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固定沙丘生物结皮层藓类植物形态结构及其适应性研究 总被引：16，自引：6，他引：10
对腾格里沙漠沙坡头地区及其毗邻区域固定沙丘生物土壤结皮层6种有代表性藓类植物形态解剖结构及其适应性进行了观察和系统分析,结果表明:优势种真藓、土生对齿藓和刺叶赤藓植物体密集丛生,其中真藓和土生对齿藓易于通过茎叶碎片或芽胞进行无性繁殖,其茎的结构中皮部细胞壁明显增厚、中轴分化明显;刺叶赤藓和芦荟藓叶片结构最复杂,刺叶赤藓叶片具两层细胞,细胞密被透明马蹄形细疣,芦荟藓叶片内卷成兜形,中肋扁宽,背部有多层厚壁细胞,腹部着生许多绿色丝体;绿色流苏藓和盐土藓的叶片细胞也发生了明显的分化。藓类植物多样的形态结构特征使其适应沙漠环境中水分缺乏、基质不稳、强光辐射伤害等不利环境因子。植物体集群生长状态是其形态适应性的重要特征,与繁殖过程中植物体的连续分枝和原丝体反复再生及外延生长特性直接相关,个体和种群形态结构上的适应性对减缓细胞内生理条件的剧烈变化,减弱细胞器受损害的程度,加快其生理功能的恢复速度有重要作用。 相似文献
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荒漠藓类结皮层中齿肋赤藓形态结构适应性及其原丝体发育特征 总被引：3，自引：1，他引：2
在实验室内通过光镜与扫描电镜相结合的手段观察了新疆古尔班通古特沙漠藓类结皮层的优势物种——齿肋赤藓(Syntrichia caninervis Mitt.)的形态结构特征及其原丝体发育的全过程,并分别从藓类植物生长发育所必经的配子体和原丝体两个阶段对齿肋赤藓形态结构与荒漠干旱的生态环境之间的适应性关系进行了探讨。研究结果表明,①植物体密集丛生;叶片边缘强烈背卷,两面均具马蹄形细疣;中肋粗壮并突出叶尖成白色长毛尖。②原丝体系统的细胞短粗,细胞质高度浓缩,液泡较小,细胞壁较厚;原丝体系统具有短枝群。 相似文献
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2006年开始在库布齐沙漠选择4种藓类植物进行人工培养促进结皮层形成实验,发现人工结皮层中藓类成活率、盖度与土壤基质、降雨量、小生境和藓类植物的生长和繁殖特性密切相关。双色真藓（Bryum dichotomum）成活率和盖度最高,密度与盖度相关,可形成大面积藓类结皮层。单位面积内土生对齿藓（Didymodon vinealis）密度最大,对结皮层的稳定具有重要作用。在培养初期藓类植物生长和繁殖速度较快的原因是消耗繁殖体内营养的结果,以后稳定在一个水平上不会出现生长的高峰期。本项研究为人工培养藓类植物促进结皮层的形成提供了实验依据,并为深入探讨生物结皮层的形成和维持机制提供基础科学资料。 相似文献
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荒漠藓类植物是典型的变水植物,对水分能够快速做出反应,恢复光合、呼吸等生理活性,且荒漠藓类植物对水分的敏感性显著高于维管束植物。藓类植物的生态化学计量特征易受到微环境影响,对于藓类植物生态化学计量特征是否受荒漠降水梯度的影响并不清楚。为深入了解荒漠藓类结皮氮（N）、磷（P）化学计量特征对荒漠年降水的响应特征,以齿肋赤藓（Syntrichia caninervis）作为研究对象,测定3个年降水量下齿肋赤藓植物地上、地下部分N、P元素含量,分析不同降水梯度下齿肋赤藓植物N、P元素化学计量特征。结果表明：（1）齿肋赤藓植物地上部分N、P含量显著高于地下部分,地下部分N、P元素的变异系数比地上部分高,齿肋赤藓植物地上部分氮磷比（N∶P）值为10.17～12.03,生长可能受到氮限制;（2）随年降水量的增加,齿肋赤藓植物地上部分N、P含量呈下降趋势,N∶P比均呈升高趋势;（3）齿肋赤藓植物N、P含量显著正相关,且随年降水量的增加,齿肋赤藓植物地上、地下部分的N-P幂关系指数无显著变化。古尔班通古特沙漠齿肋赤藓植物在N、P养分分配上具有较高的稳定性,且能够通过调节地上与地下部分N、P元素化学计量特... 相似文献
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沙坡头固定沙丘结皮层藓类植物繁殖生物学特性研究 总被引：10，自引：6，他引：10
采用撒茎法和芽胞培养土生对齿藓Didymodon vinealis的实验表明:芽胞由植物体叶腋腋毛顶端细胞反复再生,原丝体由芽胞和叶基部细胞产生或由腋毛直接生长为原丝体,附着在叶背面的芽胞比未附着芽胞产生的原丝体生长更好;老茎不直接生长为植物体,产生新生枝后死去.同时,实验室培养的真藓Bryum argenteum其植物体、叶和细胞形态特征与野生种有明显差异.为人工促进固定沙丘结皮层的形成提供理论和实验依据. 相似文献
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毛乌素沙地生物结皮层藓类植物培育试验研究 总被引：5，自引：1，他引：4
通过对毛乌素沙地不同发育程度的藓结皮进行养分分析,根据其N、P、K含量,对Knop培养液进行修正,按照正交试验设计方法进行室内培育实验,研究最适合毛乌素沙地藓类植株茎叶碎段生长发育的温度、培养液浓度以及培养液使用量。结果表明,当温度为15 ℃,培养液为low Knop,加液体量为12 ml时,藓结皮的生长发育状况良好,其株密度为329株·皿-1,平均株高为4.5 mm; 25 ℃时处理间差异不显著,生长情况不及15 ℃,而35 ℃高温下没有茎叶碎段生长繁殖。根据所有处理株高随时间的变化,得出了藓类植株生长拟合曲线。本实验可为野外培育藓结皮尤其是毛乌素沙地生物结皮的人工修复提供了一定的参考。 相似文献
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以长白山区泥炭地的6种泥炭藓孢子和8种维管植物种子为受试材料,进行室内模拟实验,对比研究了沙尘沉降对泥炭藓孢子和维管植物种子萌发的影响。数据分析显示,施加沙尘抑制除锈色泥炭藓外其他所有泥炭藓孢子的萌发,在接近自然沉降的50 g/(m2·a)水平时,这些泥炭藓孢子的萌发率均下降一半以上。无论沙尘施加量如何,有4种维管植物种子均未萌发。施加沙尘抑制了狭叶杜香（Rhododendron tomentosum）和小白花地榆（Sanguisorba parviflora）种子的萌发,但却对宽叶杜香（Rhododendron palustre）和燕子花（Iris laevigata）种子的萌发呈现一定的促进趋势。研究表明,沙尘沉降可抑制泥炭地泥炭藓孢子和部分典型维管植物种子的萌发,但可能会对非典型的或喜营养的泥炭地维管植物种子萌发产生促进作用。所以,长期存在的沙尘沉降,可能通过提高泥炭地N、Ca水平和pH值的作用,抑制泥炭藓孢子定居,阻滞中国长白山区泥炭地自发演替的进程。 相似文献
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《中国沙漠》2017,(1)
以腾格里沙漠东南缘人工固沙植被区藓类结皮优势种真藓(Bryum argenteum)和土生对齿藓(Didymodon vinealis)为研究对象,在野外条件下设置4个降雪处理,分别是无降雪(对照)、1/2降雪、1倍降雪、2倍降雪,降雪后测定植株光合色素含量、脯氨酸含量、可溶性糖含量、可溶性蛋白含量以及丙二醛(MDA)含量,研究结皮层2种藓类植物对降雪的生理生态响应及其差异性。结果表明:随降雪量增加,真藓和土生对齿藓光合色素含量和可溶性蛋白含量均升高,且土生对齿藓含量上升趋势更明显;随降雪量增加,2物种脯氨酸含量、可溶性糖含量及丙二醛(MDA)含量均降低,且土生对齿藓可溶性糖含量与MDA含量下降趋势更明显。冬季降雪能够对结皮层藓类植物光合作用和生理活性起到一定促进作用;土生对齿藓对降雪的响应更明显。降雪量增加可能会改变藓类结皮层物种组成和结构,并对维持荒漠生态系统健康产生重要影响。 相似文献
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UV-B辐射对生物结皮层藓类植物生理生化指标的影响 总被引：1，自引：0，他引：1
以腾格里沙漠东南缘人工固沙植被区常见藓类结皮中的真藓(Bryum argenteum)和土生对齿藓(Didymodon vinealis)为研究对象,通过室内模拟沙坡头地区臭氧损耗0%(对照)、6%、9%和12%所达到的UV-B强度梯度(2.75、3.08、3.25、3.41 W·m-2),研究了增强UV-B辐射对两种藓类植物渗透调节物质、膜质过氧化程度及抗氧化酶活性的影响。结果表明:随着UV-B辐射增加,两种藓类植物丙二醛(MDA)含量显著升高;可溶性糖含量、超氧化物歧化酶(SOD)及过氧化氢酶(CAT)活性则降低;且UV-B辐射对真藓的影响大于土生对齿藓,说明真藓对UV-B辐射相对更敏感。本研究结果也预示着在未来UV-B辐射增强的情况下,温带荒漠生物土壤结皮(BSC)的组成和结构将会发生显著变化,这种变化将会深刻地影响BSC在荒漠生态系统中的功能,进而影响荒漠生态系统的健康和稳定。 相似文献
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Lloyd R. Stark Brent D. Mishler D.Nicholas McLetchie 《Journal of Arid Environments》1998,40(4):401-416
The low elevation Mojave Desert cryptobiotic crust is dominated by the mossSyntrichia caninervis. In 16 populations of this moss, stem height and population were significantly associated with sex expression, with longer stems expressing sex more frequently and producing more perichaetia. The above-ground age of stems ranged up to 10 years, with a mean growth rate across populations of 0.36 mm year−1. The overall stem sex ratio, as a proportion of the total number of stems, was 0.30♀: 0♂: 0.70 non-expressing. The probability of expressing sex in a given season was 0.09. The absence of sexual reproduction (no sporophytes) and likely absence of the male sex from the area indicate that the non-expressing plants are female individuals. The slow growth rates, low rates of sex expression, absence of male plants, and absence of sexual reproduction in this crustal species may help explain why re-establishment of mosses on desert soils can take decades. 相似文献
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As part of the restoration of degraded land south of the Sahara, an experimental study has been carried out on the germinative properties of the seeds of seven Sahelian leguminous species (Cassia obtusifolia, Cassia occidentalis, Indigofera astragalina, Indigofera senegalensis, Indigofera tinctoria, Sesbania pachycarpa and Tephrosia purpurea). Analysis of the effects of temperature, pretreatment and water potential has enabled definition of their optimum germination conditions. For the temperature range studied (20–40°C), germination capacity was significantly greater between 30 and 35°C for all species. All species except Cassia obtusifolia developed a very strong integumental inhibition which was easily eliminated by mechanical scarification or immersion in concentrated sulphuric acid (H2SO4, 95%). Study of the influence of water potential on germination showed that these species are able to germinate at relatively low water potentials. Different patterns of response to water stress are highlighted and explained by the different behaviours of these species in the semi-arid conditions of the Sahelian environment. 相似文献
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Populations of two ornamental exotic species, Kalanchoe daigremontiana and Stapelia gigantea, have been recently detected inside a protected area containing arid ecosystems in Venezuela. We indirectly tested their invasive potential by characterizing their reproductive biology and recruitment patterns and comparing our estimates against Baker's Law and reproductive profiles reported for invasive plants. K. daigremontiana is autogamous, produces >16,000 seeds per plant and also reproduces clonally. Despite low seed viability (17.9%) and germination rates (11.9%), seeds were present in the seed bank. Plantlets of asexual origin showed high survival (75–100%) compared to seedlings of sexual origin (10%). S. gigantea is self-incompatible, xenogamous and produces close to 1500 seeds per m2 of plant tissue. Seed viability (77%) and germination rates (62%) were high, but this species is not represented in the seed bank. It has a vegetative growth. A combination of reproductive and recruitment attributes, which match those considered in Baker's Law and others reported for invasive plants, confer K. daigremontiana and S. gigantea the potential to invade Neotropical arid zones; the former mainly through selfing and production of numerous asexual plantlets, and the latter through an association with a locally abundant pollinator and production of wind dispersed seeds. 相似文献
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Few studies have determined the importance of orientation on flower reproductive success. Flower orientation may affect reproduction of Cactaceae; the interception of photosynthetic active radiation (PAR) differs along the different sides of cacti stems, and translocation of resources between cacti ribs does not appear to occur. Therefore, PAR received by each cacti stem face may determine the resources available for reproduction. We examined the reproductive success of Pachycereus weberi flowers with contrasting orientations. Ovule production per ovary, number of seeds per fruit, seed set per fruit and seed weight were used as indicators of reproductive success for flowers facing southeast and northeast. PAR received on opposite stem sides was recorded as an estimator of resource availability for each side. Results showed that flowers facing southwards produced more ovules and seeds and produced heavier seeds. Seed set was not significantly different between flowers with contrasting orientations. The southern stem faces received more PAR than the northern faces. Reproductive success was different for flowers with contrasting orientations, suggesting that there is an association between PAR received on different P. weberi stem faces and floral reproductive success. 相似文献