补光时间和光质对温室甜椒叶片生长、碳代谢的影响

Effects of Supplemental Light Quality and Duration on the Growth and Carbon Metabolism of Leaves of Greenhouse-grown Sweet Pepper

为探究发光二极管(LED)补光对温室甜椒叶片生长及碳代谢的影响,以甜椒品种‘奥黛丽’为试材,设置红光(R)和蓝光(B)组合2:1(2R1B)、4:1(4R1B)、8:1(8R1B)3种光质,2 h(18:00—20:00)、4 h(18:00—22:00)和8 h(18:00—次日02:00)3个补光时间,以不补光为对照(CK),研究补光时间及光质对甜椒叶片生长、元素含量、糖含量及碳代谢关键酶活性的影响。结果表明,光质与补光时间能显著影响甜椒叶片的生长及碳代谢,且两者之间存在交互作用。与CK相比,光质2R1B处理的比叶重、钾、果糖、淀粉含量显著降低;而光质4R1B和8R1B处理的叶片数、总叶面积、叶绿素总量、生物量净积累速率(NAR)、总糖含量及酸性转化酶(AI)、中性转化酶(NI)和蔗糖合成酶(SS)活性显著高于CK,且8R1B处理略优于4R1B处理,说明红光比例增大有利于叶片生长和碳代谢;光质对甜椒叶片氮、磷、钾、镁元素的含量影响不显著。除光质2R1B处理外,在同一光质下,随着补光时间的延长,甜椒的叶片数、比叶重、叶面积指数(LAI)、NAR、总糖、果糖、淀粉含量及AI、NI、SS和蔗糖磷酸合成酶(SPS)活性逐渐升高,且补光8 h处理显著高于补光2 h。综上,增大红光比例的同时延长补光时间有利于甜椒叶片生长、提高碳代谢水平和糖含量、增加干物质积累,光质8R1B补光8 h的处理表现最好。

To explore the effect of LED(light emitting diode)supplemental light on the growth and carbon metabolism of leaves of greenhouse-grown sweet pepper(Capsium annuum),‘Aodaili’was chosen as the material to investigate the effects of different light qualities and duration on the growth,mineral elements’content,sugar content and activities of key carbon metabolic enzymes.The LED as light source was provided with three light qualities,including the ratio of red(R)and blue(B)light of 2:1(2R1B),4:1(4R1B)and 8:1(8R1B),and three supplemental light duration,including 2 h(18:00-20:00),4 h(18:00-22:00)and 8 h(18:00-02:00 next day),and no supplemental light was taken as the control(CK).The results showed that the growth and carbon metabolism of leaves of sweet pepper were significantly affected by light quality and light duration,which had an interaction between them.Compared with those of CK,the specific leaf weight(SLW),the contents of potassium,fructose and starch significantly decreased under 2R1B treatment;while the leaf number,total leaf area,total chlorophyll content,biomass net assimilation rate(NAR),total sugar content,and the activities of acid invertase(AI),neutral invertase(NI)and sucrose synthase(SS)were significantly higher than those of CK under 4R1B or 8R1B.Moreover,the 8R1B treatment was slightly better than 4R1B treatment,indicating that increasing the proportion of red light was beneficial to leaf growth and carbon metabolism.Light quality had no significant effect on the contents of nitrogen,phosphorus,potassium and magnesium in leaves of sweet pepper.Under the same light quality,the leaf number,SLW,leaf area index(LAI),NAR,total sugar content,fructose content,starch content and the activities of AI,NI,SS and sucrose phosphate synthase(SPS)of sweet pepper increased gradually with the duration of supplemental light except the 2R1B treatment.Moreover,these indexes were significantly higher under light treatment of 8 h than those under 2 h.In conclusion,increasing the proportion of red light and the duration of supplemental light is beneficial to the leaf growth,and can improve carbon metabolism and sugar content,and increase dry matter accumulation.The treatment of 8 h under 8R1B is optimal for sweet pepper.