霸王种子在达坂城原生境的萌发和休眠

发布时间：2018-04-17 19:43

  本文选题：霸王 + 埋放种子　； 参考：《新疆师范大学》2017年硕士论文

【摘要】：霸王(Zygophyllum xanthoxylon)为蒺藜科超旱生灌木,是达坂城荒漠植被的优势种,是植被恢复的潜在候选植物种。本研究通室内实验和野外观测,对霸王在达坂城原生境埋放及植冠宿存的种子进行了研究,并调查其霸王在自然条件下出苗的时空格局,对其种子萌发阶段对达坂城极端干旱和长期大风环境的适应对策进行了探讨,主要结论如下:(1)霸王种子成熟时有部分种子(39%)存在休眠。在达坂城地区,季节性水热条件的变化能够影响种子的萌发和休眠。鲜种子的休眠在原生境埋放6周后逐渐解除,秋季(2015年9月)萌发率升高;埋放18周后经过冬季的低温层积后休眠基本解除,冬季(2015年12月)取回的种子在5/15℃下萌发率提高到87%以上;直到埋放42周后(2017年6月),有少部分种子(约21-49%)在夏季进入次生休眠,种子萌发的温度范围改变,萌发率在高温下(25/15℃、30/15℃)降低;直到之后的秋季,埋放54周(2017年9月)的种子休眠解除,萌发率再次升高;埋放70周(2017年12月)的种子经过第二年冬季低温层积后萌发率均在97%以上,仍有93%以上的种子有活力。在较高温度下地表种子比土中具有更高的萌发率。在达坂城荒漠,土壤中埋放的霸王种子具有季节性的条件休眠/非休眠的循环。(2)在达坂城地区,植冠宿存4、6个月后的种子萌发率仍在93%以上。霸王植冠宿存6个月的种子萌发率明显高于地表种子。植冠种子的活力高于地表种子,植冠宿存有利于种子活力的保持。(3)在达坂城地区,霸王在整个生长季内均能出苗,5月、6月、7月、8月、9月、10月出苗数分别为0.02株/m2、0.4株/m2、2.9株/m2、0.7株/m2、5.8株/m2、2.4株/m2,出苗的主要季节是秋季。出苗的微生境主要在麻黄丛、低洼裸地、单株霸王背风面。
[Abstract]:Zygophyllum xanthoxylon is a super xerophytic shrub of Tribulus terrestris family. It is the dominant species of desert vegetation in Dabancheng and a potential candidate for vegetation restoration.Through laboratory experiments and field observation, the seeds planted and planted in the original habitat of Dabancheng were studied, and the temporal and spatial patterns of Seedling emergence under natural conditions were investigated.In this paper, the adaptation strategies of Dabancheng extreme drought and long term strong wind environment during seed germination were discussed. The main conclusions are as follows: 1) some seeds have dormancy when they mature.In Dabancheng, seasonal changes in water and heat conditions can affect seed germination and dormancy.The dormancy of fresh seeds was gradually released after 6 weeks of planting in the original habitat, and the germination rate increased in autumn (September 2015), and after 18 weeks of burial, the dormancy was basically relieved after the cold stratification in winter.In winter (December 2015), the seed germination rate increased to more than 87% at 5 / 15 鈩，

本文编号：1765007