The effects of three plant growth regulators,indole-3-acetic acid (IAA),2,4-dichlorophenoxyacetic acid(2,4-D) and kinetin(KT),with concentrations of 0.0,0.5,1.0,2.0,4.0,6.0 and 10.0 mg · L-1 acting as the treatments in a single factorial comparative experiment,on the growth and photosynthetic pigment contents of free-living filaments in Pyropia haitanensis was studied.The results showed that compared to the control group low concentrations of IAA (0.5 ～ 4.0 mg · L-1) and KT (0.5 ～ 2.0 mg ·L-1) had apparent influences on the specific growth rate of filaments,and the most obvious effects were observed in 2.0 mg · L-1IAA and 1.0 mg · L-1KT group,whose algal biomass were 0.90 and 0.52 time higher than those of the control group after 25 d culture,respectively (P ＜ 0.05).However,the high concentrations of IAA and KT (6.0 ～10.0 mg · L-1) significantly inhibited the growth of filaments (P ＜0.05).After 25 d culture,compared to the control group,both 2.0 mg · L-1 IAA and 1.0 mg · L-1 KT significantly stimulated synthesis of Chlorophyll α (Chl a) and Carotenoids (Car),and the contents of Chl a increased by 23.7％ and 23.8％,respectively.While the contents of Car increased by 31.0％ and 28.6％,respectively (P ＜0.05).Whereas,high concentrations of IAA and KT (6.0 ～ 10.0 mg · L-1) significantly reduced the contents of Chl a,presenting as the treated concentration higher,the Chl a synthesis less.In additional,low concentrations of IAA (1.0 ～ 2.0 mg · L-1) treatmeat significantly increased the contents of Phycoerythrin (PE) and Phycocyanin (PC),which were highest in 2.0 mg · L-1 IAA group,and increased by 59.1％ and 45.7％,respectively (P ＜ 0.05).Meanwhile,low concentrations of KT (0.5 ～2.0 mg ·L-1) resulted in massive synthesis of the PE and PC,which were the highest in 0.5 mg · L-1 KT group,and increased by 48.4％ and 50.5％,respectively (P ＜0.05).While high concentrations of IAA and KT (6.0 ～10.0 mg · L-1) significantly reduced the contents of PE and PC (P ＜0.05).But 2,4-D treatments had no apparent influence on the growth and synthesis of photosynthetic pigments.%采用单因素分析法,比较研究了添加3种外源植物生长调节剂(吲哚乙酸IAA、2,4-二氯苯氧乙酸2,4-D、激动素KT)对野生型坛紫菜(Pyropia haitanensis)自由丝状体生长及光合色素含量的影响.结果表明:与对照组相比,低浓度的IAA(0.5～4.0 mg·L-1)和KT(0.5 ～2.0mg.L-1)对藻体的特定生长率有显著影响,以2.0 mg· L-IAA和1.0 mg·L-1KT对藻体的促生长效应最大,培养25 d时藻体鲜重增加最大,分别是对照组的1.90倍和1.52倍(P＜0.05).高浓度的IAA(6.0～ 10.0 mg·L-1)和KT(4.0 ～ 10.0 mg·L-1)却会抑制藻体生长(P＜0.05).培养25 d时,与对照组相比,2.0 mg·L-1IAA和1.0 mg·L-1KT均有利于叶绿素a(Chla)和类胡萝卜素(Car)的合成,Chl a含量分别增加了23.7％和23.8％;Car含量分别增加了31.0％和28.6％ (P ＜0.05).然而,高浓度的IAA和KT(6.0、10.0 mg·L-1)不利于Chla的合成,其处理浓度越高,Chla含量下降越多.与对照组相比,较低浓度的IAA(1.0～2.0 mg·L-1)明显促进藻红蛋白(PE)和藻蓝蛋白(PC)合成,其中2.0 mg·L-1IAA处理组PE、PC含量最高,分别增加了59.1％和45.7％ (P ＜0.05).较低浓度的KT(0.5 ～2.0 mg·L-1)均有利于PE、PC合成,其中0.5 mg·L-1KT处理组的PE、PC含量增加最多,分别提高了48.4％和50.5％(P＜0.05).高浓度的IAA(6.0、10.0 mg·L-1)和KT(10.0 mg·L-1)则明显降低了PE、PC合成(P＜0.05).2,4-D对藻体的特定生长率和光合色素合成无显著影响(P＞0.05).
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