【作者】 顿颖；

【导师】 彭抒昂；

【作者基本信息】 华中农业大学 ， 设施园艺， 2011， 硕士

【摘要】 自然条件下生长的柑橘砧木主要是依靠在植株根部形成的菌根,由于在无土栽培条件下砧木根部不会形成菌根,所以如何创造一个有利于砧木根系生长的环境成为许多学者关注的焦点。另外,砧木栽培在土壤中不利于观察其根系形态,利用水培可以在不伤害根系的情况下直观、清晰地看到其形态的变化,通过适当改变营养液配方能方便快速的形成缺素环境。对于缺素条件下柑橘生长的研究比较多,但缺素对柑橘砧木形态方面的研究并不多。因此,本文测定了营养液不同通气频率下枳壳幼苗的生长及生理生化指标,以反映出营养液中不同的含氧量对枳壳生长的影响,并且通过营养液缺N和缺Fe处理,对枳壳幼苗的根系形态指标进行了测定,主要结果如下：1柑橘水培体系的优化(1)不同通气处理对枳壳幼苗生长量的影响与营养液中不通氧处理的枳壳(对照)相比,各通气处理的植株高度随着处理时间的延长显著增加,其中T1处理的株高在后期增幅较大。通气处理的叶面积变化趋势均为前8周较缓慢,处理8至12周内增长速度较快。T1植株的叶面积较处理前有了明显的变化,由4.395cm2增加到60.383 cm2。各通气处理的单株地上部及根部干鲜重在前期变化比较缓慢,后期植株生长较快,干物质累积显著。(2)不同通气处理对枳壳幼苗生理生化的影响与对照相比,各通气处理的电导伤害率值显著较低,T1与T2的变化幅度较小,T3和T4处理的电导伤害率值较高。T1至T4处理由于通气频率逐渐降低,其MDA含量相应逐渐升高,说明增氧可抑制MDA的产生,增加植物活力,抗老化。T1至T4处理的根系活力值在处理相同天数后均高于对照CK的值,高频率通气处理T1和T2的根系活力差异不显著。T1处理的可溶性蛋白含量变化最平稳,T2至T4处理的可溶性蛋白含量变化也不大,均在一定范围内波动。T1、T2和T3处理的可溶性糖含量峰值出现在处理后第8周,较处理前分别增长了42.65%、61.10%和70.61%。T1处理在所有处理中一直保持较高水平的光合色素含量,叶绿素a、总叶绿素和类胡萝卜素含量的最大值均出现在处理后8周。T2、T3和T4处理的光合色素含量变化不大,均在一定范围内波动。2 N、Fe胁迫下枳壳幼苗根系形态研究(1)缺氮和缺铁对枳壳幼苗生长量的影响以在全营养液中生长的枳壳为对照,对照植株株高为44.0cm,而缺氮和缺铁处理植株仅为16.4cm和27.6cm。对照植株的叶面积显著高于缺氮和缺铁植株。缺氮处理的植株在干物质累积方面明显低于对照,缺铁处理的植株生物量介于对照和缺氮处理之间。(2)缺氮和缺铁对枳壳幼苗根系形态的影响缺氮和缺铁处理的植株主根直径略有下降,三种处理的侧根平均直径差异不大,缺氮植株具有明显较大的根体积。缺氮处理使枳壳幼苗的主根长度和根系总长度增加,但侧根数量明显减少,缺铁处理主根长度最大,但其根系总长度却受到抑制,侧根数量也明显减少。缺氮和缺铁处理的植株根系活力显著下降,缺氮处理具有较大的根系表面积,缺铁处理则根系表面积有所下降。(3)缺氮和缺铁对枳壳幼苗营养元素含量的影响缺氮处理的植株N、P含量在根、茎、叶中均较低,缺铁植株只有根部的含N量低于CK对照,缺氮和缺铁处理的植株根部的K含量都显著低于对照,而在茎和叶中差异不大。缺铁处理根部的Fe浓度显著低于对照和缺氮处理,而在茎和叶中差异不大。缺氮、缺铁处理和对照在Ca和Mg含量上并无差异,表明这两种缺素处理对Ca和Mg的吸收影响不大。更多还原

【Abstract】 Under the natural conditions, the growth of citrus rootstocks mainly depends on the mycorrhiza which formed in plant roots.Since there is no mycorrhizal roots in the soilless culture, how to create a conducive environment for the rootstocks to grow becomes the focus of attention of many scholars.Besides,it’s not convenient for us to observe the root morphology of the rootstocks which are planted in the soil, hydroponics can be used without harm to see the shape changes of the root visually and clearly.Nutrient deficiency environment can be formed rapidly by changing the nutrient solution formula appropriately.Researches for the growth of citrus under the nutrient deficiency conditions are universal,but for the morphology are few. So,we investigate physiological and biochemistry index of the citrus aurtantium seedlings growing in the nutrient solution with different dissolved oxygen concentrations,in order to find out the effect caused by the dissolved oxygen to the growth of citrus aurtantium.We also investigate the root morphology index of the seedlings under the nitrogen-deficiency and iron-deficiency nutrient solution. The main results show that:1 Optimization of a hydroponic culture system for citrus(1)Effect of different dissolved oxygen concentrations on growth of the seedlingsCompared to the citrus seedlings with no air aeration to the nutrient solution(control), the height of the plants of the different aeration treatments increases by the time,and the height of T1 increases considerably in the late period.The growth of leaf area of the plants with different aeration treatments enhances slowly in the first 8 weeks,from the 8th to 12th week it enhances significantly.The leaf area of T1 has significant increase during the experiment,from 4.395cm2 to 60.383 cm2.The fresh and dry weight of the plants with different aeration treatments increases slowly in the previous period, the seedlings grow faster and the accumulation of dry matter was significantly increases in the late period(2)Effect of different dissolved oxygen concentrations on physiological and biochemistry indexCompared to control,relative electronical conductivity of the treatments with different aeration is significantly lower,Tland T2 have a lesser extent in the relative electronical conductivity,but the values of T3 and T4 are higher.Content of MDA increases gradually from T1 to T4,because of the decrease frequency of aeration,as a result,oxygen can inhibit the production of MDA and increase the vigor of the plant eith anti-aging.Values of the root activity of the different aeration treatments are all higher than CK dealed with the same number of days.The values of the root activity of T1 and T2 have no significant defference.Content of soluble protein basically has no change in Tl,changes of T2 to T4 are also not significant,they all in a certain range.The peak of soluble sugar content in T1,T2,T3 all appear 8 weeks after treatment,with an increase of 42.65%,61.10% and 70.61% compared with it before the treatment respectively.Tl maintains high levels of photosynthetic pigment content between the different aeration treatments. The maximum values of Chlorophyll a, total chlorophyll and carotenoid content in T1 appear 8 weeks after treatment, the photosynthetic pigment content of T2,T3,T4 changed little, fluctuating within a certain range.2 Study on root morphology response to nitrogen-deficiency and iron-deficiency of Poncirus seedlings(1)Effect of nitrogen-deficiency and iron-deficiency on growth of the seedlingsCompared to the citrus seedlings growing in the full nutrient solution(control),height of the nitrogen-deficiency and iron-deficiency plant is only 16.4cm and 27.6cm,while the height of control is 44.0cm. Plant leaf area of control were significantly higher than those of nitrogen deficiency and iron-deficiency plant.Dry matter accumulation of nitrogen-deficiency plants are significantly lower than control,the biomass of iron-deficiency plant is between the control and nitrogen treatments.(2) Effect of nitrogen-deficiency and iron-deficiency on root morphology of the seedlingsMain root diameter of nitrogen-deficiency and iron-deficiency plants decrease slightly,there is no difference of lateral root average diameter in all treatments and control, nitrogen-deficiency plant has significantly larger root volume.Main root length and total root length of nitrogen-deficiency plants increases with significantly reduced the number of lateral roots. iron-deficiency plant has the largest main root length,but the total root length was inhubited and the number of its lateral roots reduced significantly.Root activity of nitrogen-deficiency and iron-deficiency plants decreases significantly, nitrogen-deficiency plants have the larger root surface area than control,but decline has been observed in iron-deficiency plants.(3)Effect of nitrogen-deficiency and iron-deficiency on nutrient content of the seedlingsContent of N and P of nitrogen-deficiency plants is all lower in roots,stems and leaves.Only the content of N of iron-deficiency plants in root is less than control, K concentrations of nitrogen-deficiency and iron-deficiency plants in root are significantly lower than control,with little difference in stems and leaves.Content of Fe of iron-deficiency plants in root is significantly lower than that of control and nitrogen treatment,but little difference is observed in stems and leaves.Content of Ca and Mg does not change in all treatments and control,indicating that there is little effect on absorption of Ca and Mg in those both nutrient deficiency.更多还原