根溫對火鶴花盆花生長之影響

Abstract

火鶴花 (Anthurium andraeanum Hort.) 為花燭屬 (Anthurium) 之多年生草本花卉，火鶴花是優良的居家及室內植物，在臺灣市場極具發展潛力。臺灣於冬季栽培火鶴花常遭遇氣溫過低導致植株生長及產量下降之問題，若提升氣溫則大幅增加生產成本；於夏季栽培火鶴花則面臨氣溫過高之不利環境。於冬季時提高根溫及夏季時降低根溫可能抵銷過高及過低氣溫之負面影響，本試驗期望瞭解火鶴花之合理根溫範圍，供火鶴花盆花栽培之參考。 冬春季平均氣溫19℃環境下，給予火鶴花盆花小苗18、21及24℃三種根溫處理，以21及24℃根溫處理者於處理5-24天後之光系統II最大效率顯著較根溫18 ℃處理者高。根溫18℃處理之葉綠素計讀值顯著較低，而提高根溫至24℃可顯著減少黃化/壞疽葉片數。處理120天後，根溫21℃處理者有最大之全株乾重、地上部乾重及根乾重。 冬季平均氣溫21℃時給予火鶴花盆花17、21、25、31及38℃五種根溫處理，根溫自25℃提高至32及38℃導致葉片數及葉面積顯著下降，同時亦造成淨光合作用速率及氣孔導度顯著下降，根溫38℃更造成葉片顯著黃化。根溫17 及21℃處理之全株乾重最高，而根溫38℃處理者最低。根溫17、21及25℃處理之地上部乾重差異不顯著，根溫自25℃提高至31及38℃造成地上部乾重顯著下降，根乾重之變化趨勢與全株乾重類似。 於春季平均氣溫19℃時給予火鶴花盆花20、24及32℃等三種根溫處理，處理後14天內，不同根溫處理間之光系統II最大效率差異並不顯著，且Fv/Fm均維持在0.7-0.8之間。根溫20及24℃處理間之淨光合作用速率無顯著差異，而根溫32℃處理造成淨光合作用速率顯著下降至接近0。根溫提高至32℃造成黃化/壞疽葉片數增加、葉綠素計讀值及葉面積顯著下降。根溫20及24℃處理間之地上部乾重無顯著差異，而根溫32℃造成全株乾重及根乾重顯著下降。根溫32℃處理造成地上部及根部之氮、磷及鉀濃度顯著下降，也導致全株之氮、磷、鉀、鈣及鎂等元素含量顯著下降。 於春夏季時將火鶴花盆花移入平均氣溫21℃之生長箱，並給予15、20、21、24及28℃等五種根溫處理。處理後13天間之光系統II最大效率於處理間無顯著差異。根溫自15℃提高至20℃可顯著提高淨光合作用速率及氣孔導度，而根溫自24 ℃提高至28℃導致淨光合作用速率及氣孔導度下降。根溫自15℃提高至20℃可顯著增加葉片數、葉面積及花朵數，但根溫提高至28℃導致葉片數及葉面積顯著下降。根溫處理92天後，根溫20℃處理者之全株乾重、地上部乾重及根乾重較15及28 ℃處理者高。根溫15及20℃根溫處理在第39-53天其根部丙二醛含量上升，而根溫21、24及28℃處理其根部丙二醛含量下降。根溫28℃處理者於處理39天時丙二醛含量顯著高於其他處理，處理間以20℃處理者較低。根溫15及20℃處理者之處理53天之丙二醛含量較處理39天時有增加之趨勢，處理間以根溫24℃處理者較低。

Anthurium andraeanum Hort. is a perennial herbaceous plant suitable for indoor plantscape. In Taiwan, Anthuriums are produced year-round under shade houses without temperature controlled. Low temperatures during winter result in slow growth and lower yield. Heating is not practical under shadehouses and increase production cost significantly. On the other hand, high temperatures during summer would reduce growth. In practical, adjusting root-zone temperature would be an alternative to enhance plant growth. This study was to determine the optimal temperature range of potted Anthurium ‘True Love’ in sand or hydroponics system. During winter to spring at air temperatures of 13-29℃, young plants of Anthurium ‘True Love’ were treated with root temperatures 18 (unheated), 21 and 24℃ for 120 days. At 5 to 24 days after treatments, Fv/Fm value (maximum photosystemII efficiency) was higher in plants with 21 and 24℃than unheated treatment. Plants grown without heating had lower SPAD values. Bottom heating at 21 or 24℃ could reduce number of chlorotic and necrotic leaves. At 120 days after treatments, plants at 21℃ had higher plant dry weight than those at 18 and 24℃ treatments. During winter at air temperature of 18-29℃, plants were grown with root temperatures of 17 (unheated), 21, 25, 31, and 38℃. Leaf number, leaf area, net photosynthesis rate, and stomatal conductance were lower when root temperature increased to 31-38℃. Leaf yellowing appeared in plants grown at 38℃. Whole plant dry weight was the highest when treated with 18 and 21 oC and the lowest in 38℃ treatment. Shoot dry weight decreased when root temperature increased from 25℃ to 31-38℃. Shoot dry weight did not differ in the 17-25℃ treatments. In Expt. 3, plants were grown with root temperatures of 20, 24, and 32℃ at air temperatures of 13-27℃ during spring. Within 14 days after treatments, Fv/Fm value (0.7-0.8) did not differ between treatments. Root temperature of 32℃ significantly reduced net photosynthesis rate. Higher root temperature at 32℃ resulted in significant increase of chlorotic and necrotic leaves and decreases of SPAD value and leaf area. Shoot dry weights in plants of 20 and 24℃ treatment were higher than those grown at 32℃. Root temperature of 32℃ significantly reduced shoot and root nitrogen (N), phosphorus (P), and potassium (K) concentrations and whole plant content of N, P, K, calcium, and magnesium. In Expt. 4, potted plants were grown in hydroponics, with air temperatures of 15-30℃ in a growth chamber during spring. Root temperatures of 15, 20 (control), 21, 24, and 28℃ were set. Within 13 days after treatment, Fv/Fm value did not significantly differ between treatments. Net photosynthesis rate (Pn), stomatal conductance (gs), leaf number, leaf area, and number of flowers increased when root temperature increased from 15 to 20℃. A further increase in root temperature to 28℃ caused significant decrease in Pn, gs, leaf number and leaf area. At 92 days after treatment, plants grown with root temperature 20℃ had higher whole plant, shoot, and root dry weights than those grown with 15 and 28℃. Treatments at 20 and 28℃ had the lowest and highest root malonyldialdehyde (MDA) content at 39 days after treatment, respectively. Plants grown with root temperatures of 15 and 20℃ had higher MDA content at 53 days after treatment (DAT) than at 39 DAT. Root temperature at 24℃ resulted in a lower MDA content at 53 DAT.