馬拉巴栗小品盆栽生產技術之改進

Produce Improvement of Cultural Techniques in miniature potted Malabar chestnut (Pachira macrocarpa)

彭永良(Yung-Liang Peng)

指導教授 ： 張育森

國立臺灣大學/生物資源暨農學院/園藝暨景觀學系/博士(2015年)

https://doi.org/10.6342/NTU.2015.00419

摘要

馬拉巴栗為台灣重要景觀盆栽之一，為改進其栽培模式，進而加速生長，提升品質，提高國際競爭力，更顯得重要。本論文分成幾個項目，首先為氮肥管理及營養診斷，水分管理及非破壞性量測，進而探討光質對其生長之影響以及最適栽培溫度，期能建立高效能之現代化生產體系。
本研究探討不同氮濃度對其生長之影響，結果顯示，馬拉巴栗小苗於每週施與濃度0、4、8、16及24 mM氮肥，12週後各生長參數如株高，節數和葉面積於16mM皆達最高。另外，由葉綠素計讀值，葉片中葉綠素濃度及氮濃度，葉乾重皆得知16 mM為氮肥最佳施用濃度。葉綠素計可用來非破壞性監控植物達最佳生長所需氮肥。本研究於制訂氮肥臨界濃度時發現，葉綠素計讀值達46.1時，葉片中氮濃度為2.65%，此時葉片乾重為飽和乾重之90%，將此定為氮肥臨界濃度。超越該臨界濃度所施用氮肥可增加葉片葉綠素含量及淨光合作用速率。因此，葉綠素計具方便和非破壞性之優點，可提供商業生產馬拉巴栗於監控其氮肥需求時可靠參考。本研究建議每週施與馬拉巴栗16 mM 氮肥並將葉綠素計讀值維持於46.1和58.4間。此外，不同氮肥濃度間，葉片光譜反射分布規律呈現一致的趨勢，綠光區(560-570 nm)和紅邊區(red edge) (690-760 nm)是葉綠素的強烈反射波段，出現了反射峰值，隨著施氮量的變化，在反射強度上有所差別，可以此作為施肥量的依據。單一波長與氮素含量之間的關聯，從可見光譜區域至近紅外光譜區域發生大幅的改變，氮含量與反射率呈現高度負相關性，特別是在綠光區域(510-550 nm)及紅邊區域 (690-740 nm)表示這些波段範圍具有高度相關性。各類植生指數以MTCI指數的相關性最高，其R2=0.98。本研究成果能即迅速反應葉片中氮含量的即時狀態，更能精準的建立馬拉巴栗氮素營養診斷。
為探討水分對馬拉巴栗生長之影響，將其處理不同的限水天數，結果顯示，馬拉巴栗隨著限水天數增加，莖徑、土壤水份、葉綠素螢光等量測值皆有下降的趨勢，但葉綠素螢光的潛值差異不明顯。光譜測值與莖幹水分具有趨勢性，單一波段以1450 nm及1650 nm較高，植生指數以WBI(R900/R970)較高。除此之外，比較不同季節生產的馬拉巴栗莖幹含水量，夏季生產者莖幹平均含水量為81.8%；而秋季生產者莖幹平均含水量為66.44%，以植生指數WBI(R900/R970)光譜量測與莖幹含水量其相關性R2=0.62。
利用發光二極體(LED)作為人工光源，探討光質對馬拉巴栗綠苗編栽培生產之影響。試驗結果顯示：單純提供紅光具有延長馬拉巴栗上胚軸長度及促進地徑膨大的效果;而單純藍光則對延長下胚軸長度及發根數效果較顯著；白光及遮陰處理的葉綠素計讀值較高；由上述結果得知：人工光源可應用於生產高品質馬拉巴栗綠苗編。
在溫度方面，本研究利用不同的栽培溫度處理(日夜溫35/30℃、30/25℃、25/20℃、20/15℃及15/13℃)，探討溫度對馬拉巴栗種子萌芽及不同苗期生長之影響，結果顯示：各溫度處理下，種子發芽率皆可達100%，然隨著溫度的提高，有助於加快種子萌芽速度；播種一個月後觀察，在日夜溫20/15℃及15/13℃處理下，株高及節數明顯受到抑制，莖徑在15/13℃處理下有明顯加粗的表現。若在同一溫度下(約20-25℃)育苗後再移入不同溫度處理，其結果顯示：日夜溫25/20℃下生長，莖徑、葉面積、葉綠素計讀值、地上部及地下部乾重均表現較高，其次為30/25℃，而35/30℃處理下生長表現較差；20/15℃處理下有輕微寒害發生，15/13℃處理下，葉面積縮小，葉色濃度變淡、葉綠素螢光的比值也最低、寒害現象也更為嚴重。
綜合言之，每週施與馬拉巴栗16 mM 氮肥，並應用植生指數MTCI，迅速反應葉片中氮含量的即時狀態，更能精準的進行馬拉巴栗氮素營養診斷；非破壞性水分量測以反射光譜1450 nm及1650 nm較高，植生指數以WBI(R900/R970)較高；以LED藍光可延長下胚軸長度及發根數；馬拉巴栗較適宜生長的溫度範圍約在20-30℃之間。

關鍵字

馬拉巴栗

並列摘要

Malabar chestnut is an essential nursery crop and ornamental potted plant in Taiwan. Cultivation improvement for accelerating plant growth and enhancing product quality is important. This study is divided into two parts. The first part includes the nitrogen fertilization management, the diagnosis of plant nutritional status, irrigation management and non-destructive measurements. The second part discusses the effect of light quality on plant growth and the optimum cultivation temperature. We expect these investigations may be applied for modern production system in the future. Malabar chestnut seedlings were fertilized weekly with 0, 4, 8, 16, or 24 mM N. After 12 weeks, 16 mM N was found to yield the greatest plant growth such as plant height, number of nodes, and total leaf area. Measurements of chlorophyll meter readings, leaf chlorophyll concentration, leaf N concentration, and leaf dry weight all indicated that the optimal level of N fertilization was 16 mM N. A chlorophyll meter can be used to monitor non-destructively whether sufficient N has been supplied to support optimal plant growth. In this study, a chlorophyll meter reading of 46.1 corresponded with a critical leaf N concentration of 2.65%, defined as the leaf N concentration when the leaf dry weight was at 90% of saturation point. Additional N supplied beyond this critical level increased foliar chlorophyll content and improved the rate of net photosynthesis. Therefore, chlorophyll meter readings which are convenient and non-destructive can serve as a reliable reference for commercial production in monitoring N requirement for optimum growth of malabar chestnut. Weekly fertilization of malabar chestnut with 16 mM N and maintaining leaf chlorophyll meter readings between 46.1 and 58.4 are recommended.
The results revealed that the foliage spectral reflectance distribution patterns of the various nitrogen concentrations were identical. The green-light waveband (560–570 nm) and red edge (690–760 nm) are strongly reflected by chlorophyll. The reflectance peak value varied based on nitrogen application rate. Variation in reflectance strength can be used to determine the amount of fertilizer that should be used. The relationship between single wavelengths and nitrogen concentration revealed a drastic change in the visible-light and near-infrared spectrums. Nitrogen concentration and reflectance were highly negatively correlated, particularly in the green-light region (510–550 nm) and on the red edge (690–740 nm), indicating that these wavebands were highly correlated. Among the various vegetation indices, the medium resolution imaging spectrometer terrestrial chlorophyll index exhibited the highest correlation (R2 = 0.98). The results can be used to immediately determine the real-time status of foliage nitrogen concentration and precisely diagnose nitrogen nutrition in malabar chestnuts.
Spectral measurements yielded the same trend. In a single reflectance spectrum, 1450 nm and 1650 nm demonstrate the highest correlation in water content. Comparing the stem water content of malabar chestnut production in different seasons yielded an average water content of 81.8% in the summer and 66.44% in the autumn.
The effect of light quality during the production of young malabar chestnut plants for braiding was investigated by growing them under LED lights. Illumination with only red light increased epicotyl length and collar diameter. Illumination with just blue light increased hypocotyl length and the number of roots. The use of white light and shading resulted in higher chlorophyll meter readings. Therefore artificial light sources can be used to produce high quality young plants for braiding.
This study also investigated the effects of different temperatures (day/night 35/30℃, 30/25℃, 25/20℃, 20/15℃, and 15/13℃) on seed germination and growth stages of malabar chestnut. Our results showed that 100% germination rate was reached under all temperature treatments and that increasing temperature was conducive to accelerated seed germination. Plant height and number of nodes were visibly inhibited with day/night temperatures 20/15℃ and 15/13℃ one month after sowing, but stem diameter was noticeably thicker under 15/13℃ treatment. When seedlings were grown under similar temperatures initially and then subjected to different temperature treatments, day/night 25/20℃ resulted in the greatest increase in growth, stem diameter, leaf area, chlorophyll meter readings as well as dry weights for shoots and roots; 30/25℃ produced intermediate results while 35/30℃ resulted in relatively poor growth. The plant developed minor chilling injury under 20/15℃. Treatment with 15/13℃ resulted in reduced leaf area, faded foliar color, lower chlorophyll meter readings and more severe chilling injury. In summary, temperature ranges within 20-30℃ are most favorable for the growth of malabar chestnut.

並列關鍵字

Malabar chestnut

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