5种热带花灌木对旱涝胁迫的生理和形态响应及园林应用

Physiological and Morphological Responses of Five Tropical Flowering Shrubs to Drought and Waterlogging Stress and Their Landscape Utilization

【目的】研究5种热带花灌木在不同水分胁迫处理下生理及形态指标的变化,以揭示植物对旱涝胁迫的响应规律。【方法】以黄蝉(Allemanda schottii)、栀子(Gardenia jasminoides)、斑叶鹅掌藤(Schefflera arboricola‘Variegata’)、钟花蒲桃(Syzygium campanulatum)和狗牙花(Tabernaemontana divaricata)5种热带花灌木为试验材料,对其进行正常供水(CK)、干旱(CD)、水淹(CF)、旱涝交替(FD)4个水分胁迫处理,观察不同水分胁迫处理下植物的形态变化并测定各项生理指标,并用模糊隶属函数法进行植物抗逆性的综合评价。【结果】干旱胁迫下钟花蒲桃叶片受害最严重(VI级),5种花灌木的SOD活性均下降、丙二醛含量均上升,斑叶鹅掌藤叶绿素含量显著下降(P<0.05);淹水胁迫显著影响植物的外部形态,栀子长出新根,黄蝉形成肥大皮孔并长出大量新根和新叶,斑叶鹅掌藤大量叶片萎蔫、根部严重腐烂,狗牙花大量落叶,淹水胁迫下5种花灌木的叶绿素含量显著下降(P<0.05)、可溶性蛋白含量下降、丙二醛含量上升,斑叶鹅掌藤和狗牙花的SOD活性显著下降(P<0.05);旱涝交替胁迫下黄蝉和钟花蒲桃的叶片形态分别表现为Ⅰ级和Ⅱ级,5种花灌木的叶绿素含量均下降,除狗牙花SOD活性上升外,其他4种植物均下降。【结论】综合隶属函数和植物形态分析,5种花灌木耐旱性从强到弱依次为斑叶鹅掌藤、狗牙花、黄蝉、栀子、钟花蒲桃;耐涝性从强到弱依次为栀子、钟花蒲桃、黄蝉、斑叶鹅掌藤、狗牙花;对旱涝交替胁迫的适应性从强到弱依次为黄蝉、钟花蒲桃、斑叶鹅掌藤、狗牙花、栀子。黄蝉可配置于雨水花园和滨水河岸带等环境,斑叶鹅掌藤和狗牙花是建设屋顶花园、节水型绿地的优良植物材料,栀子和钟花蒲桃可配置于滨水绿地、淡水湿地或土壤较为湿润的环境。

[Purpose]The physiological and morphological changes of five tropical flowering shrubs under different water stress treatments were studied to reveal the response of plants to drought and waterlogging stress.[Method]Allemanda schottii,Gardenia jasminoides,Schefflera arboric-ola‘Variegata’,Syzygium campanulatum and Tabernaemontana divaricate were used as experimental materials to conduct four water stress treatments,including normal water supply(CK),continuous drought(CD),continuous flooding(CF),drought and flooding alternation(FD).The morphological changes and the physiological indexes of plants under different water stress treatments were respectively observed and measured.And the stress resistance of plants was comprehensively evaluated by fuzzy membership function method.[Result]Under drought stress,the leaf damage of S.campanulatum suffered the most,which performed grade VI.The SOD activity of five flowering shrubs decreased,malondialdehyde content increased,and chlorophyll content of S.arboricola‘Variegata’decreased significantly(P<0.05).Flooding stress has a significant impact on the external morphology of plants.G.jasminoides growed new roots,A.schottii formed hypertrophic lenticels and growed a lot of new roots and leaves,a large number of leaves of S.arboricola‘Variegata’withered and its root rotted seriously,lots of leaves of T.divaricata fell.Under waterlogging stress,the chlorophyll content of five flowering shrubs decreased significantly(P<0.05),soluble protein content also decreased,however the malondialdehyde content increased,the SOD activity of S.arboricola‘Variegata’and T.divaricate decreased significantly(P<0.05).Under alternate stress of drought and flooding,the leaf morphologies of A.schottii and S.campanulatum were performed as grade I and II respectively,the chlorophyll content of five flowering shrubs decreased,and the SOD activity of T.divaricate increased,while the other four plants decreased.[Conclusion]Combining subordinate function and plant morphology,the tolerance of five flowering shrubs to drought from strong to weak was S.arboricola‘Variegata’,T.divaricate,A.schottii,G.jasminoides,S.campanulatum,the tolerance of five flowering shrubs to waterlogging from strong to weak was G.jasminoides,S.campanulatum,A.schottii,S.arboricola‘Variegata’,T.divaricate,and the adaptability to alternate stress of drought and flooding from strong to weak was A.schottii,S.campanulatum,S.arboricola‘Variegata’,T.divaricate,G.jasminoides.A.schottii can be arranged in rain garden and waterfront riverbank zone,S.arboricola‘Variegata’and T.divaricate are excellent plant materials for building roof garden and water-saving green space,G.jasminoides and S.campanulatum can be arranged in waterfront green space,freshwater wetland or humid soil environment.