993 resultados para seed mass
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After the excavation of Jinping underground cavern, a strong expansion appears along the unloading direction of the rock mass, mainly in the type of tensile rupture, accompanied by shear destruction, unloading resulted in significant deterioration of mechanical properties of rock. Based on the in-site investigation of rock mass structure, via analyzing the acoustic testing data, we identify the unloading range of the side walls and the division of rock types, and carry out with the solution of rock mechanical parameters about different unloading zone, providing geological foundation for the supporting design of the following design of the side walls, at the same time, providing reference for the selection of mechanical parameters of other underground excavation engineering with similar geological conditions.
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繁殖更新是植物生活史的重要阶段,在退化生态系统中,植物繁殖更新能力往往较差,是植被恢复的限制环节,因而也成为恢复研究重点和核心。本研究选择岷江干旱河谷广泛分布的三种蔷薇:多苞蔷薇(R. multibracteata)、黄蔷薇(R. hugonis)和川滇蔷薇(R. soulieana)为研究对象,通过野外调查,在查明其生长、繁殖更新状况的基础上,采用控制和模拟实验,对种子和幼苗阶段进行了深入研究,综合分析更新潜力,并提出相对应的促进更新和植被恢复措施。主要结论如下: 1)三种蔷薇在岷江干旱河谷广泛分布,生长和繁殖状况良好,结实量大。各生长指标:株高、基径和冠幅,繁殖指标:结实数量、重量和单果重量都具有显著的空间差异性。基径对多苞蔷薇结实量影响最大;而冠幅对黄蔷薇结实量影响最大。海拔和纬度是对蔷薇生长和繁殖影响最大的环境因素,随着海拔和纬度的升高,植株生长更高大,结实量增加;坡度和坡向对其生长和繁殖也有一定影响,随着坡度 和坡向增加,蔷薇生长和结实受到抑制。 2)三种蔷薇在岷江干旱河谷更新现状不佳, 但更新潜力大。活力种子比率低,动物取食以及两年生幼苗的大量死亡是蔷薇更新的主要限制因素。多苞蔷薇和黄蔷薇的结实率低,川滇蔷薇较高。三种蔷薇种子产量大,但种子质量较差,更新具有充足的种源。三种蔷薇都能形成持久种子库,种子库中种子总量大,但有效种子少,黄蔷薇被动物啃食的比例很高,多苞蔷薇和川滇蔷薇也有一部分种子受到动物破坏。三种蔷薇幼苗库组成特征表现为,当年生幼苗所占比例很高,年龄较大幼苗所占比例小。 3)三种蔷薇都具有不同程度休眠,未经处理种子的发芽率极低。黄蔷薇休眠程度最深,为深度生理休眠;多苞蔷薇为中度生理休眠;川滇蔷薇为非深度生理休眠。三种蔷薇种子在形态上发育成熟,种皮具有透水性。蔷薇果果肉和瘦果中含有抑制物质,其浸泡液抑制了油菜种子萌发,果肉抑制作用更强,果肉和瘦果浸泡液的抑制程度分别为:川滇蔷薇>黄蔷薇>多苞蔷薇。切割和硫酸腐蚀提高了川滇蔷薇种子的发芽能力,而对多苞蔷薇和黄蔷薇没有影响。完全去除瘦果果皮和种皮提高了多苞蔷薇种子发芽率,但对黄蔷薇没有影响。赤霉素和烟水对蔷薇种子萌发没有促进作用。三种蔷薇打破休眠所需低温层积时间分别为:黄蔷薇>多苞蔷薇>川滇蔷薇。对于多苞蔷薇和川滇蔷薇,层积前对种子进行硫酸腐蚀或暖温层积能缩短低温层积时间,提高发芽率。对于多苞蔷薇,变温层积中暖温层积和低温层积具有一定的负补性,即延长暖温层积可以缩短种子萌发对低温层积的需要。 4)多苞蔷薇种子形态特征和种子休眠与萌发在不同海拔梯度间存在较大差异。种子采集时间、采集季节和干藏影响多苞蔷薇和川滇蔷薇的种子休眠。多苞蔷薇果实大小、种子大小和千粒重、种皮厚度随海拔升高而增加,而种子饱满率和活力随海拔升高而降低,种子休眠程度也随海拔升高而增加。种皮厚度与种子大小、千粒重成正相关关系,硫酸腐蚀后的种子经过不同时间的低温层积后,种子发芽率与种皮厚度、种子大小、千粒重、海拔成正相关关系。2006 年采集川滇蔷薇和多苞蔷薇种子休眠程度较2005 年低。种子休眠随种子年龄增加而减弱。高温和干旱能减轻多苞蔷薇和川滇蔷薇种子休眠。 5)三种蔷薇的生长和生物量积累在干旱胁迫条件下受到抑制,而生物量分配、叶片形态特征和水分利用特征等都发生了变化。三种蔷薇的根、茎、叶各器官生物量以及总生物量等在干旱胁迫下明显减小,叶片脱落数量增加。在干旱胁迫条件下,较多的生物量分配到地下部分,从而这使R/S 明显增加。比叶面积(SLA)和冠层面积比(LAR)对干旱胁迫的反应不敏感,仅有部分物种在干旱胁迫条件下发生了变化,并且其变化特点在不同年龄幼苗之间有一定差异。干旱胁迫对WUE 的影响在不同物种间存在差异。多苞蔷薇和黄蔷薇的WUE 随着干旱胁迫的增加而增大, 而川滇蔷薇的WUE 则随干旱胁迫增加而减小。在干旱胁迫条件下,多苞蔷薇和黄蔷薇叶片脱落量和生物量减小幅度较川滇蔷薇大,表明其抗旱能力较强。在干旱胁迫条件,三种蔷薇两年生幼苗的生物量减小幅度较当年生幼苗小,表明两年生幼苗的抗旱能力更强。 6)两种植被恢复措施中,幼苗移栽比播种具有更好的植被恢复效果。播种后,蔷薇种子的发芽率较高,但出苗率都很低,即使出苗,幼苗也几乎在一月内全部死亡。 三种微生境条件下(灌木、半灌木和裸地),种子出苗和幼苗成活没有差异。移栽幼苗总体死亡率都比较低,小于20%。特别是两年生幼苗死亡率更低,小于2%。移栽后的幼苗生长状况良好,在整个生长季中,各生长指标不断增加。生境对幼苗的存活率没有显著影响,但对于幼苗的生长和生物量积累有一定影响,裸地更有利于幼苗生长和生物量积累。与当年生幼苗相比,两年生幼苗具有更高的成活率。总之,三种蔷薇在干旱河谷分布广泛、生长繁殖状况良好,结实量大,具有丰富种源,繁殖更新潜力大,但繁殖更新状况不佳;种子散布后动物对种子的取食、种子的深度休眠过程、种子出苗以及当年生幼苗的存活和定居是更新的主要限制环节。水分是影响结实、种子休眠解除和萌发,幼苗存活和定居的最主要的限制因素。在植被恢复中,应在种子成熟季节大量采集种子,在室内打破休眠后进行人工播种,培育两年生幼苗,通过幼苗移栽方式进行植被恢复。川滇蔷薇应栽种在相对湿润的过渡区,而多苞蔷薇和黄蔷薇可以应用于核心区植被恢复。 Regeneration is an important phase in plant life cycle. It has been a key component of ecological restoration in degradation ecosystem in which plants commonly has poor regeneration. In this paper, we investigated the natural growth, propagation and regeneration status of native three rose species, Rosa multibracteata, R. hugonis and R. soulieana, and analysis the limitation in seed germination and seedling establishment stages. Advice on facilitating the use of these plants in restoration based on the results has been proposed. The results were as follows: 1) Three rose plants widely distributed in the dry valley of the Minjiang River, and made a good performance in growth and propagation. There were significant spatial differences in each growth parameter, such as ramet height, basal diameter, crown diameter and propagation parameters including hip number of a clump, hip mass of a clump and a hip mass. Basa diameter was the most important growth parameter influencing fruit number for R. multibracteata and crown diameter was for R. hugoni. Altitude and latitude had the greatest effect on the growth and propagation of rose plants among environmental conditions. Each parameter of growth and propagation increased with the increase of altitude and latitude. In addition, the increase of slope and aspect limited the growth and propagation. 2) Three rose plants had poor natural regeneration, but great regeneration potential. Low seed viability, predation and higher mortality of current year old seedlings were the limitation in regeneration. R. multibracteata and R. hugonis had higher fruiting rates than R. souliean. All three plants produced a great number of seeds, while their viability was poor. Three rose plants had persistent seed banks, with high total seed number but very low viable seed density. Predation was most severe in R. hugonis, and it also existed to some degree in R. multibracteata and R. soulieana. The seedling age-structure was characteristic of current-year seedlings predominating and few older seedlings were observed. 3) Three rose seeds were dormant and untreated seeds germinated with very low germination percentages. The rose seeds had morphological mature embryos, and achenes were permeable. Some inhabit substances existed in hips and achenes for the extracts of hips and achenes inhibited germination of Brassica campestris. The inhibition effect of the extracts of three rose hip and achenes was R. soulieana>R. hugonis>R. multibracteata. Mechanical and H2SO4 scarification increased R. soulieana germination but had no effect on germination of R. hugonis and R. multibracteata seeds. Full removal of pericarp and testa improved the germination of R. multibracteata but did not affect R. hugonis germination. GA3 and smoke water had no positive effect on rose seed germination. The periods of cold stratification required to released seed dormancy was R. hugonis > R. soulieana >R. multibracteata. H2SO4 scarification and warm stratification shortened cold stratification to release dormancy for R. soulieana and R. multibracteata. Warm stratification had complementary effect for cold stratification, i.e. the longer warm stratification seeds received, the shorter cold stratification were required to obtain the same germination percentage. Three rose seeds had different kinds of dormancy; R. hugonis has deep physiological dormancy, R. multibracteata with intermediate physiological dormancy and R. souliean non-deep physiological dormancy. 4)The seeds traits and dormancy of R. multibracteata showed significant difference across altitudes. Year and season of seed collection had significant effect on seed dormancy for both R. souliean and R. multibracteata. Hip size, seed size, seed weight, seed coat thickness and seed dormancy level increased with the increase of the altitude. There were positive relations between seed coat thickness with seed size and seed weight. Germination percentage of seeds treated with H2SO4 scarification following different periods of cold stratification showed positive relation with seed coat thickness, seed size, seed weight and altitude. Seeds of R. souliean and R. multibracteata collected in 2006 had low dormancy level than those collected in 2005. Seed dormancy decreased with increasing seeds age. High temperature and drought were associated with low dormancy level. 5) Seedling growth, the total dry mass and their components of seedlings were reduced, while leaf senescence accelerated under drought stress. More biomass allocation to root system resulted in higher R/S ratio under drought. Water-use efficiency (WUE) of R. multibracteata and R. hugonis increased, while it declined for R. soulieana under drought stress. R. soulieana seedlings had poor drought-resistance capacity it had more senescent leaves, and its reduction of biomass was stronger than two other rose plants under drought. The reduction degree of one year old seedlings under drought stress was slighter than that of current year seedlings. Therefore, one year old seedling was more drought-resistent compared to current year seedlings. 6)Planting seedlings may have better effect in comparison with direct seeding. Most seeds germinated after seeding, but seedling emergence was very low. More than 80 % seedlings from direct seeding died within a months after emergence. Seedling emergence and survival rate did not show difference among microhabitats. Mortality rates of seedlings artificially planted in microhabitats were general lower than 20 %, and the mortality rate of one year old seedlings was lower than 2 %. Each grow parameter including plant height, leaf number and branch number continually increased after planting. Microhabitat type had effect on the growth parameter and biomass production, but it did not influence the seedling survival. Bare land tended to facilitate seedling growth. One year old seedlings had higher survival rate than current year seedlings. In conculsion, the three rose had wide distribution in the dry valley of the Minjiang River. They produced many seeds and had tolerance to drought stress to some degree. But they had poor regeneration in habitats may be caused by predation, seed dormancy,and high mortality in current year seedlings. We recommend that rose plants should be utilized in restoration by planting two-year old seedlings in spring. A large quantity of seeds should be collected artificially in autumn, release seed dormancy in room, and then cultivate two-year old seedlings by seeding in particular container. R. soulieana seedling probably be planted in transition area, and R. multibracteata and R. hugonis can be used in core area of the dry valley of the Minjiang River.
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植物功能生态学研究不仅提供了植物生理生态学与生态系统生态学的连接,还为植物种群生活史对策研究提供了材料。Westoby 等 (2002) 提出了利用植物功能性状变量的主导维度来确定和量化植物生活史的生态适应策略。在他们所提出四个主导维度中,叶大小-小枝大小是研究相对较少的一维;其内部各组分的关系、对环境的响应,以及与其它重要维度的关系,目前的理解非常有限。 本研究以贡嘎山不同海拔不同功能群物种为研究对象,采用种间比较和系统发生独立性比较等研究方法,系统研究了植物的功能特征及其相关性在不同生境及不同功能群间的差异,旨在分析不同功能群物种的叶大小-小枝大小的成本和收益。其研究结果将有助于我们理解植物生活史对策的进化,进而理解物种共存和维持物种多样性的机制。主要研究结果如下: 1. 叶大小-小枝大小关系 小枝茎横截面积与单叶面积和总叶面积均呈异速生长关系,即总叶面积和单叶面积的增加比茎横截面积的增加速度快。但是,总叶面积和叶片干重的增加却基本上与小枝茎干重的增加等速。系统发生独立性比较研究的结果与此相一致。表明,在某一给定的茎投入时,至少大叶大枝物种不比小叶小枝物种在支撑叶面积和叶片干重方面具有优势。同时,在某一给定的小枝茎投入时,常绿阔叶物种比落叶阔叶物种支撑更少的叶面积。在茎干重与总叶面积的关系中,落叶复叶物种比落叶单叶物种具有更高的y轴截距,表明复叶物种比单叶物种在展叶面积方面更有效。复叶物种与单叶物种相比,通常具有较大的叶大小和小枝大小。 2. 叶大小-叶数量关系 叶大小与数量间在不同的叶片习性、不同的叶片形态以及不同的生境类型的物种间均存在稳定的负的等速生长关系,且这种关系在系统发生独立性比较时依然成立。然而,在某一给定的出叶强度 (单位小枝的叶数量) 时,常绿阔叶物种比落叶物种具有更小的叶面积。而在给定体积基础上的出叶强度时,落叶复叶物种的叶面积显著大于落叶单叶物种,且复叶物种比单叶物种具有更大的叶大小和更小的出叶强度。但是,叶大小与数量间的关系在不同的海拔间并没有显著的差异。 3. 小枝大小-总叶面积关系 在不同的生活型或不同的生境下,小枝上总叶面积与茎干重和小枝干重均呈正的异速生长关系,且斜率显著小于1.0,表明小枝上总叶面积的增加都不能赶上小枝及茎大小的增加。这种“收益递减”表明随着小枝干重的增加,光截取的收益递减。此外,叶面积比 (总叶面积与小枝干重的比值) 与单叶干重呈显著负相关关系,系统发生独立性比较的结果与此相一致。根据以上结果,可以推测,大叶的物种在质量较好的生境中出现,而群落内部小枝茎的寿命较长的物种可以拥有较大的叶片。 4. 叶片色素浓度-LMA关系 随着海拔的升高,阔叶木本植物和草本植物的叶片色素浓度减少,叶绿素a/b和类胡萝卜素/叶绿素比值以及比叶重 (LMA) 增加。然而,在草本植物中的色素浓度、色素比值和LMA的变化比阔叶木本植物的更明显。同时,LMA与叶片色素浓度呈负相关关系,但是在落叶物种中的LMA对色素浓度的影响比常绿阔叶物种更强烈。总之,草本植物的叶片特征对海拔梯度的变化似乎比木本植物更敏感,LMA对叶片色素的保护作用在落叶物种中比在常绿阔叶物种显得更重要。这些结果表明不同生活型物种可能采取不同的保护机制来降低叶绿体器官的损伤和增加他们的碳获取能力。 Studies on plant functional ecology not only bridge plant eco-physiology and ecosystem functioning, but also enrich plant population biology. As pointed out by Westoby et al (2002), plant life history strategies can be identified and quantified by four leading dimensions of variations in plant functional traits, i.e., seed size/output, leaf mass per area and leaf life span, plant height, and leaf size-twig size. Compared to the other dimensions, the cost/benefit of the leaf size-twig size spectrum has scarcely been analyzed in relation to environmental gradients and life form types, and the adaptive significance of this spectrum is not fully understood. In the present study, the relationships between functional traits of plant twigs are determined for the species with different life forms along an altitudinal gradient of Gongga Mountain with both cross-species analysis and evolutionary divergence analysis. The primary objective of this study is to examine the cost/benefit of leaf size-twig size in plants. The study results are supposed to provide insights into the understanding of the mechanism of species coexistences. The results are shown in the following. 1. The relationship between leaf size and twig size Twig cross-sectional area allometrically scaled with both individual leaf area and total leaf area supported by the twigs. However, the increase in total lamina mass/area was generally proportional to the increase in stem mass. These correlations between trait variations were significant in both interspecies analysis and phylogenetically independent comparison (PIC) analysis, which indicated that thick-twigged/large-leaved species, at least, do not have an advantage in supporting leaf/lamina area and lamina mass for the same twig stem investment than thin-twigged/ small-leaved species. Meanwhile, the evergreen broad-leaved species supported a smaller leaf area for the same twig stem investment in terms of both cross-sectional area and stem mass than the deciduous species. The deciduous compound-leaved species have a higher y-intercept in the scaling relationship of twig stem mass versus total leaf area than the deciduous simple-leaved species, indicating that compound-leaved species were more efficient in displaying leaf area. The compound-leaved species were larger in both leaf size and twig size than their counterpart in the present study. 2. The relationship between leaf size and leaf number Significantly negative and isometric scaling relationships between leaf size and leafing intensity (leaf number per twig mass or volume) were found to be consistently conserved across species independent of leaf habit, leaf form and habitat type. The negative correlations between leaf size and leafing intensity were also observed across correlated evolutionary divergences. However, leaf area was smaller in the evergreen broad-leaved species at a given leafing intensity than in the deciduous species. The deciduous compound-leaved deciduous species were higher in leaf area than deciduous simple-laved species at a given volume-based leafing intensity. Moreover, the compound-leaved deciduous species were larger in leaf size but smaller in leafing intensity than their simple counterparts. No significant difference was found in the scaling relationships between altitudes. 3. The relationship between twig size and total leaf area Leaf area was found to scale positively and allometrically with both stem and twig mass (stem mass plus leaf mass) with slopes significantly smaller than 1.0, independent of life form and habitat type, indicating that the increase in total leaf area fails to keep pace with increasing twig size and stem size. This ‘diminishing returns’ suggests that the benefit of light intercept decreased with increasing twig mass. Moreover, the leaf area ratio (the ratio of total leaf area to stem or twig mass) correlated negatively with individual leaf mass. The results of PIC were consistent with the correlations. According to the results, it is speculated that large-leaved species may be favored when habitat is good and when stem longevity are long within community. 4. The relationship between leaf pigment concentrations and leaf mass per area With increasing altitude, the concentrations of pigments decreased, but the ratios of chlorophyll a/b and carotenoid/chlorophyll, and LMA increased, in both the broad-leaved woody species and herbaceous species groups. However, the changes in the pigment concentrations, ratios and LMA were more profound in the herbaceous species than in the woody species. In addition, pigment concentrations were negatively correlated with LMA in each life form type and in the pooled dataset. However, the LMA effect on leaf pigment concentrations was more profound in the deciduous species than in the evergreen braode-leaved species. In general, herbaceous species seemed more sensitive to the increasing altitude compared to woody species, and LMA seemed to be a more important mechanism for protecting leaf pigments in deciduous species than in evergreen broad-leaved species. These results suggested that the species with different life forms may employ different protective mechanisms to decrease the chloroplast apparatus damage and increase their carbon gain.
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本文主要研究了具有己酸乙酯酯化活性的真菌菌株的筛选和发酵条件优化。从大曲和糟醅样品中分离纯化获得79株产生透明圈的丝状真菌,菌落形态初步识别结果显示分离菌株包括红曲霉属、根霉属及曲霉属等菌株。其中菌株EM-56酯化酶活力最强,发酵获得的粗酶制剂酶活为172.36 u。根据显微形态、菌落形态及生理生化特征,初步鉴定该菌株为曲霉科红曲霉属紫色红曲霉(Monascus purpureus)。 在此基础上重点研究了菌株EM-56在不同培养基成分及不同培养条件下的产酶情况,确定了最佳培养基和培养条件。通过单因素实验确定在基础培养基中添加最佳碳源为葡萄糖,最佳氮源为蛋白胨。正交优化实验结果确定了最佳培养基组成:以麸皮为基础培养基,添加葡萄糖 2%,蛋白胨 0.3 %,KH2PO4.3H2O 0.05 %,MgSO4.7H2O 0.06 %。菌株EM-56在上述培养基中的最佳发酵条件为:初始pH 5.5,发酵温度为35°C,发酵时间7d,种龄48h,接种量8%,装瓶量50g / 瓶(500mL)。在最佳培养基和发酵条件下,菌株EM-56发酵获得的粗酶制剂酶活达到241.56 u,比优化前提高了40.15%。 In this paper, the research focuses on the selection of fungus with esterifying activity and optimization of fermentation conditions. We isolated 79 strains which had transparent zones from Daqu and fermented grains. The isolated strains contained Monascus、Rhizopus and Aspergillus through primary morphology analysis. The strain of EM-56 which produces strongest esterase was selected. The enzyme activity reached 172.36u. According to related literature, EM-56 was identified as Monascus purpureus through morphology analysis and biochemical determination. We also studied the effects of different medium and fermentation conditions on the esterase production of strain EM-56. The optimal medium and fermentation conditions were determined. Single factor experiment result shows that the optimal carbon source added is glucose and the optimal nitrogen source added is peptone. The optimal fermentation medium determined by orthogonal optimization test is as follows: wheat bran as substrate, glucose 2%, peptone 0.3%, KH2PO4.3H2O 0.05%,MgSO4.7H2O 0.06%. The optimal fermentation conditions are: initial pH 5.5, cultural temperature 35°C, cultural time 7d, seed age 48h, inoculation 8%, medium mass 50g / flask(500mL). The esterse activity of EM-56 cultivated in the optimal medium and fermentation conditions reached 241.56u and increased by 40.15% compared with the original activity.