六盘山区山桃种群的实生更新研究

发布时间：2018-06-12 09:14

本文选题：山桃 + 实生更新　；参考：《北方民族大学》2017年硕士论文

【摘要】：山桃(Amygdalus davidiana)是六盘山国家级自然保护区植被恢复、抗旱造林与具有重要观赏价值的树种。本论文在调查了六盘山区山桃林植株的结实率和林下幼苗库数量及年龄组成的基础上,研究了与山桃种群更新相关的种子扩散、种子休眠及其破除方法、种子萌发和幼苗生长的影响因素等环节及其协同关系,并研究了机械性伤害对山桃幼苗萌生能力的影响,研究结果可为山桃种群的天然或人工更新及生态系统管理提供科学依据。主要研究结果如下:1.本研究的山桃种群所在年份处于结实小年;坡位和林冠生境通过影响光照和土壤水分异质性从而影响山桃幼苗生长与存活。山桃种群在2016年结实量(坡底平均为3.44个/株)和结实率(坡底为0.24%)都极低;生境(林冠间隙/林冠下)因素对山桃林幼苗库的密度具有显著影响(P0.01),林冠间隙和林冠下的幼苗密度均在坡底最高,坡顶的林冠间隙和林冠下生境间差异显著(P0.01),其它坡位的不同生境间及不同坡位间均无显著差异;幼苗库中2-3年生和4-5年生幼苗数量占优势,1年生和6年生以上幼苗相对较少。2.土壤覆盖有利于山桃种子的存留;种子特征和啮齿动物的搬运与贮藏的协同作用促进种子扩散。土壤覆盖处理的种子在密度为1枚/m2、4枚/m2、9枚/m2下的留存率均最高,分别为83.33%、41.67%、47.22%;清除凋落物处理种子在相对较低的密度(1枚/m2和4枚/m2)下搬运后的贮藏率较高,分别为16.67%和18.75%;在不同覆盖处理和密度下山桃种子被啮齿动物搬运后取食和贮藏的距离均无显著性差异(P0.05),而搬运后取食的距离均大于搬运后贮藏距离。总体而言,不同覆盖物处理种子被动物搬运后取食和贮藏的距离均为凋落物覆盖清除凋落物土壤覆盖;清除凋落物处理种子被搬运距离的分布频次集中于1-3 m、3-5 m、5-10 m距离组,凋落物覆盖处理种子集中于3-5 m、5-10 m距离组,土壤覆盖处理种子集中于1 m、1-3 m、3-5 m距离组。3.低温层积可有效地打破山桃种子的休眠,从而促进其萌发。山桃种子的最佳层积时间为35 d,而随着层积处理时间的延长,种子萌发参数略有下降;不同大、小山桃种子的萌发率均随着光照强度的降低而减小。山桃大种子在播种深度为0.5 cm和1 cm下所有萌发参数均显著高于小种子(P0.05),而相对较深的播种深度不利于山桃种子萌发。4.光照和水分是影响山桃幼苗生长与存活重要环境因子。山桃幼苗的株高在较强光照(55.4%自然全光照(natural sunlight,NS))下最小(9.9 cm),其与单株叶面积均随着光照的减弱先增大后减小;幼苗基径、叶片数、主根长、侧根数、总干质量和根冠比等生长参数均在55.4%NS或18.9%NS下最大,且随光照的减弱表现出持续减小或波动性减小的趋势;随着光照的减弱,比根长、比枝长和比叶面积均随光照的减弱而增大,在5.5%NS或2.2%NS处理最大。总的来说,光照有利于山桃幼苗的生长和干物质积累,幼苗在不同光强下具有较大的形态学可塑性,表明其对自然分布区生境光照条件具有较强的适应性。在强光与干旱胁迫的综合影响下,山桃幼苗通过降低株高、单株叶面积,增大其根冠比来适应环境,而充足的光照和水分条件则有利于山桃幼苗生物量的积累。在55.4%NS光照强度下,每3 d和7 d浇一次500 ml水的幼苗干质量显著大于其它处理幼苗的(P0.05)。5.不同坡位生境影响山桃幼苗的生长与存活。结果表明:人工移栽幼苗的存活率表现为坡底中坡坡顶;幼苗株高、基径、主根长、叶片数、单株叶面积和总干质量等生长参数均在坡底最大,中坡最小,叶片数由坡底到坡顶逐渐减少;根冠比在坡底最小(0.36),不同坡位间差异不显著,而比叶面积在坡底最大(241.3 cm2·g-1),坡顶最小(200.1 cm2·g-1),且显著小于坡底和中坡(P0.01)。6.萌生更新是山桃种群实生更新的重要补充。山桃植株的损伤可以一定程度地促进萌条的萌生,从而抵抗外界的干扰,表明萌生对山桃种群更新有重要作用。保留10 cm树桩高度的幼苗萌条数、萌条长和萌条基径均为最大,并显著大于对照幼苗(P0.05)。
[Abstract]:Amygdalus davidiana is a species of vegetation restoration, drought resistant afforestation and important ornamental value in the six Panshan National Nature Reserve. On the basis of the investigation of the seed setting rate and the number of young seedlings and the age composition of the under forest young seedlings, this paper studies the seed diffusion related to the regeneration of the peach population and the seed rest. The effects of mechanical injury on the germination ability of peach seedlings were studied. The results could provide a scientific basis for natural or artificial regeneration and ecosystem management of peach population. The main results are as follows: 1. the species of peach species in this study The year of the group was in a stout year; the slope position and the canopy habitat affected the growth and survival of the seedlings of the peach trees by affecting the light and soil moisture heterogeneity. The fruit weight of the peach population in 2016 (3.44 per plant on the bottom of the slope) and the seed setting rate (0.24%) were very low, and the habitat (canopy gap / canopy) factors were closely related to the seedling bank of the peach forest. There was significant influence (P0.01). The seedling density of canopy gap and canopy was highest at the bottom of slope, and there was significant difference between canopy gap and under canopy habitat (P0.01) at the top of the slope (P0.01). There was no significant difference between the different habitats and different slope positions in other slope positions; the number of seedlings of 2-3 and 4-5 year seedlings in the seedling bank was dominant, and 1 and 6 years old were more than young. The relative less.2. soil coverage was beneficial to the survival of the seeds of the peach; the seed characteristics and the synergism of the rodent handling and storage promoted the seed diffusion. The seed retention rates of soil covered treated seeds were the highest under the density of 1 /m2,4 /m2,9 /m2, respectively, 41.67% and 47.22%, respectively. The seeds treated with litter were relatively low. The storage rate of the density (1 /m2 and 4 /m2) was higher, 16.67% and 18.75%, respectively. There was no significant difference in the distance between feeding and storage after the rodent handling in different coverage and density (P0.05), and the distance of food after handling was larger than the storage distance after carrying. The distance between the feeding and storage of the seeds was covered by litter covered litter and litter. The distribution of litter removal distances was concentrated in 1-3 m, 3-5 m, 5-10 m distance groups, and the litter covered seeds were concentrated in 3-5 m, 5-10 m distance group, and soil cover treatment seeds concentrated on 1 m, 1-3 m, 3-5 m. .3. low temperature stratification in distance group can effectively break the dormancy of peach seed and promote its germination. The best layer accumulation time of peach seeds is 35 d, while the seed germination parameters decrease slightly with the lengthening of stratification processing time, and the germination rate of Peach Seeds decreases with the decrease of light intensity. All germination parameters under 0.5 cm and 1 cm were significantly higher than that of small seeds (P0.05), while the relatively deep sowing depth was not conducive to.4. illumination and water as an important environmental factor affecting the growth and survival of peach seedlings. The plant height of peach seedlings was the smallest (9.9 cm) under the strong illumination (55.4% natural sunlight, NS). The leaf area of the single plant increased first and then decreased with the light intensity, and the growth parameters such as the seedling base diameter, the number of leaves, the length of the main root, the number of the lateral roots, the total dry mass and the root and crown ratio were the largest in 55.4%NS or 18.9%NS, and showed a tendency to decrease continuously or to decrease with the light attenuation; as the light weakened, the root length, the length of the shoot and the specific leaf were longer. The area increased with the decrease of light, and was the largest in 5.5%NS or 2.2%NS. In general, light was beneficial to the growth and dry matter accumulation of peach seedlings. The seedlings had large morphological plasticity under different light intensity. It showed that the light had a strong adaptability to the light conditions in the natural distribution area. Under the influence, the seedlings of peach seedlings can be adapted to the environment by reducing plant height, single leaf area and increasing the root and crown ratio, while sufficient light and water conditions are beneficial to the accumulation of the biomass of peach seedlings. Under 55.4%NS light intensity, the dry quality of the seedlings of 500 ml water per 3 D and 7 d is significantly greater than that of the other seedlings (P0.05).5. at different slope positions. The results showed that the survival rate of the seedlings of peach seedlings showed that the survival rate of the transplanted seedlings was the top slope in the slope bottom, the seedling height, the base diameter, the length of the main root, the number of leaves, the leaf area and the total dry quality were the largest, the middle slope was the smallest, the number of leaves decreased gradually from the bottom to the top of the slope, and the root crown ratio was the smallest (0.36) at the slope bottom. The difference between the different slope positions is not significant, and the specific leaf area is the largest (241.3 cm2. G-1), the top of the slope (200.1 cm2. G-1), and significantly less than the slope bottom and the middle slope (P0.01).6. germination and renewal is an important supplement to the growth of the peach population. The number of seedlings with the height of 10 cm stump, the length of germination and the basal diameter of the sprout were the largest, and were significantly greater than those of the control seedlings (P0.05).
【学位授予单位】：北方民族大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q948.1

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