施肥对闽楠幼树PSⅡ叶绿素荧光快速光响应曲线的影响

Rapid light curves of PS Ⅱ chlorophyll fluorescence parameters in leaves of Phoebe bournei saplings fertilized

以4年生闽楠幼树作为试验材料,研究不同施肥处理对幼树叶绿素荧光参数的影响及其快速光响应曲线差异。结果表明,初始荧光F_o和最大荧光F_m在施肥一季度后即冬季出现先降低后升高趋势,在施肥三季度后即夏季出现先升高后降低的趋势;PSⅡ最大光化学效率(F_v/F_m)和PSⅡ潜在光化学效率(F_v/F_o)均是中度施肥处理优势显著。不同施肥处理下叶绿素荧光参数结果表明,PSⅡ的实际光量子产量Yield、荧光光化学淬灭系数qp随光强的增加呈现下降趋势,而相同光照强度下,冬季随施肥量的增加其Yield值越大,夏季则是中度施肥量样地Yield值较突出;相对电子传递速率ETR、非光化学淬灭系数q N、NPQ随光强增加呈上升趋势,相同光照强度下ETR冬季数据大量施肥处理样地显著高于其他,夏季未施肥样地明显低于施肥样地,非光化学淬灭系数q N、NPQ高温季节在同光照条件下未施肥处理样地明显高于施肥样地。说明施肥会影响闽楠幼树PSⅡ反应中心开放程度和活性,中度施肥对各项荧光参数促进作用明显,而大量施肥在高温季节则会导致PSⅡ反应中心部分关闭产生光抑制现象。

A four-year-old Phoebe bournei saplings as test material,study effects of different fertilization on chlorophyll fluorescence parameters and rapid light curve for saplings.The results showed that the initial fluorescence Fo and the largest Fm present trend of first decreases and then increases after fertilized of a quarter,and the two parameters first increases and then decreases after fertilized of nine months.maximal PSⅡquantum yield（Fv/Fm）and latent PSⅡquantum yield（Fv/Fo）showed the similar trend that maximum present to moderate fertilized.The rapid light curves of chlorophyll fluorescence parameters were also measured at various light intensities.The effective PSⅡquantum Yield and coefficient of photochemical quenching（qp）decreased with the increase of light intensity.Yield increased with the increase of fertilizing amount in winter,Yield with medium fertilizing amount was more significant in summer.Electron transport rate（ETR）,coefficient of nonphotochemical quenching（q N）andnon-photochemical quenching coefficient（NPQ）increased with the increase of illumination intensity.ETR of sample with plenty fertilizer overtop others in winter and sample of contrastive plots lower than other samples that been fertilized in summer.q N and NPQ of contrastive plots markedly overtop others with fertilizer in hot season.Results show that fertilizer could affect the openness andactivity of PSⅡreaction center which Phoebe bournei saplings.Moderate fertilizer could promote fluorescence parameters of samples,heavy fertilization made part of PSⅡreaction center closure and then led photo inhibition in hot season.