升高二氧化碳濃度與水分缺乏對樟樹苗木形質生長及碳水化合物分配的影響

Effects of Rising CO2 Concentration and Water Deficiency on the Morphological Growth and Carbohydrate Partitioning of Cinnamomum camphora Seedlings

本試驗主要探討高濃度二氧化碳與缺水處理對於樟樹（Cinnamomum camphora）苗木形質生長的影響，並進一步探討苗木結構性碳水化合物及非結構性碳水化合物累積和分配。試驗是將苗木栽植於1L的威特缽中，置於一般二氧化碳濃度（380μmol mol^(-1)）及高二氧化碳濃度（800μmol mol^(-1)）生長箱內，每個生長箱中皆有一半的苗木每10天供水一次，另一半則隔天供水。以10天為一收穫週期，收穫後量測葉面積、地上部和地下部乾物重，並分析碳以及碳水化台物含量。結果顯示生長在高二氧化碳濃度下的苗木，其乾物重的累積顯著高於一般二氧化碳濃度，30天後尤其明顯。缺水逆境下，乾物重的累積會被抑制，但是高二氧化碳濃度缺水處理的苗木與一般二氧化碳濃度處理非缺水逆境處理的苗木，乾物重的累積相差不大。另二氧化碳濃度升高時，會造成葉片及根部可溶性醣類濃度增加，缺水逆境則改變澱粉與可溶性醣類的分配，使得非結構性碳水化合物傾向於水解成小分子醣類。 This study investigated how high [CO2] and low water supply impacted the growth and further discussed structural and non-structural carbohydrate accumulation and partition of camphor seedlings (Cinnamomum camphora). The seedlings were planted in a 1L pot and placed in the chambers of 380 and 800μmol mol^(-1) [CO2]. Half of the seedlings in the chamber were watered once every ten days, while the other seedlings were watered every other day. Seedlings were harvested every ten days. We measured the height and diameter to realize the morphological parameter before harvesting, and then measured the leaf area and dry weight of the above and bellow ground of the seedlings. In addition, carbohydrate and carbon content were analyzed as well. The result suggested that biomass of the seedlings which growth in the elevated [CO2] were significantly higher than the seedlings planted in the ambient [CO2] especially the third period. Water stress would inhibit biomass accumulation. Seedlings planted in the elevated [CO2] with water stress and comparison of seedlings that planted in the ambient [CO2] without water stress showed no significantly difference in total dry weight. Elevated [CO2] resulted in increasing soluble sugar content in the leaves and roots. Under water stress, non-structural carbohydrate would hydrolyze into low molecular sugar and decrease the damage of the drought.

This study investigated how high [CO2] and low water supply impacted the growth and further discussed structural and non-structural carbohydrate accumulation and partition of camphor seedlings (Cinnamomum camphora). The seedlings were planted in a 1L pot and placed in the chambers of 380 and 800μmol mol^(-1) [CO2]. Half of the seedlings in the chamber were watered once every ten days, while the other seedlings were watered every other day. Seedlings were harvested every ten days. We measured the height and diameter to realize the morphological parameter before harvesting, and then measured the leaf area and dry weight of the above and bellow ground of the seedlings. In addition, carbohydrate and carbon content were analyzed as well. The result suggested that biomass of the seedlings which growth in the elevated [CO2] were significantly higher than the seedlings planted in the ambient [CO2] especially the third period. Water stress would inhibit biomass accumulation. Seedlings planted in the elevated [CO2] with water stress and comparison of seedlings that planted in the ambient [CO2] without water stress showed no significantly difference in total dry weight. Elevated [CO2] resulted in increasing soluble sugar content in the leaves and roots. Under water stress, non-structural carbohydrate would hydrolyze into low molecular sugar and decrease the damage of the drought.