【作者】 陈歆；

【导师】 周兆德； 杨福孙；

【作者基本信息】 海南大学 ， 生态学， 2010， 硕士

【摘要】 槟榔(Areca Catechu L.)系棕榈科(Palmae)热带经济、药用作物；在中国,多分布在海南、台湾等地。目前,槟榔产业为海南农业第二大支柱产业。海南槟榔种植技术落后,管理粗放,基础研究力度不够,已明显制约了产量的提高及产业的发展。海南岛属典型热带海洋气候,具有明显的雨季与旱季。因水分时空分布不均匀造成的干旱已严重影响了槟榔的生长及产量,尤其在每年3—5月槟榔的开花期影响更为突出。因此研究土壤水分胁迫下槟榔生长的生理变化规律,对提高槟榔水分管理水平,促进槟榔产业发展具有重要意义。本研究以1年生槟榔幼苗为材料,从植物生理生态学角度出发,采用盆栽试验,通过控制土壤相对含水量,首先研究了不同土壤水分胁迫下,槟榔幼苗的形态、抗性生理、光合生理等的变化规律；其次通过数据处理建立土壤水分相对含量与槟榔幼苗的光合生理、水分利用效率等的数学模型；最后结合生理数据与数学模型确定了槟榔苗期适宜生长的土壤相对含水量阈值与最低限值,为槟榔合理的水分管理提供依据。本研究创新点及主要结论如下：(1)研究了土壤水分胁迫对槟榔幼苗生长及形态的影响。研究表明,土壤水分胁迫下,槟榔幼苗的株高、冠幅、茎粗、根系数目、根表面积和根体积均随水分胁迫程度的加重而减少。且明显影响了槟榔幼苗植株体内水分的分配,各处理下的槟榔幼苗各部分水分分配均呈现叶>茎>根的现象。随着土壤相对含水量升高,根系含水率升高,叶片含水率降低,茎含水率无明显变化。而随水分胁迫程度的加深槟榔幼苗根冠比值呈现先升高后下降趋势。(2)研究了土壤水分胁迫对槟榔幼苗抗性生理的变化规律。土壤水分胁迫显著增加了槟榔幼苗叶片中MDA和渗透调节物质的含量。随着胁迫时间延长,各处理下槟榔幼苗叶片中的MDA含量、Pro含量、SS含量与SP含量均不同程度上升,且叶片中Pro含量与槟榔幼苗对土壤水分胁迫的响应时间存在相关性。叶片中的保护酶POD及SOD活性均呈先上升后下降趋势,而CAT活性呈先下降后升高趋势；土壤水分胁迫时间越长,叶中POD与SOD活性随胁迫程度增加而降低的现象越明显。槟榔幼苗的根系活力随土壤水分胁迫程度增加而减小。并认为75%土壤相对含水量是槟榔幼苗根系活力变化的转折点。(3)研究了土壤水分胁迫与槟榔幼苗光合生产能力的关系。结果发现：随土壤水分胁迫时间延长和胁迫程度增加,槟榔幼苗叶片总的叶绿素含量降低,且chl、cha、chb、caro、cha/b均以75%土壤相对含水量处理显著高于其它处理。不论土壤水分胁迫时间长短,随土壤水分胁迫程度增加,叶片Pn、Tr、cond均逐渐下降,但幼苗水分利用率(WUE)升高,并随着胁迫时间延长,各处理间槟榔幼苗水分利用率的差异性会削弱。土壤水分胁迫下槟榔幼苗叶片Fv.Fm、qP. Fv／Fm和Fv／Po均下降,Fo增加。表明土壤水分胁迫抑制了槟榔幼苗的PSⅡ原初光能转化效率,降低了光合电子传递能力及PSⅡ的光化学活性。(4)对不同土壤水分胁迫下槟榔幼苗净光合速率、蒸腾速率的影响因子进行了相关分析,并拟合不同土壤水分胁迫下的逐步回归方程,建立了土壤水分相对含量与净光合速率、土壤水分相对含量与蒸腾速率和土壤水分相对含量与水分利用效率的数学模型。Pn=-0.0018x2+0.2939x-5.5679, R2=0.9981Tr=-0.0016x2+0.2652x-6.0083, R2=0.9438WUE= 2E-06x4-0.0005x3+0.0404x2-1.4562x+20.54, R2=0.8674(5)首次确定了槟榔苗期适宜生长的土壤相对含水量与最低土壤水分限值。通过建立模型并结合生理研究结论发现,槟榔幼苗能够生长的最低土壤水分相对含量为45%,但从光合物质积累和水分利用效率这两个角度考虑,土壤相对含水量75%左右更有利于槟榔幼苗的生长。更多还原

【Abstract】 Betel nut(Areca Catechu L),a member of the family Palmae, is tropical-economic-medicational crop, which has been the second rank of major industries. Due to outdate technology, extensively manage and deficiency of investigation, Betel nut industry has been restricted to low production. Hainan island is typical tropical ocean climate, with significantly rainy season and dry season.drought have significant effect on its growth and production, particularly during the efflorescence-from March to May every year.Therefor study on regularity of physical growth of betel nut have significant contribution to promote development of Betel nut industry by improving the management of threshold value。This study based on plant physiological ecology theory, annual growth betel nut was used as material in pot experiment, analysis its growing mechanism indexs such as seedling morphology、physical resistance and photosythese under different soil water stress fristly. Then establish the relationship model between soil relative moisture content、seedling photosynthesis and water utilization, finally analyzed the physiological datas and the models to find out the optimal and minimum threshold of soil relative moisture content, providing a reasonable basis for its water management. Finally finding the suitable relative soil water content and the minimum threshold limit relative soil water content for the finalization of betel nut seedling’s growth, providing a reasonable basis for water management for the betel nut.In the dissertation, innovations conclusions were as follows:(1) Effect soil water stress on betel nut seedling growth and morphology. The results showed that betel nut seedlings’plant height, crown width, stem diameter, root number, root surface area and root volume decreased with the aggravation of water stress. Soil water stress significant effected water distribution in seedlings’body and it kept the rule as leaf> stem> root. According to soil water content increasing, root moisture content increased, leaf water content decreased,while no significant changes in stem water content. With the deepening of water stress betel nut seedling shoot ratio has increased firstly and then decreased.(2) Physiological resistance changes of betel nut seedling under soil water stress. The results indicated that soil moisture stress obviously enhanced the MDA content and osmotic adjustment substances in leaves and with the stress added,the MDA content, Pro content, SS content and SP content in leaves under different treatments were all increased in various degrees. Meanwhile, the Pro content had strong correlated to soil water stress time. The protective enzymes such as POD and SOD activity increased firstly and then decreased, while the CAT activity was in opposite changes under the soil water stress. Generally the POD and SOD activity in leaves would reduce as the extent of soil water stress increase. Betel nut seedlings’root activity would turn down when soil water stress increased. And the 75% relative soil water content was the turning point of its’root activity.(3) The relationship between soil water stress and photosynthetic capacity of betel nut seedling. It elaborated that with the water stress’time prolonged and stress level increased, chlorophyll content of betel nut decreased, the content of chl、cha、chb、caro、cha/b belong to betel nut seedling all dealing with 75% relative soil water content were distantly higher than others treatments. No matter how long the betel nut under the water stress, as soon as the soil water stress degree increased, betel nut seedling’s Pn, Tr, cond all decreased, while seedlings’water efficiency increased. And in the prolonged stress period, the difference among different treatment would be weaken. betel nut seedlings’Fv, Fm, qP, Fv/Fm and Fv/Fo decreased under soil water stress, while Fo increased. It proved that water stress has inhibited the original PSⅡphotochemical efficiency, reduced photosynthetic electron transport capacity and the PSⅡphotochemical activity.(4) Analysis the correlation impacting factors of net photosynthetic rate and transpiration rate under different soil water stress, and fit stepwise regression equations under different soil water stress, establish the mathematics relationship models of the soil moisture content and net photosynthetic rate, and transpiration rate,and water use efficiency individually. The models as follow:Pn=-0.0018x2+0.2939x-5.5679, R2= 0.9981Tr=-0.0016x2+0.2652x-6.0083, R2= 0.9438WUE= 2E-06x4-0.0005x3+0.0404x2-1.4562x+20.54, R2= 0.8674(5)The research quantize the most suitable relative soil water content and the lowest soil moisture limits for betel nut seedling’s growth for the first time. Through establishing the model and integrateing with physiological characters, it found that 45% relative soil moisture content was the lowest soil water condition for its growth. However considered the dry matter accumulation and water use efficiency, approximately 75% relative soil water content was more beneficial to betel nut seedling’s growth.更多还原