光照强度对乐昌含笑幼苗生长及光合特性的影响OA北大核心CSTPCD
Effects of light intensity on growth and photosynthetic characteristics of Michelia chapensis seedlings
为探析乐昌含笑(Michelia chapensis)在不同光照强度下生长及光合能力的适应机制,以乐昌含笑2年生幼苗为试材,经100％(CK)、70％(T1)、50％(T2)、30％(T3)、10％(T4)全光照5个不同遮荫处理1年(3年生),进而对其生长及光合指标进行测定.结果表明,在70％全光照和100％全光照下,乐昌含笑幼苗存活率与株高、地径生长显著高于其他处理.净光合速率在70％光照强度处理时达最高值(8.553 μmol·m-2· s-1);随着遮荫胁迫的加重,净光合速率逐渐下降,在50％全光照下净光合速率下降主要由气孔限制导致,30％全光照和10％全光照下由非气孔限制导致.与其他遮荫处理相比,100％全光照和70％全光照下乐昌含笑叶片具有更高的最大净光合速率(8.166和8.735 μmol·m-2·s-1)、光饱和点(1215.956和1145.328μmol·m-2·s-1)和光补偿点(16.280和13.572 μmol·m-2·s-1).随着遮荫处理水平的提高,PSII反应中心实际光化学效率(ΦPSII)和光化学淬灭系数(qp)逐渐增加,非光化学猝灭系数(NPQ)逐渐下降;吸收光能中光化学反应耗散能量(P)的比例逐渐增大,天线热耗散能量(D)的光能比例逐渐减小;而所有遮荫处理并未对PSII反应中心的最大光化学效率(Fv/Fm)及潜在活性(Fv/F0)产生显著的影响.初步判断,70％全光照最有利于乐昌含笑生长,在中度和重度遮荫条件下乐昌含笑可降低光补偿点、光饱和点、净光合速率和暗呼吸速率,增加PSII反应中心开放程度、电子传递的活性和光能利用率,从而提高其在弱光环境下的生长能力.
To elucidate the adaption mechanism for the growth and photosynthetic capacity of Michelia chapensis un-der different light intensities,two-year-old seedlings were treated with five shading levels of 100％(CK),70％(T1),50％(T2),30％(T3)and 10％(T4)of natural light intensity for one year,after that the growth and pho-tosynthetic characteristics were measured.The results showed that survival rate,plant height and ground diameter were significantly higher under the 70％and 100％light intensity treatments compared with other treatments.The highest value(8.553 μmol·m-2·s-1)of net photosynthetic rate(Pn)was recorded in the 70％light intensity treatment.With increasing shading intensity,Pn values decreased gradually.The decrease of Pn in the 50％natural light intensity treatment was mainly caused by stomatal limitation,but by non-stomatal limitation under the 30％and 10％natural light intensity treatments.Compared to other shading treatments,leaves under the 100％and 70％natural light intensity treatments had higher maximum net photosynthetic rate(8.166 and 8.735 μmol·m-2·s-1),light saturation point(1215.956 and 1145.328 μmol·m-2·s-1),and light compensation point(16.28 and 13.572 μmol·m-2·s-1).In particular,with increasing shading intensity,the actual photochemical quantum yield of PSII(ΦPSII),photochemical quenching coefficient(qp)and proportion of photochemical reaction energy(P)increased gradually,while non-photochemical quenching coefficient(NPQ)decreased gradually.All the treatments did not affect maximum photochemical quantum yield(Fv/Fm)and potential activity(Fv/F0).The results indica-ted that M.chapensis seedlings could reduce light compensation point,light saturation point,net photosynthetic rate and dark respiration rate,while increase the openness of PSII reaction center,electron transfer activity and light use efficiency,thus enhancing growth ability under moderate and serious shading conditions.Our results suggested that 70％of natural light intensity was the most optimal for the growth of M.chapensis seedlings.
周欢;韦如萍;李吉跃;苏艳;胡德活;郑会全
华南农业大学林学与风景园林学院,广州 510642||广东省林业科学研究院/广东省森林培育与保护利用重点实验室,广州 510520广东省林业科学研究院/广东省森林培育与保护利用重点实验室,广州 510520华南农业大学林学与风景园林学院,广州 510642
乐昌含笑光照强度生长光合特性叶绿素荧光
Michelia chapensislight intensitygrowthphotosynthesis characteristicschlorophyll fluorescence
《生态学杂志》 2024 (003)
709-715 / 7
广东省林业科技创新项目(2022KJCX010)资助.
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