Effect of Different NH+4-N/NO-3-N Ratios on the Photosynthetic and Fluorescence Characteristics of Sesame Seedlings
XU Zixian
LI Yinshui
HAN Peipei
LIAO Xiangsheng
HU Xiaojia
XIE Lihua
YU Changbing
ZHANG Xiurong
LIAO Xing
QIN Lu
Abstract：In order to explore the effect of different NH+4-N/NO-3-N ratios on the photosynthetic characteristics of sesame seedlings and the suitable ratio for the growth of sesame,hydroponic experiments were performed to study the different NH+4-N/NO-3-N ratios(10:0,9:1,3:1,1:1,1:3,1:9,0:10) on the photosynthetic characteristics,pigments and chlorophyll fluorescence of sesame cultivars ZZ13 and L12.Results showed that high NH+4-N/NO-3-N ratio significantly inhibited the growth of sesame,resulting in the death(10:0 and 9:1) and the reduced dry weight(3:1) of sesame seedlings.With the decrease of NH+4-N,the inhibition were alleviated,moreover,the shoot dry weight of ZZ13 and L12 reached maximum under NH+4-N/NO-3-N ratio at 1:9.While the the content of Chl a,Chl b,Chl (a+b) achieved the highest values under NH+4-N/NO-3-N ratio at 1:9 and 0:10,respectively.However,these parameters greatly decreased when applied the NH+4-N/NO-3-N ratio at 3:1.The photosynthetic rate(Pn) and respiratory rates(Tr) of two cultivars were also greatest under NH+4-N/NO-3-N ratio at 1:9,reversely,the Pn and Tr of two cultivars were both greatly reduced when applied more NH+4-N(3:1 and 1:1),these two parameters were sensitive to addition of NH+4-N.Furthermore,compared to the total NO-3-N treatment,appropriately applied with NH+4-N 1:9 significantly improved the PSⅡactivity of ZZ13,as indicated by the significant increase of Fv/Fm,ΦPSⅡand decrease of qN.However,the NH+4-N/NO-3-N ratio at 3:1 both suppressed the PSⅡactivity of two cultivars,these parameters exhibited reversed tendency as compared with ratio at 1:9.These results indicated that the NH+4-N/NO-3-N ratio at 1:9 was more suitable for the growth of sesame seedlings in the present study,especially for ZZ13,the improvement of the PSⅡactivity might promote the photosyntheis of sesame.While the higher proportion of NH+4-N had an undesirable influence on the photosynthetic pigment content and its composition,PSⅡactivity,Pn and Tr,then finally seriously inhibited the photosynthesis and growth of sesame seedlings.
Keywords：sesameNH+4-N/NO-3-N ratiophotosynthetic characteristicsphotosynthetic pigmentschlorophyll fluorescence
Publication Date：2017-09-01
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：8( 37-44 )