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3种增温处理对夏蜡梅幼苗生长与生物量分配的影响

金则新1*，徐兴利2，何维明3

(1. 台州学院生态研究所, 临海 317000; 2. 重庆开县林业局, 开县 405400; 3. 中国科学院植物研究所

植被与环境变化国家重点实验室, 北京 100093 )

摘要：利用红外线辐射器（Electric radiant infrared heater）设置了全天增温（AW）、晚上增温（NW）、白天增温（DW）3种处理，以不做增温处理作为对照（CK），模拟气候变暖对夏蜡梅（Sinocalycanthus chinensis）幼苗生长与生物量分配的影响。结果表明：（1）不同增温处理的夏蜡梅幼苗株高均比CK高；3种增温处理间的株高以DW最高，AW次之，NW最低；不同增温处理的基径在生长季节的后期均显著高于CK。（2）增温处理的总根长、总根表面积高于CK，3种增温处理之间以DW最高；根平均直径、总根体积为DW高于CK。（3）不同增温处理的总叶周长、总叶长、总叶面积均高于CK，3种增温处理之间均以DW最高；总叶宽为DW大于CK。（4）不同增温处理后的株鲜重、根鲜重、茎鲜重、叶鲜重要高于CK，3种增温处理之间以DW最重。（5）株干重、根干重、茎干重、叶干重在7月到10月不同增温处理均显著高于CK，3种增温处理之间以DW最重。（6）不同增温处理后根冠比显著高于CK，说明增温使地下生物量分配比例上升。总之，增温处理促进了植物生长，尤其DW处理最明显。其原因可能是温度升高提高了植物光合作用能力，增加了光合产物的积累，加快了植物的生长；也可能是增温提高了土壤温度，进而促进了根系的吸收。

关键词：增温；夏蜡梅；幼苗；生长；生物量分配

Effects of three kinds warming on the seedings growth and biomass allocation of Sinocalycanthus

chinensis

JIN Zexin1*，XU Xingli2，HE Weiming3

1 Institute of Ecology, Taizhou College, Linhai 317000, China 2 Forestry Bureau, Chongqing Kaixian, Kaixian 405400, China

3 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093，China

基金项目：国家自然科学基金项目（30870392）和浙江省自然科学基金项目(Y3080460) 收稿日期： 修订日期：

*通讯作者 Corresponding author. E-mail: jzx@tzc.edu.cn

It is now predicted that global temperature will be 1-6 ℃ warmer by the year 2100. Environemtnal warming is likely to have significant effects on plant carbon relations, particular through its effect on photosynthesis and respiration. In terrestrial environments, the night-time daily minimum air temperature increased more than the rate of increased in daytime maximum air temperature. Understanding how plant response to different day/night warming can help to actually predict the plants’ response to global warming. Most of the studies focused on the growth of dominant species or invasive species, little attention has been paid to the endangered plants, which might be important to understanding how endangered species adapt in the context of global warming. Sinocalycanthus chinensis is an endangered plants belonging to Calycanthaceae family. Here we analyze the effect of differential simulated day/night warming on the seeds germination and seedling growth of S. chinensis. Three different simulated day/night warming treatments were included in the experiment: 1) warming of 2℃ at daytime (DW); 2) warming of 2℃ at nighttime (NW); 3) warming of 2℃ at both daytime and nighttime (AW). Seedlings exposed to the mbient temperature without warming were used as control (CK). In October, the total root length and the total root surface area in three treatments were significantly higher than that in CK. The total root length, toal root surface area, the mean root diameter and total root volume in DW were the highest. From June to October, the total leaf perimeter and total leaf length were significantly higher than those of CK with highest in DW treatment. From July to October, the total leaf area in three treatments were significantly higher than that in CK with the highest in DW. This indicated that the DW treatment could benefit the growth of S. chinensis seedlings. This reflected well the growth condition of S. chinensis seedlings and the promotion effect of DW. There was no significant difference of the leaf fresh weight between NW and CK in October, from July to October, the plant, root, stem and leaf fresh weight in three treatments were significantly higher than those in CK with the highest in DW. From July to October, the plant, root, stem and leaf dry weigh and the plant height in three treatments were significantly higher than those in CK with the highest in DW. Form July to October, the basal diameter in three treatments were significantly higher than that in CK without significant differences among three threements, which might be due that simulating warming could promote the plant photosynthesis, the accumulation of photosynthetic products and the growth rate of S. chinensis or increase the absorbtion of root. The root shoot ratio of S. chinensis in three treatments were significantly higher than those in CK,

indicating that simulating warming could allocate more biomass into root.

Keywords：warming; Sinocalycanthus chinensis; seedling growth; biomass allocation

以全球变暖和大气CO2浓度升高为主要特征的全球变化正在改变着陆地生态系统的结构和功能，威胁着人类的生存与健康，因而倍受世界各国政府和科学家的普遍关注[1]。大量的研究表明，到本世纪末全球地表平均温度还将上升1.1~6.4℃[2]。温度是植物生长的必需条件，温度变化不仅会影响地表植被的种群及群落结构，而且会影响各种植物的生长发育与繁衍。温度变化主要通过影响植物的繁殖、叶片和高度等从而影响植物的生长和发育，而叶片生长对增温的反应最为明显[3]。温度变化还通过影响植物根温来影响植物的生长和发育，地温变化1℃就能引起植物生长和养分吸收的明显变化[4]。温度的变化将改变群落小环境，而特殊小生境将影响植物冠层高度、光合速率、养分的吸收和生长率等[5-7]。

夏蜡梅（Sinocalycanthus chinensis）为蜡梅科(Calycanthaceae)夏蜡梅属（Sinocalycanthus）的落叶灌木，为较耐荫树种，主要集中生长在溪沟两旁的沟谷地段和常绿阔叶林下，成为常绿阔叶林下木层的优势种以及次生灌丛的主要建群种[8]。夏蜡梅作为第三纪孑遗物种，现资源极少，主要分布于浙江临安市西部狭小的范围内、天台县大雷山和安徽绩溪龙须山，已列为国家2级重点保护植物[9]。夏蜡梅自60年代在临安被发现以来，受到众多研究工作者的广泛关注。至今对夏蜡梅的生物学特性、群落特征、生理生态、繁殖生态、遗传多样性、空间遗传结构与分子系统地理学等进行了大量的研究，对夏蜡梅的濒危现状、过程以及机理有了初步的了解[10]。目前全球气候变化已经成为不容置疑的事实，而植物生长及生理特性与气候等环境因子密切相关，已有研究表明，模拟增温可提高夏蜡梅的光合作用能力，其中以白天增温最为明显[11]，但是有关模拟增温对夏蜡梅幼苗的生长与生物量分配的研究尚未报道。本文研究模拟增温对夏蜡梅幼苗生长与生物量分配的影响，以期阐明在全球变化条件下，夏蜡梅的生长、发育规律，了解夏蜡梅对未来全球气候变暖的适应能力，为全球变化背景下，濒危植物夏蜡梅的繁衍和保护提供理论依据。

1 研究方法

1.1 增温处理

增温装置采用美国Kalglo Electronics公司生产的红外线辐射器（Electric radiant infrared heater，Model MR-2420）[12]。灯管悬挂按南北方向在样地上方，离地面高度为2.25m，可