【作者】 党瑞红；

【导师】 范海；

【作者基本信息】 山东师范大学 ， 植物学， 2007， 硕士

【摘要】 1.海滨锦葵的抗盐阈值:经0（CK）、10、20、30、40、50、60、70、80 mmol/L NaCl处理发现,40 mmol/L NaCl处理下,海滨锦葵的干重、鲜重、净光合速率（Pn）、潜在光化学效率（Fv/Fm）、实际光化学效率（φPSⅡ）均最高,除Fv/Fm与CK相比变化不明显外,其余各指标均与CK差异显著（P<0.05）。因此海滨锦葵的抗盐阈值大约为40 mmol/L NaCl。2.等渗水分和盐分胁迫对海滨锦葵生长的效应:NaCl和等渗的聚乙二醇（PEG）均引起海滨锦葵生长下降,100 mmol/L NaCl处理使植物含水量及肉质化程度有所提高（P>0.05）,而200 mmol/L NaCl及所有的PEG处理都使海滨锦葵的含水量和肉质化程度明显降低（P<0.05）。NaCl处理下植物体内Na⁺含量增多而K⁺含量下降,但PEG处理均引起Na⁺和K⁺含量同时下降。另外,随NaCl和PEG浓度的增加,海滨锦葵的渗透调节能力升高,NaCl处理下的升高幅度明显大于PEG处理的;处理同时导致叶片Pn、气孔导度（Gs）和Fv/Fm的降低,且等渗PEG的作用较NaCl的作用明显。结果表明PEG对海滨锦葵的影响比NaCl的影响大,即海滨锦葵对盐胁迫的适应能力较强,而对水分胁迫的适应能力较差;在100 mmol/L NaCl处理时,海滨锦葵的Pn变化主要由气孔因素引起,200 mmol/L NaCl和所有的PEG处理时Pn的变化主要由非气孔因素引起。3. NaCl对海滨锦葵生长和生理的效应:在100～300 mmol/L NaCl处理下,海滨锦葵的鲜、干重随着盐处理浓度的升高而下降。100 mmol/L NaCl处理下鲜、干重较CK下降不明显（P>0.05）,随着盐浓度的升高,鲜、干重都明显降低（P<0.05）。海滨锦葵含水量和肉质化程度变化随盐浓度的升高主要呈降低趋势,100 mmol/L NaCl处理较CK略有升高,200、300 mmol/L NaCl处理较CK显著降低。说明较低盐度对海滨锦葵影响不大;也说明海滨锦葵在适应盐渍环境的过程中,未通过稀盐方式抗盐。盐胁迫下海滨锦葵的Pn随处理盐浓度的升高而下降。CK和100 mmol/L NaCl处理下Pn的日变化呈明显的双峰曲线。早晚Pn、Gs较低,胞间二氧化碳浓度（Ci）较高,中间阶段,Pn降低时,Gs下降,同时Ci也降低;200、300 mmol/L NaCl处理Pn变化呈单峰,在Pn增大时,Gs和Ci降低。因此,海滨锦葵Pn的降低在较低盐胁迫下主要是气孔因素作用的结果,在高盐浓度胁迫下主要是非气孔因素作用的结果。早晚时段由于光强弱,温度低,光合相关酶活力低,海滨锦葵Pn较低。强光和高温容易引起光抑制,也可能使PSⅡ活性降低,因此正午海滨锦葵在CK和100 mmol/L NaCl处理时出现光合“午休”现象。200、300 mmol/L NaCl处理未出现光合“午休”现象,可能是交叉适应的结果-海滨锦葵在适应盐胁迫的过程中增加了对高温高光强的适应能力。叶片和根部硝酸还原酶（NR）活性在各处理下的变化趋势有很大差异。随处理盐度升高,叶片NR活力先升高后降低,根部则逐渐降低。与CK相比, NaCl处理下NR活力变化明显（P<0.05）。而N03一含量变化:在叶片中正好与叶片的NR变化方向相反;在根部则与根部的NR变化趋势一致。由此可以得出:在CK下,NO₃^-的同化还原可能主要在根部进行,而在盐处理下,N03一的还原则主要可能在叶片进行。根系的总长度、表面积、总体积、根尖数等参数均随处理盐度的升高而降低。结合TTC的还原强度随处理盐度的增加在100 mmol/L NaCl处理时达到最大值,接着开始降低。可以说明在较低盐分条件下,海滨锦葵需要消耗更多的能量来维持自身正常的生长,300 mmol/L NaCl时海滨锦葵的生长代谢已大幅度降低4.海滨锦葵的拒盐特性:测定海滨锦葵幼苗根部、茎基、茎、叶柄和叶中无机离子（Na⁺、K⁺、Ca2+、Cl-、NO3-）含量,分析其随NaCl处理浓度升高的变化趋势及其在不同处理下不同器官中的分布;分析Na⁺、K⁺动态变化和向地上部分的运输情况。可以得出:海滨锦葵主要通过主要拒Na⁺部位:根部-茎-叶柄的拒Na⁺作用以及主要聚Na⁺部位根、茎、叶柄的Na⁺累积效应,减少盐分向叶片运输,保持叶片较低的Na⁺/K⁺,这种拒Na⁺作用在高盐度下仍维持较高趋势。5.海滨锦葵的渗透势和渗透调节能力:测定分析各处理下叶片和根部无机离子（Na⁺、K⁺、Ca2+、Cl-、NO3-）和可溶性有机物质脯氨酸（Pro）、总游离氨基酸（FAA）、可溶性糖（SS）、有机酸（OA）含量的变化。计算、分析无机离子（Na⁺、K⁺、Ca2+、Cl-、NO3-）和可溶性有机物质对渗透势贡献的大小。结果表明海滨锦葵渗透调节能力随处理盐浓度的升高而增加,渗透调节剂以无机离子为主。更多还原

【Abstract】 1. Salt-tolerance threshold of K. virginicaSeedlings of K. virginica were treated with Hoagland solution containing 0（CK）, 10, 20, 30, 40, 50, 60, 70 and 80mmol/L NaCl respectively. The results showed under 40 mmol/L NaCl, the dry weight, fresh weight, Pn, Fv/Fm andφPSⅡof K. virginica were all the biggest. However, Compared with CK, Fv/Fm was no significantly affected, while the others were different （P<0.05）. This showed the optimum salt- resistance threshold of K. virginica is 40 mmol/L NaCl.2. Effect of iso-osmotic water and salt stress on the growth of K. virginicaThe growth of K. virginica was lowered under the treatment of NaCl and isotonic PEG. The water content and succulent degree of seedlings will be increased under the treatment of 100 mmol/L NaCl （P>0.05）, but the water content and succulent degree of plants were obviously decreased under the treatment of 200 mmol/L NaCl and all concentrations of PEG （P<0.05）. Furthermore, The Na⁺ contents of plants were increased under NaCl treatments, while the K⁺ contents were decreased. However, both of Na⁺ and K⁺ contents decreased significantly under the treatments of PEG. In addition, along with the concentration increase of NaCl and PEG, the osmotic adjustive ability of K. virginica also increased, but the degree of NaCl treatments was higher than that of PEG. Simultaneity, the plasma membrane permeability, net photosynthetic rate （Pn）, stomatal conductance （Gs） and photochemical efficiency （Fv/Fm） all decreased under the treatments, but the effect of isotonic PEG was more serious than NaCl. The results indicated that K. virginica was much more adapted to salt stress, rather than to osmotic stress. In addition, we can conclude stomatal factor was the main reson for Pn under the 100mmol/L NaCl treatment, but the non-stomatal factor dominated under the 200 mmol/L NaCl and both PEG treatments.3. Effect of NaCl on the growth and physiology of K. virginicaUnder the treatment of 100 to 300mmol/L NaCl, the fresh weight and dry weight of K. virginica decreased with the increase of NaCl concentrations However, compared with control, the growth indexes of K. virginica decreased slightly under the treatment of 100 mmol/L NaCl （P>0.05）, and then decreased significantly as the increase of NaCl concentration （above 200 mmol/L NaCl）. Water contents and succulent degree decreased with the increase of NaCl concentration. These indicateed that low concentrations of NaCl only has slightly effect on K. virginica; and salt-dilution does not seem to be the way of salt adaption in K. virginica. Under the treatments of CK and 100 mmol/L NaCl, the daily change of photosynthesis curves displayed two-apices. In the morning and the evening, Pn, Gs were low, but Ci was high; in the other time of the day, Gs and Ci simultaneously decreased when Pn decreased. The daily change of photosynthesis curves displayed single-apice under the treatments of 200 and 300 mmol/L NaCl. We can see Gs and Ci are decreased when Pn increased. So we can conclude stomata factors mainly led to the decrease of Pn under low NaCl treatments, and non-stomata factors prevailed under high NaCl treatments. In the morning and evening, low Pn was results of insufficient illumination, low temperature and low active of correlative enzymes. On the contrary, abundance illumination and higher temperature were easy to lead photoinhibition or the inactivition of PSⅡ, which can explain the midday depression of photosynthesis siesta of K. virginica under the treatments of CK and 100 mmol/L NaCl. There is no midday depression under the treatments of 200 and 300 mmol/L NaCl, which may be the result of cross-adaption, i.e. K. virginica strengthen its ability to adapt insufficient illumination and high temperature in the course of adaptation to salt-stress.NR activities of shoots and roots showed greatly difference under NaCl treatments. With the increase of NaCl concentration, NR activities rose at first, subsequently fall in shoots; however NR activities gradually fall in roots. Compares with CK, NR activities were prominently different under salt treatments （P<0.05）. In addition, the directions of NO3- contents were contrary to NR activities in leaves, but which were coincident to NR activities in roots. These results predicated some probable conclusions that NO3- mainly deoxidized in roots under CK treatments while it did in leaves under the salt-treatments.The total length, surface area, total volume and top tips of roots of K. virginica decreased with the increase of NaCl concentration. The reductive capability of TTC got to the max under the treatments of 100mmol/L NaCl, and then gradually decreased with the increase of NaCl concentration. So we concluded that K. virginica needed more energies to meet growth under lower salt-treatments, in addition, the growth and metabolism greatly decreased under 300 mmol/L NaCl treatments.4. Salt-exclusion characteristic of K. virginicaUnder NaCl treatments, the contents of inorganic ions (Na⁺、K⁺、Ca²⁺、Cl^-、NO₃^-) in the roots、caudexes、stalks、leafstalks and leaves were mensurated and analyzed for their variational trends as well as their distribution in the different organs. Moreover, the dynamic changes of Na⁺ and K⁺ and their transportations to the shoots were analyzed. The data suggested that exclusion of Na⁺ was the main method of salt-adaptation. The roots-stalks-leafstalks system was responds for the storage and exclusion of Na⁺. Through this way less Na⁺ were transported to leaves, which can maintain normal function of leaves. And this has largerer capability under higher NaCl treatments.5. Osmotic potential and osmotic adjustment capabilities of K. virginicaIn the roots and leaves, the contents of inorganic ions (Na⁺、K⁺、Ca²⁺、Cl^-、NO₃^-) as well as soluble organic substances （Pro、FAA、SS、OA） in the leaves and roots were determined. Furthermore, we also calculated and analyzed the role of inorganic ions and soluble organic substances played in osmotic potential. The results showed K. virginica could tolerate salinity by osmotic adjustment, and inorganic ions were dominant osmotic regulators.更多还原