Effect Of Chlorophyll Content And Chlorophyll Fluorescence Parameters Active Oxygen Metabolism During Inverted Senescing Process Of Wheat Leaves In Different Fertilization Modes

In the present field experiment, normal wheat Shan229, inverted senescing sequenceWenmai19, Zhoumai22and Yumai19was used in the study. From anthesis date to matureperiod, under different fertility levels,some parameters of dynamic variation laws of wheatleaves were determined including chlorophyll content（SPAD）, actual photochemicalefficiency （ΦPSⅡ）, maximum photochemical efficiency （F_v/F_m）, potential activity （F_v/F₀）and heat dissipative quantum ratio（F₀/F_m）, and the superoxide dismutase （SOD）, catalase（CAT）, peroxidase （POD） activities, and malondialdehyde content（MDA）.1. In different fertility conditions, research on chlorophyll content dynamic variationlaws of wheat showed that the SPAD values of wheat top two leaves showed a downwardtrend after anthesis date6days. Comparing with the higher and medium fertility levels, theSPAD values of wheat top two leaves drop faster in the lower conditions. Under higher andmedium fertility conditions, Wen mai, Zhou mai and Yu mai penultimate leaves SPADcontent was significant higher than the flag leaves after anthesis24days; In lower fertilitylevel, SPAD content was significant higher than the flag leaves after anthesis18days; Ascontrasting wheat Shan229, SPAD content of flag leaves was always higher than thepenultimate leaves in different fertility levels.2. In different fertility conditions, research on chlorophyll fluorescence parametersdynamic variation laws of wheat showed that the ΦPS Ⅱ,F_v/F_m and F_v/F₀of wheat top twoleaves showed a downward trend after anthesis date6days, and F₀/F_m showed a upwardtrend. Comparing with the higher and medium fertility levels, the ΦPS Ⅱ,F_v/F_m and F_v/F₀ofwheat top two leaves drop faster in the lower conditions, and F₀/F_m falling faster. Underhigher and medium fertility conditions. The ΦPSⅡ,F_v/F_m and F_v/F₀of Wen mai, Zhou maiand Yu mai penultimate leaves was significant higher than the flag leaves after anthesis24days, F₀/F_m was significant lower than the flag leaves; In lower fertility level, theΦPS Ⅱ,F_v/F_m and F_v/F₀was significant higher than the flag leaves after anthesis18days,F₀/F_m was significant lower than the flag leaves; As contrasting wheat Shan229,ΦPS Ⅱ, F_v/F_m and F_v/F₀of the penultimate leaves was higher than flag leaves in differentfertility levels, but not significant. 3. In different fertility conditions, research on antioxidant enzyme activity dynamicvariation laws of wheat showed that the SOD,POD and CAT activity of wheat top two leavesshowed a declining trend after anthesis date6days, and MDA content showed a rising trend.In the higher and medium fertility levels, the SOD,POD and CAT activity of wheat top twoleaves was higher than in the lower conditions, and MDA content lower than in the lowerconditions. Under higher and medium fertility conditions, the the SOD,POD and CAT activityof Wen mai and Yu mai penultimate leaves was significant higher than the flag leaves afteranthesis24days, MDA was significant lower than the flag leaves; In lower fertility level, thethe SOD,POD and CAT activity was significant higher than the flag leaves after anthesis12days, MDA was significant lower than the flag leaves; As contrasting wheat Shan229,SOD,POD and CAT activity of the penultimate leaves was lower than flag leaves in differentfertility levels.