothers grown singly. Significant sire components were found for time to germination and incidence of dormancy. Maternal genetic variation for seed weight was largely expressed as maternal genotype by maternal environment interaction, and showed no significant maternal genetic main effect. Time to germination and dormant fraction showed a relatively large maternal genetic effect. Evolution of seed characters in N. menziesii is more likely to occur via indirect response to selection among maternal plants than among the seeds themselves. Maternal genotype by maternal environment interaction could potentially contribute to the maintenance of maternal genetic variation in seed weight, but this does not appear likely for dormancy.  相似文献   

20.
Transgenerational interactions between flower color, seed quality, and seedling performance have rarely been investigated. The ecological model, Ipomopsis aggregata, is a great candidate for examining the maternal effects of flower color because it is a mostly scarlet-flowering plant which shows color polymorphism within natural populations. Anthocyanin, the red flavonoid pigment which gives these flowers color, has been shown to act as an ultraviolet (UV) protectant by shielding chloroplasts and acting as an antioxidant. This study was conducted on scarlet- and fuchsia-flowering maternal plants and their seeds from natural populations in Colorado. Dark-flowering (scarlet) maternal plants from these populations had consistently higher foliar anthocyanin content, photosystem efficiency, and chlorophyll content than light-flowering (fuchsia) plants over a 3-year period in the field. Seeds from a subset of these maternal plants were counted, weighed, and germinated in a growth chamber. Photosystem efficiency, vegetative anthocyanin content, chlorophyll content, and biomass were measured on germinated seedlings after the germination census was completed. Dark-flowering maternal plants yielded seeds and seedlings with higher biomass than light-flowering ones. Seeds from dark-flowering maternal plants also germinated faster than those from light-flowering maternal plants and seedlings had higher vegetative anthocyanin content. The hereditary nature of anthocyanin content thus suggests that higher anthocyanin levels (both floral and vegetative) are potentially linked to measures of fitness such as increased seed weight, germination rate, and seedling biomass. These data suggest that UV protection provided by anthocyanins potentially increases the realized fitness of maternal plants, thereby influencing life history.  相似文献   

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