木贼叶木麻黄水分生理之研究-国立中兴大学试验林管理处.DOC

木賊葉木麻黃水分之王經文1、廖天賜2、 【摘要】木賊葉木麻黃今為海岸防風林的重要造林樹種，在強烈的逆境下，呈現易衰退枯萎之象，然以木麻黃為海岸林之第一線樹種仍具不可替代之地位，而海岸沙丘乾旱環境為林木的主要障礙因子之一，故本研究以水分生理為主題，探討適合木賊葉木麻黃苗生長之水分環境。試驗結果顯示，木麻黃苗木對乾旱極具忍耐力，能維持平緩的生長量，且含水率相（70％），而乾物量累積最多達23.12 g苗乾物量累積缺水情況光合作用速率下降，可溶性蛋白逐漸累積，最多30％處理達5.6 mg g-1，滲透潛勢，以利水分之維持。斷水期間，葉片水勢逐漸下降，缺水處理的苗木藉由關閉氣孔來減少水分喪失，分別在第17、21天達到黎明前水勢，並能提高葉黃素循環增加對過多能量的消散，其葉片反射光譜PRI最低降至-0.062，且隨著缺水強度增加對木麻黃苗木之健化效果愈明顯。 【關鍵詞】木賊葉木麻黃、葉片反射光譜、葉綠素螢光、光合作用速率、 葉片水勢1國立中興大學, Department of Forestry, NCHU, Taichung, Taiwan. 2國立中興大學森林系副教授，通信作者 Ass Professor, Department of Forestry, NCHU. Taichung, Taiwan. Corresponding author. 3. 國立中興大學Graduate student, Department of Forestry, NCHU, Taichung, Taiwan. Response of Water Stress on Casuarina equisetifolia Seedlings 【Abstract】Casuarina equisetifolia is the important windbreak species used to planting at the sharp end, it has shown declined because of the foul environment and typhoon stricken continuously. C. equisetifolia had grow hardly. In order to understanding the natural regeneration mechanism of C. equisetifolia, we set various water treatment and observed the responses on phenology and physiology. C. equisetifolia shown the great tolerant during water stress. C. equisetifolia can keep mild growth and maintained the same water content（around 70％）with control in the drought treatment. C. equisetifolia accumulated soluble proteins during drought situation. C. equisetifolia had 5.6 mg g-1 of soluble proteins in water content 30％ treatment, that will probably increase the osmoregulation to absorb water. Seedling in droughty treatment reduced water loss by closing stomata, and enhanced the ability of xanthophyllcycle （minimum PRI ≒ -0.062）, and shown hardened effect by enhanced water stress. 【keywords】Casuarina equisetifoliaspectral reflectance, Chlorophyll fluorescence, photosynthetic rate, leaf water potential 一、前言台灣四面環海，海岸線全長達1,139 km，由於沿海地區常受冬季季風及夏季颱風的嚴重侵襲，而海岸防風林具減低風速、防止風蝕、過濾鹽霧、減少土壤水分蒸發等功能，因此種植海岸防風林對海岸地域之飛砂安定、農作物生產及生活環境的保護極為重要（林信輝，1987）。而第一線之造林樹種多以抗風耐鹽且耐貧瘠之木麻黃為主，其生長快速