【作者】 阮志平；

【导师】 林鹏； 李振基；

【作者基本信息】 厦门大学 ， 植物学， 2008， 博士

【摘要】 棕榈科（Palmae）植物是热带地带性植物,多分布在热带与亚热带地区,其种类繁多,近年来已成为我国南方城市绿化的主要树种之一。寒害是棕榈科植物最重要的自然灾害,为了更好对棕榈植物引种与管理提供科学依据,避免因盲目引种而造成的经济损失,本文选择厦门植物园种植的布迪椰子（Butia capitata Becc.）、沼地棕[Acoelorraphe wrightii（Griseb.& H.Wendl.）H.Wendl.ex Becc.]和油棕（Elaeis guineensis Jacq.）3种棕榈科植物进行了耐寒适应性评价与耐寒机理研究。研究结果如下:1.首次提出棕榈科植物的寒害指数,通过调查露地剧烈降温后越冬期间叶片的寒害等级,计算寒害指数。同时通过测定棕榈科植物电解质渗透率,并通过拟合的Logistic方程求其拐点值来确定半致死温度。利用寒害指数、电解质渗透率与半致死温度研究了布迪椰子、沼地棕和油棕3种棕榈科植物在厦门露天栽种的耐寒性,结果表明,它们的寒害指数差异明显,布迪椰子的寒害指数为7.29,在露地能顺利越冬:沼地棕的为20.24,适当保护才能越冬,油棕为75.00,不能在露地越冬。应用Logistic方程分别求出各自的半致死温度(LT₅₀),布迪椰子、沼地棕和油棕在低温锻炼前（10月份）的半致死温度分别为-7.93℃、-5.03℃和-2.19℃,在低温锻炼后（次年1月份）的半致死温度分别为-19.10℃、-6.60℃和-2.94℃。发现布迪椰子的耐寒力最强而且对降温反应速度最快、油棕最弱耐寒力,对温度反应最慢,沼地棕的居中。综合上述的研究结果可作为棕榈科植物北移推广应用的参考模式。2.测定了3种棕榈科植物叶片的角质层、表皮、栅栏组织和海绵组织等厚度,比较了不同耐寒性棕榈植物叶的解剖结构特征,细胞结构紧密度（CTR）、细胞结构疏松度（SR）,结果表明:细胞结构紧密度大小顺序为沼地棕>布迪椰子>油棕,耐寒性最强的布迪椰子细胞紧密度小于沼地棕;细胞结构疏松度大小顺序为布迪椰子=油棕>沼地棕,耐寒性最强的布迪椰子细胞疏松度大于沼地棕,而最耐寒的布迪椰子和最不耐寒的油棕的疏松度相近;3种不同棕榈科植物之间的耐寒性与细胞组织的紧密度和细胞组织的疏松度不具有相关性,所以,对于不同棕榈科植物种之间的耐寒性比较,首先要考虑叶片的结构不同,如布迪椰子有明显的上、下栅栏组织分化,虽然沼地棕也有上、下栅栏组织分化,但是不明显,而油棕却只有上栅栏组织,并没有下栅栏组织产生,而且栅栏组织的细胞较长,所以,要首先应该考虑叶片本身的结构特征与植物的耐寒性的关系,然后再综合考虑叶片厚度、叶面具有角质层厚度、叶肉栅栏组织厚并且排列紧密以及栅栏组织与海绵组织比值等特点,是耐寒性植物叶片的结构特征。3.测定棕榈植物在4个季节自然条件下的总酚、可溶性单宁和缩合单宁等酚类物质含量的变化。比较耐寒性不同的3种棕榈植物叶片总酚含量的季节变化规律,油棕的总酚含量4个季节中都处于最低水平（介于16.2-26.5mg/g）,4个季节的平均含量为21.80mg/g,远远低于其它两种的4个季节总酚含量的平均值;秋季-冬季的变化幅度大小顺序为:油棕（1.76mg/g）>沼地棕（1.24mg/g）>布迪椰子（1.06mg/g）。布迪椰子在春季、夏季和秋季的结合态缩合单宁的含量都保持在较高水平,沼地棕和油棕在秋季和冬季明显下降。布迪椰子的总酚、总缩合单宁和可溶性缩合单宁含量在夏、秋季节最低,生长投入多而减少合成次生代谢物,使其可以在良好自然条件下保持生长速度快,使得在冬季抗寒的过程中更具竞争能力。而油棕的总缩合单宁和可溶性缩合单宁在夏、秋季节最高,既浪费能量又无法在冬季起抗寒作用。所以,耐寒强的棕榈植物体内具有最佳的防寒系统。4.首次利用质谱法MALDI-TOF-MS对耐寒性不同的棕榈植物的单宁结构进行测定和分析比较。结果发现,布迪椰子和油棕两种植物的质谱图中存在两组离子峰系列,主要的离子峰系列（A）m/z为:711-999-1287-1575-1863…,其单宁的结构单元主要为儿茶酚,系列（B）离子峰m/z为:727-1015-1303-1591-1879-2167-2455…,离子峰之间的峰值多m/z 16,其单宁的结构单元主要为棓儿茶酚,该系列的离子峰很可能是由那些在羟基数量上比由U272构成的黄烷三醇聚合物在B环上多一个-OH;它们具有相同的单宁结构,具有相同的R₁和R₂结构,从而可以推测其耐寒性的差异与单宁的结构没有关系。5.首次比较布迪椰子、沼地棕和油棕的幼叶、成熟叶、叶柄和根不同器官在4个季节中的灰分含量、干重热值和去灰分热值,从能量角度揭示其耐寒适应性强弱的能量生态学策略和原理。布迪椰子4个季节干重热值的平均值为成熟叶（20.65kJ/g）>幼叶(19.84kJ/g>根（19.55kJ/g）>叶柄（18.77kJ/g）,秋季的干重热值明显高于其它3个季节的干重热值,冬季的干重热值最低,去灰分热值与干重热值的变化趋势基本相同。灰分含量4个季节的平均值为根（5.14%）>叶柄（4.33%）>幼叶（4.21%）>成熟叶（3.97%）。成熟叶的灰分含量一直维持在比较低的水平,而幼叶在秋季的灰分含量明显下降,在冬季明显上升,幼叶灰分含量的季节变化趋势与成熟叶的相同,叶柄的灰分含量在冬季明显低于根部。布迪椰子不同器官在不同季节的热值和灰分的变化规律显示其具有较强的耐寒适应性。沼地棕不同器官在4个季节中的平均干重热值大小顺序为成熟叶（20.46kJ/g）>幼叶（19.50kJ/g）>根（19.34kJ/g）>叶柄（18.48kJ/g）,并且经t检验,根与成熟叶之间无显著差异（p>0.05）,沼地棕不同器官的变化趋势与布迪椰子类似。沼地棕的不同器官在4个季节中的平均灰分含量高低顺序为成熟叶（6.18%）>幼叶（5.19%）>根（4.87%）>叶柄（4.56%）,成熟叶的平均灰分含量显著高于其它器官。油棕不同器官在4个季节中的平均干重热值高低顺序为成熟叶（19.73kJ/g）>根（19.33kJ/g）>幼叶（19.06kJ/g）>叶柄（18.17kJ/g）,并且经t检验,根与成熟叶的干重热值无显著差异（p>0.05）,成熟叶从夏季到秋季期间几乎不变,冬季下降。油棕的不同器官在4个季节中的平均灰分含量的高低顺序为根（7.01%）>成熟叶（6.78%）>叶柄（5.31%）>幼叶（5.28%）,根和成熟叶的平均灰分含量显著高于幼叶和叶柄。布迪椰子和沼地棕的幼叶和成熟叶的干重热值均与灰分含量具有极显著线性负相关,而油棕只有成熟叶的干重热值均与灰分含量具有显著线性负相关,本研究中3种棕榈植物的叶柄和根均与灰分含量没有有显著线性负相关,说明灰分的含量对干重热值没有造成影响。更多还原

【Abstract】 Palms are widely distributed in tropical and subtropical area, which have been widely introduced into many cities of Southern China for landscape. Cold injury is the most serious factor that limits them to grow in the introduced area.Experiments were conducted to evaluate the adaptation and mechanism to endure cold of Butia capitata Becc, Elaeis guineensis Jacq. and Acoelorraphe wrightii （Griseb.& H. Wendl.） H. Wendl. ex Becc. cultivated in Xiamen Botanical Garden. The results the research were summarized as follows:1.The cold injury index （CI） of palms was proposed to weigh the cold endurance. The results showed that the CI of Butia capitata, Elaeis guineensis and Acoelorraphe wrightii was 7.29, 75.00 and 20.24 respectively. The electrolyte leakage of leaves was measured in October and January under different temperature, and the semi-lethal low temperature (LT₅₀) of leaves was assayed in different sampling period by Logistic equation. The LT₅₀ of Butia capitata., Acoelorraphe wrightii and Elaeis guineensis was -7.93℃,-5.03℃and -2.19℃respectively in October, -19.10℃,-6.60℃and -2.94℃respectively in January. The results showed that the sequence of the cold tolerance was: Butia capitata>Acoelorraphe wrightii >Elaeis guineensis. We can also apply the model of the three palm species in different cities, and can also predict the cold resistance of other palm species.2. The anatomical features of leaves of 3 palm species were surveyed and analyzed firstly. The morphological features of structure were described and stated thoroughly by means of optical microscopy. Calculating the ratio of spongy/palisade tissues, The results of CTR and SR followed the order: Acoelorraphe wrightii>Butia capitata>Elaeis guineensis. and Butia capitata-Elaeis guineensis>Acoelorraphe wrightii, respectively. The results showed the CTR and SR are not related to the cold resistance. The different cold resistance of three palms have different palisade tissues, Therefore, the features of anatomy and structure of leaves should be considered first, then structural quantity be considered secondly to explain the cold resistance.3. The studies on the seasonal changes of extractable total polyphenol content（ETP）、soluable condensed tannins（SCT）、BCT and total condensed tannins（TCT） content of palm leaves were conducted for the first time. The content extractable total polyphenol content（ETP） of Elaeis guineensis in the four seasons was the lowest, varying from 16.20mg/g to 26.5mg/g. The annual average content of Elaeis guineensis leaves was 21.80mg/g. It was much lower than that of Butia capitata and Acoelorraphe wrightii. From autumn to winter, the range of extractable total polyphenol content（ETP） was in the following order: Elaeis guineensis（1.76mg/g） >Acoelorraphe wrightii（1.24mg/g）>Butia capitata（1.06mg/g）.The content of BCT was higher in the leaves of Butia capitata in the spring and summer and autumn.markedly decreased for the Acoelorraphe wrightii and Elaeis guineensis in the winter and autumn. This indicated the Butia capitata with much more efficient photosynthesis, while the decreasing content of Acoelorraphe wrightii and Elaeis guineensis may be related with the low photosynthesis.The high cold resistant Butia capitata had minimum content of total polyphenol content（ETP）, soluable condensed tannins（SCT） and total condensed tannins （TCT） in the summer and autumn, in order to reduce the investment for the second-metabolism and to keep more investment for the cold resistance in the winter. However, The content of total condensed tannins（TCT） and soluable condensed tannins（SCT） in Elaeis guineensis leaves was in the maximum in the summer and autumn, This was not a good energy strategy for adapting to the low temperature.4. For the first time to characterize the authentic tannins chemical structure in the mature leaves by MALDI-TOF in palms, The spectra obtained through MALDI-TOF-MS analysis revealed the presence of two series of tannin oligomers. The first series consists of m/z 711-999-1287-1575-1863..., and the second series consists of m/z 727-1015-1303-1591-1879-2167-2455..., and different cold resistant species have the same structure of R₁ and R₂,From this can estimate that there is no relationship between the cold resistance and tannins chemical structure in the palms’cold resistance.5. The gross caloric value（GCV） and ash free caloric value（AFCV） and ash content of different components of three different cold resistant palms were studied for the first time with an oxygen bomb thermometer.The annual average caloric value of Butia capitata was in the following order: mature leaves（20.65kJ/g）>young leaves（19.84kJ/g）>roots（19.55kJ/g）>petioles（18.77kJ/g）.The components showed maximum gross caloric value（GCV） in autumn and minimum one in winter. Ash free caloric value（AFCV） varied as same as gross caloric value（GCV）. The annual average ash content followed the order: roots（5.14%）>petioles（4.33%）>young leaves（4.21%）>mature leaves（3.97%）. The ash content was lower in mature leaves, markedly decreased in young leaves during autumn, and then increased during winter. Seasonal changes of ash content in mature leaves were the same as those in young leaves. Petioles had much lower ash content than roots in winter. Changes in ash content and caloric value of Butia capitata in different seasons reflected the good energy strategy for species with high cold resistance to adapt to the low temperature.The annual average gross caloric value of Acoelorraphe wrightii was in the following order: mature leaves（20.46kJ/g） > young leaves（19.50kJ/g） > roots（19.34kJ/g）> petioles（18.48 kJ/g）, There was no significant difference between roots GCV and mature leaves GCV （p>0.05）, The GCV of Acoelorraphe wrightii had the same trends of seasons’ change as Butia capitata. The annual average ash content followed the order: mature leaves（6.18%）>young leaves（5.19%）>roots（4.84%）>petioles（4.56%）. The mature leaves had the highest ash content value.The annual average gross caloric value of Elaeis guineensis was in the following order: mature leaves（19.73kJ/g）>roots（19.33kJ/g）>young leaves（19.06kJ/g）>petioles（18.17kJ/g）, There was no significant difference between roots GCV and mature leaves GCV（p>0.05）, The GCV of Elaeis guineensis in summer was almost the same as that of autumn. The annual average ash content followed the order: roots（7.01%） > mature leaves（6.78%）> petioles（5.31%）>young leaves（5.28%）. The roots and mature leaves had the higher ash content value than those of young leaves and petioles.The gross caloric value was negative correlated remarkably with ash content for young leaves and mature leaves of Butia capitata and Acoelorraphe wrightii, there was only for mature leaves of Elaeis guineensis. Whereas there was no significant negative correlation between gross caloric value and ash content for petioles and roots of the three palms.更多还原