探討烏心石苗木形態與生理性狀的關係

The relationship between seedling morphologies and physiological traits of Michelia compressa

烏心石苗木自移植至苗床後，苗木間的生長差異即逐漸表現出來，如果苗床的環境條件是相同的，則此種差異乃個體間使然。苗木出栽時的選拔常以外觀形態判斷，這乃是最方便的方法，但苗木的好壞是否就如同外觀所見？本試驗將230株的烏心石苗木區分為三級後，分別量測各種外觀形態、乾物量及測定每株苗木之葉綠素指數、光合作用與葉片螢光反應，試圖找出以外觀判斷苗木的良莠是否與苗木生理現象吻合？結果顯示各種形態參數（苗高、苗徑、節間數、節間長、 Dickson品質指數等）在三級間均呈極顯著差異。而由乾物量視之，也沒有因為苗高生長較好而導致徒長現象。葉綠素指標、氣孔導度、光合作用及Fv/Fm等在第一、二級間無差異，但均較第三級顯著較高，此些生理指標無法分別第一、二級苗木的差異，因此不能全然解釋苗木品質的優劣。 The growth difference between seedlings gradually manifested after they were transplanted to nursery. If environmental conditions were the same, then such differences resulted from individuals. The seedling morphology usually was the fi rst standard and convenient to judge if the seedlings could be planted in the fi eld. But whether the quality of seedlings could look from morphology? This study divided 230 seedlings of Michelia compressa into three levels, and then planted in the nursery. After 6 months later, to measured the morphological and physiological characters of seedlings, including height, basal diameter, numbers of node, internode length, dry biomass, chlorophyll index, photosynthesis and leaf fl uorescence reaction. This experiment tried to figure out the relationship between morphology and physiology of seedling from the above results. The morphological parameters (height, basal diameter, numbers of node, internode length, Dickson quality index) showed significant difference among the three seedling levels. In terms of biomass, although the first seedling level had higher height, but not resulted in excessive growth. There was no significant difference between the first and second level seedlings in chlorophyll index, stomatal conductance, photosynthesis and Fv/Fm, but higher than the third seedlings. The difference between the fi rst and second level seedlings unable to get from those physiological parameters, indicating the quality of seedlings could not only look from morphological characters.