【作者】 周永祥；

【导师】 黄建国；

【作者基本信息】 西南农业大学 ， 植物营养学， 2002， 硕士

【摘要】 桉树具有生长快，适应性强，用途广，经济价值高等特点。我国种植桉树的面积大，但桉树木材的生产量低。因此，通过合理施肥和接种有效的外生菌根真菌大有潜力提高桉树的木材产量。作者于2001.3至2002.2在西南农业大学校区实验农场以直杆蓝桉为材料，比较系统的研究了其营养特性，包括N、P、K、Ca、Mg、S的含量分布、季节变化以及土壤条件和外生菌根真菌感染对直杆蓝桉生长和养分吸收的影响。目的是为栽培种植直杆蓝桉和合理施肥提供理论依据。试验的供试土壤为紫色土和黄壤，分别设不接种和接种外生菌根真菌两个处理，四次重复，相间排列。结果表明： 1直杆蓝桉不同方位叶片的N、K含量变化趋势较为一致：南>东>西>北，但差异不显著，其它四种营养元素含量在各方位之间的差异也不显著，且变化趋势不一致。 2．直杆蓝桉叶片N、P、K这三种可移动元素的季节变动模式基本一致，都是生长季节初(3、4月)含量最高，随季节而下降，至季末又开始回升，呈现下降—上升的变化模式。叶片Ca含量在旺盛生长的夏季(4-7月)显著高于其它各月，与月均温呈显著正相关(r=0.599，p<0.05)。直杆蓝桉叶片Mg含量变化趋势则与K、Ca相反，3-8月份含量明显低于其它月份，变化幅度较小。直杆蓝桉叶片S含量变化与Mg相似，变化幅度稍大。对叶片各元素含量月变化的相关分析表明，NP、NK、PK都呈极显著性正相关，相关系数分别为0.886、0.922和0.809(p<0.01)，这表明直杆蓝桉在吸收和积累N、P、K的方式是一致的。直杆蓝桉叶片K和Ca呈显著性正相关(r=0.603，p<0.05)，而叶片K和Mg呈极显著性负相关(r=-0.768，p<0.01)。直杆蓝桉叶片Mg和S呈极显著性正相关(r＝0.692，p<0.01)，N和S呈一定负相关但相关关系不显著(r=-0.549，p>0.05)。 3．各器官营养元素含量的季节动态：枝、干、干皮和根系中的营养元素含量有明显的季节动态。枝条中各营养元素含量的季节动态与叶的基本一致；干皮中的N、P、K的季节变化较为一致，3月份含量最高，9月份含量最低。Ca在生长季节(6月)有所上升。Mg、S的变化趋势较为一致，冬春季含量高于夏秋季；树干中N、P、Mg、S含量都比较低，且变化幅度不大，K、Ca相对而言在树干内是比较高的，6月份含量高于其它各月；侧根中各营养元素含量高于主根，二者变化趋势较为一致，在生长季节(6月)中N、P、K含量都高于其它月份，9月 直杆蓝枝公养特性的U乃c根系中三种元素含量都有所下降，12月份有开始回升。Mg、S的变化趋势则呈另一种模式，夏季根中含量显著低于其它各季，9月含量最高。4．各器宜营养元素含量以平均值计的分布规律为：N：n！”（9．44mde单位下同）＞枝条（2．74）＞干皮（2．56p侧根（．12p主根（．59p树干（0．44）；P：干皮（1．16）＞叶（l．14p枝条（．09p恻根（0．85）＞主根（0．45p树干（0．37）；K：OD“（7．30p枝条O．68）＞侧根O．04p干皮（．81）＞主根（2．47p树干（1厂】）；＊a：干皮（21．30P叶（KJ4P侧根（】2．05）＞树干（ic．85）＞枝条（】o．43P主根（吕90）；＊g：为干皮（4二7P叶（3．78P侧根（3．59）＞主根厂jSP枝剥0．7刀＞树干（o．4叮；s：叶（2．31）＞干皮（1刀lp侧根（9】）、枝条N．91）＞主根（．引p树干N．22）。各营养元素在器官中含量的大小顺序为：叶：＊t＊＞K＞＊g＞》P，枝汇少＊＞＊＞卜8＞呐，干皮：＊矽＊g＞＊＞＊＞Ps，树干：C＞卜＊旷N＞P＞s，主根：C＞ K＞NK＞N＞＊旷s＞P，侧根：C＞＊矿K＞ N＞s＞P。S．在不同立地条件下，除Ca外叶片元素含量规律均与土壤一致。可见直杆蓝枝吸收大部分元素数量的高低取决于生长的立地条件。较好的立地条件相对生长较好，养分吸收较多。6．接种菌根菌直杆蓝按各组分营养元素含量与对照处理（不接种）均有差异。按种菌根菌后各组分N含量均高于对照组高，叶、枝条、干皮、树干、主根和侧根分别高出对照组！0．0％、14．3％、19石％、6．7％、34．7％和40．4％。t检验表明，除树干外，菌根苗含N量与对照组差异均达显著水平（p＜0．05），其中根含N量达极显著性水平（p＜0．of）；接种菌根真菌后，树叶、枝条、干皮、树干、主根、侧根中P含量分别高出对照组63．5％、50％、40．3％、34．2％、71．l％和 71．2％，差异达极显著水平（p＜0．01）；接种菌根苗木的叶、枝条、干皮、树干各组分K含量较对照组均有所降低，降低的百分数分别为：2二％、4．l％、1．3％和 1．9％，但差异不显著。主根、侧根中K的含量较对照组分别高出38．5％，14．4％，差异显著（V叱．05）。表现为促进K在地下部分（根系）中的积累却减少了在地上部分的积累；对Ca的影响，表现为抑制Ca素在植株中的积累，叶、枝条、干皮、树干、主根、侧根分别较对照组下降了36．8％、40．2％、1．0％、41．5％、12．2％和 30．0％，除干皮外，差异均达显著水平（p＝（．05h对 gg的影响，地上部分差异不明显，主根和侧根中 Mg的含量分别高出 38．8％和 17．9％，差异显著；接种菌根菌对苗木各器官S含量的影响不大，且规律?更多还原

【Abstract】 Eucalyptus with the abilities of fast growth and varied adaptation is widely and economically used for multi-purposes. There are large areas grown eucalyptus but with the low lumber production in our country. Therefore, it seems reasonable to promote the growth of eucalyptus trees by rational fertilization and ectomycorrhizal fungus inoculation. The present experiment was established in the experimental farm of Southwest Agricultural University and the nutrition of eucalyptus trees was studied systematically from 2001.3 to 2002.2 in order to supply the guidance in cultivation and fertilization practices. The growth and nutrient absorption of eucalyptus with and without ectomycorrhizal fungus inoculation were compared in yellow and purplish soils. The arrangement of inoculation - no inoculation was adopted with 4 replications in the experiment. At the same times!, the distribution and seasonal changes of macronutrients (N, P, K, Ca, Mg and S) were recorded in eucalyptus trees. Following are the results obtained:1. Similar changes and important differences of N and K in the leaves of eucalyptus in different directions were found in accordance with South, east, west, north, even though there were no significant variations in directions. For other four elements (Ca, Mg, S and P) in the leaves, however, rose and fell little in directions yet if any.2. Similar evolution of N, P and K, the movable elements in trees, were observed in the leaves of eucalyptus. The contents of the three elements had a pattern of decrease-increase which reached the peak in the early growing period (March or April) and decreased with seasons and then increase in the later period. The concentrations of Ca in the leaves were remarkably higher in summer (from April to July), the fast growing period, than those in any other months. Positive correlation (r=0.599,p<0.05) was detected between the contents of Ca and monthly average temperatures. The variations of Mg in the leaves of eucalyptus, however, tended to be opposite to those of K and Ca. Obviously low Mg concentration were observed from March to August and varied very little each month if any. S in the leaves fluctuated similarly but largely compared to Mg. Significant correlations were established between N and P (r=0.886,p<0.01), N and K (r=0.922,p<0.01), P and K (r=0.808,p<0.01), indicating similar absorption and accumulation of N, P and K by eucalyptus trees. Moreover, The contentsbetween K and Ca(r=0.630,p<0.05), and between Mg and S (r=0.629,p<0.05) correlated positively in the leaves, while negatively between K and Mg (r= -0.678,p<0.01), and not significantly between N and S (r= -0.549,pX).05).3. There was a significant seasonal change in the contents of nutrient elements in branches, stems, barks and roots. The seasonal dynamic changes of all elements in branches were similar to those in leaves. The N, P, and K seasonal dynamic patterns showed similar in barks, i.e. highest in March and lowestin September. The Ca content in barks was highest in June while Mg and S concentrations in warmer seasons were lower than those in colder seasons. Very lower level of N, P, Mg, and S in the trunks were detected and changed very little among seasons while the relatively higher level of the K and Ca reached the peak in June. At the same time, the element concentrations in side roots were higher than that in main roots and the seasonal variations were similar, which were highest in June and fell in September and rose in December. However, the seasonal changes of Mg and S in the roots tended to another pattern of which were lowest in June and highest in September.4. Generally speaking, the average nutrient contents (mg/g) in various organs in .the Eucalyptus Maideni F.Muell were in the following orders. N: leaves(9.44)> branches(2.74)> barks(2.56)> side roots(2.12)> main roots(1.59)> trunks(0.44), P: barks(1.16)> leaves(1.14)> branches(1.09)> side roots(0.85)> main roots(0.45)> trunks(0.37), K: leaves(7.30)> branches(4.68)> side roots(3.04)> barks(2.81)> main roots(2.47)> tru更多还原