聖誕紅氮素營養與氮肥診斷之研究

The Study of Nutrition and Diagnosis of Nitrogen in Euphorbia pulcherrima Willd.

黃校翊(Siao-Yi Huang)

指導教授 ： 張育森

國立臺灣大學/生物資源暨農學院/園藝學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.02333

摘要

本試驗探討聖誕紅（Euphorbia pulcherrima Willd.）‘Peter Star’與‘Red Velvet’於氮肥施用後對生長的影響，以及不同施肥方式或不同營養狀態之植株於施肥後各葉片葉綠素計讀值之變化，並評估不同氮肥診斷方法之可行性。
首先兩品種分別施用了四種氮肥濃度（8、16、24、32 mM）以及對照組(0 mM)。可發現兩品種葉片之氮含量皆隨著氮肥濃度增加而上升，並呈現直線之相關性，以取樣葉片飽和乾重下降10%之氮含量訂定為氮素臨界，則其臨界值‘Peter Star’為2.85%（w/w）而‘Red Velvet’為3.13%。兩品種葉片之硝酸態氮含量則至24 mM處理開始便迅速蓄積。於氮肥處理大多之調查項目（如葉面積、葉乾重等）皆隨著氮肥濃度提升而增加，但是大部分生長量指標至16mM 處理之後差異便不顯著，因此16mM應可滿足聖誕紅氮肥之需求。兩品種生長量的表現，除了‘Peter Star’的葉面積較‘Red Velvet’大之外，其餘生長量幾乎無顯著之差異。
植株不同施肥方式（肥灌、葉片施肥與尿素葉片施肥）處理後其讀值較對照組皆有明顯的上升。於處理間以葉片施肥之葉綠素計讀值反應較早（2 天），但以肥灌處理所增加的讀值較多（7-8個讀值）。於尿素處理後，‘Peter Star’之讀值也有明顯提升；但於‘Red Velvet’的讀值則於施肥前後無顯著差異。對於肥料處理之反應，‘Peter Star’以第一片展開葉、‘Red Velvet’以第二片展開葉為最早，而較成熟的展開葉則反應較慢或無反應。試驗前缺肥之植株於施肥後所增加的葉綠素計讀值較正常供肥之植株為高；且葉綠素計讀值提升的時間也較早。另外，無論植株處於缺肥或正常之營養狀態，於施肥後其讀值上升的時間，‘Red Velvet’均較‘Peter Star’來得較早。
聖誕紅經不同氮肥濃度處理後，顯示兩品種之葉綠素計讀值與葉片氮含量成顯著之直線相關（‘Peter Star’之R2=0.937, n=30；‘Red Velvet’之R2=0.822, n=30），以氮素臨界值分別對應至葉綠素計讀值，則‘Peter Star’為24.0；而‘Red Velvet’為35.2。另外探討比色法應用於氮素診斷之可行性，‘Red Velvet’未施肥之對照組的CMR2/1（第2片展開葉之CMR與第1片展開葉之CMR之比值），於第3-5週開始有小於1的情形發生，而CMR4/2（第4片展開葉之CMR與第2片展開葉之CMR之比值）則於第7週時比值才小於1；‘Peter Star’未施肥之對照組的CMR2/1則於第6-7週時開始有小於1的情況發生。因此認為CMR2/1比CMR4/2有較高之診斷能力，並且‘Red Velvet’較‘Peter Star’適用於比色法。
最後評估葉片之硝酸態氮含量或葉綠素螢光（Fv/Fm）與葉片氮含量之相關性。兩品種之硝酸態氮含量與葉片氮含量具有二次關係，判定係數分別‘Peter Star’為R2=0.715, n=30、而‘Red Velvet’為R2=0.623, n=22，其結果可分為兩群，可是兩品種於葉片氮含量低於3%時，其葉片硝酸態氮含量皆相當低，因此無法正確辨別氮素缺乏時的情形，然而當氮肥充足時硝酸態氮含量呈現迅速累積現象，故應可利用葉片硝酸態氮含量辨別氮肥充足或過量時之狀況。葉綠素螢光與兩品種的葉片氮含量之間亦呈現二次關係，判定係數分別‘Peter Star’為R2=0.586, n=28、而Red Velvet’為R2=0.530, n=26，可是其相關性較低，因此其診斷能力可能較其他診測方法皆來得差，其結果亦可分為兩群，但缺氮植株的Fv/Fm則明顯表現較低，故葉綠素螢光應可應用於聖誕紅氮肥缺乏時之診斷。

關鍵字

聖誕紅 ； 氮素 ； 葉綠素計讀值 ； 硝酸態氮含量 ； 葉綠素螢光

並列摘要

The objective of this study was to (1) investigate the effect of nitrogen (N) fertilizer rate on vegetable growth, (2) measure the effect of different N application methods and plant nutrition conditions on the variations of leaf chlorophyll meter readings (CMR), (3) evaluate the potential of diagnosing methods for predicting N fertilizer requirements in poinsettia（Euphorbia pulcherrima Willd） ‘Peter Star’ and ‘Red Velvet’.
Tow cultivars were applied four N fertilizer rates (8、16、24、32 mM) and control (0 mM). The results indicated that leaf N content was increased continuously with N fertilizer rates, and revealed a linear correlation between N fertilizer rate and leaf N content. Estimated critical N level, which were based on the point that leaf dry weight 10% less than the maximum, were 2.85%（w/w） and 3.13% for ‘Peter Star’ and ‘Red Velvet’ respectively. Leaf nitrate content rapid accumulated at 24 mM N treatment in two cultivars. After N fertilizer application, most growth parameters (leaf area, leaf dry weight etc.) significantly increased, but those were no significantly different among 16 to 32 mM N fertilization treatments. Therefore, 16 mM N fertilization should be a reasonable N rate in poinsettia. Tow cultivars showed similar growth performances, except the leaf area of ‘Peter Star’ was larger than that of ‘Red Velvet’.
After treatments of N application methods (fertigation, foliar spraying and urea foliar treatment), the CMRs of fertilized plants were higher than those of the control plants. For CMR variations, the plants treated with foliar spraying responded earlier than those treated with other methods, but the plants treated with fertigation had higher CMR values. The CMRs of the plants treated with urea foliar treatment increased significantly in ‘Peter Star’, but not in ‘Red Velvet’. After N fertilizer application, the 1st fully expanded leaf of ‘Peter Star’ and the 2nd fully expanded leaf of ‘Red Velvet’ responded to fertilization earlier than the other leaves. The CMRs of plants under nutrition stress increased higher and earlier than those under regular fertilization. In addition, regardless of plant nutrition conditions, the CMR of ‘Red Velvet’ responded earlier than that of ‘Peter Star’.
After poinsettia was applied at different N fertilization rate, there was a significantly positive linear correlation between CMR and leaf N content (‘Peter Star’ R2=0.937, n=30; and ‘Red Velvet’ R2=0.822, n=30), the critical levels of CMR, based on the critical levels of leaf N content, were 24.0 and 35.2 in ‘Peter Star’ and ‘Red Velvet’ respectively. In addition, the CMR2/1 ratio (The CMR of 2nd fully expanded leaf /The CMR of 1st fully expanded leaf) of ‘Red Velvet’ control plant was less than 1 in 3 to 5weeks and CMR4/2 (The CMR of 4th fully expanded leaf /The CMR of 2nd fully expanded leaf) was less than 1 in 7 week. However, only the CMR2/1 ratio of ‘Peter Star’ control plants was less than 1 in 6 to 7 weeks. Therefore, the diagnosing ability of CMR2/1 is better than that of CMR4/2, and this diagnosing methods is more suitable for ‘Red Velvet’.
Finally, we evaluate the relationship between leaf nitrate content or chlorophyll fluorescence（Fv/Fm）and leaf N content. There were positive correlation between leaf nitrate content and leaf N content in two cultivars（‘Peter Star’ R2=0.715, n=30; and ‘Red Velvet’ R2=0.623, n=22）. The data of nirate was divided into two groups. But leaf nitrate content was still at low status when leaf N content lower than 3%, and experiment result was partitioned into two groups (N status wasn’t enough and N status enough), however the leaf nitrate content accumulated rapidly when enough N fertilization. So leaf nitrate content should be an index to determining whether the N status enough or over in poinsettia. There were positive correlation between chlorophyll fluorescence and leaf N content (‘Peter Star’ R2=0.586, n=28; and ‘Red Velvet’ R2=0.530, n=26). The R2 value of chlorophyll fluorescence is lower than that of other indexes. Therefore the diagnosing ability of chlorophyll fluorescence should be lower than other methods. The data of Fv/Fm value was divided into two groups. However, the Fv/Fm value is still at low status when the plants under nutrition stress, thus chlorophyll fluorescence could be a valuable tool for diagnosing N deficiently in poinsettia.

並列關鍵字

Euphorbia pulcherrima Willd. ； nitrogen ； chlorophyll meter readings ； nitrate content ； chlorophyll fluorescence

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