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鄂尔多斯高原4种主要沙生植物种子萌发与出苗对水分和沙埋的响应
引用本文:聂春雷,郑元润.鄂尔多斯高原4种主要沙生植物种子萌发与出苗对水分和沙埋的响应[J].植物生态学报,2005,29(1):32-41.
作者姓名:聂春雷  郑元润
作者单位:中国科学院植物研究所植被数量生态学重点实验室,北京100093
基金项目:中国科学院院长基金,中国科学院资源与生态环境研究项目,国家科技攻关项目
摘    要: 羊柴 (Hedysarum leave)、柠条 (Caragana korshinskii)、籽蒿 (Artemisia sphaerocephala)与油蒿 (Artemisia ordosica)为鄂尔多斯高原广泛分布的植物种,也是该地区飞播选用的主要植物种。由于飞播为鄂尔多斯高原植被恢复的重要手段,而飞播后植物种子的出苗率与土壤水分及沙埋密切相关。因此,上述植物种子萌发与出苗对水分和沙埋反应的研究对当地退化生态系统的恢复具有重要意义。通过温室控制实验,对4种植物萌发特性及出苗与水分和沙埋深度的关系进行研究,阐明了种子萌发最适合的水分条件和沙埋深度。结果表明,4种植物种子萌发与出苗最适宜的供水量都接近于当地种子萌发时期的平均降水量, 最适宜的沙埋深度为0.5~1 cm, 过多的水分和过深的沙埋会降低种子萌发与出苗,反映了4种植物对沙区环境的生态适应。4种植物最适宜的供水量均为123 ml,羊柴、柠条、籽蒿和油蒿的最适沙埋深度分别为:0.5、1.0、0.5和0.5 cm。根据实验结果及当地气候特点,鄂尔多斯地区的飞播时间应由6月初提前至5月中下旬,以提高飞播植物的出苗率。

关 键 词:鄂尔多斯高原  水分  沙埋  种子萌发  幼苗出土
修稿时间:2004年5月26日

EFFECTS OF WATER SUPPLY AND SAND BURIAL ON SEED GERMINATION AND SEEDLING EMERGENCE OF FOUR DOMINANT PSAMMOPHYTES IN THE ORDOS PLATEAU
NEE Chun-Lei and ZHENG Yuan-Run.EFFECTS OF WATER SUPPLY AND SAND BURIAL ON SEED GERMINATION AND SEEDLING EMERGENCE OF FOUR DOMINANT PSAMMOPHYTES IN THE ORDOS PLATEAU[J].Acta Phytoecologica Sinica,2005,29(1):32-41.
Authors:NEE Chun-Lei and ZHENG Yuan-Run
Affiliation:(Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China)
Abstract:The Ordos Plateau of North China has experienced serious desertification. Hedysarum leave, Caragana korshinskii, Artemisia sphaerocephala and A. ordosica are four dominant psammophyte species that inhabit the Mu-Us Sandland, Ordos Plateau that are used in aerial seeding, a primary method for vegetation restoration in deserts and sand lands, in the Ordos Plateau, Seedling emergence is closely related to sand burial depth and water content of the soil but survival is low. In this paper, seed germination and seedling emergence characteristics of the four species in response to different levels of water availability and burial depth were studied and compared to determine the optimal time for aerial seeding to enhance seedling emergence and improve vegetation restoration efforts. The experiment was conducted in a non-heated greenhouse at the Ordos Sandland and Grassland Ecological Station of the Chinese Academy of Sciences in the summer of 2003. All seeds used in the experiment were collected from their natural habitat near the ecological station. The seed mass (mean±SE) varied among species: H. leave, (11.70±0.9) mg; C. korshinskii, (34.15±2.2) mg; A. sphaerocephala, (0.67±0.12) mg; A. ordosica, (0.22±0.09) mg. Seed germination, tested under the same environmental conditions, also varied among species: H. leave, (65.6±4.8)%; C. korshinskii, (52±4.7)%; A. sphaerocephala, (94.4±1.6)%; A. ordosica, 95.2%±0.8%. Each species was grown at seven sand burial depths (0, 0.5, 1, 1.5, 2, 3, 5 cm) under three water supply regimes (123, 185, 246 ml). The different water treatments corresponded to mean monthly precipitation levels of 50, 75, and 100 mm during growing season (from June to September). The average monthly precipitation in June in this area was about 50 mm. There were 21 treatments for each species with 5 replicates of each treatment. Each replicate consisted of 25 seeds planted in a plastic pot 5.6 cm in diameter and 11 cm in height with a drainage hole at the bottom of pot. Seedling emergence was checked and recorded everyday and water was added every three days. The experiment was terminated after 30 days when the seedling emergence became almost steady. The number of seedlings that did not emerge was quantified. As the main purpose of this study was on seedling emergence, dormant and decomposed seeds were counted as non-germinated. For each species, sand burial depth, water supply regime, and their interactions all had significant effects on the percentage and the rate of seedling emergence. All seeds lying on the soil surface did not germinate. The optimal burial depth for H. leave, C. korshinskii, A. sphaerocephala and A. ordosica was 0.5, 1, 0.5, and 0.5 cm, respectively. As the sand burial depth increased, the percentage and rate of seedling emergence decreased and the emergence time was delayed, but the percentage of seedlings that did not emerge was not affected. Seeds of A. sphaerocephala and A. ordosica could not emerge from burial depths greater than 1.5 cm, but seeds of H. leave and C. korshinskii were able to emerge from depths of 2-3 cm. This difference may be because of the greater mean seed mass of H. leave and C. korshinskii. The tolerance to sand burial depth was in the following order: H. leave> C. korshinskii > A. ordosica> A. sphaerocephala. The optimal water supply for all four species was 123 ml, which was close to the mean monthly precipitation of June (50 mm), the time when most seedling emergence occurs in the Ordos Plateau. As the amount of water increased, the percentage and rate of seedling emergence decreased and the emergence time delayed, but the percentage of seedlings that did not emerge was not affected. The maximum percentage (mean±SE) of seedling emergence of these four species was H. leave, 56.80%±1.96%, C. korshinskii, 39.20%±5.12%; A. sphaerocephala, 62.4%±4.12%; and A. ordosica, 77.6%±9.85%. Too much water and too deep of burial reduced the percentage of seedlings that emerged. This reflected the adaptation of the plants to the local climate and environment. In the Ordos Plateau, aerial seeding is often conducted during early June. Based on our results, weather conditions are not suitable for seedling establishment during this time because wind speeds are low, and the seeds are not buried by the sand. Our results indicate that this may reduce the percentage of seedlings that emerge as all four species require sand burial. During middle and late May, the winds are stronger and the seeds have a greater chance of being buried at their optimal depth. Even though there is no precipitation or the seeds might be buried too deep, they can survive in the soil and emerge later under more favorable conditions. Therefore, it is suggested that the time of aerial seeding be advanced from early June to mid to late May in order to enhance the emergence of the seedlings.
Keywords:Ordos Plateau  Water supply  Sand burial  Germination  Seedling emergence  
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