Stimulation of phytohormones on senescence of cut chrysanthemum
Weiming Guo , Wuqing Zheng, Li Zheng and Zhihong Zhang
Dept. of Ornamental Horticulture, Nanjing Agricultural Univ., Nanjing, Jiangsu, P.R. China, 210095
2002
บทคัดย่อ
The paper is to clarify the relations between phytohormones and senescence of cut chrysanthemum, eespecially essrly wilting of the leaves. The results by GC showed that cut crysanthemum produced little ethylene during senescence, but both ACC(1-aminocyclopropane-1-carboxylic acid) and ethephon with high concentration, especially ethephon, could induce ethylene evolution in leaves and florets, make a leaf etiolation, and shorten a vaselife. The results showed indirectly that cut chrysanthemum must be belong to non-ethylene climatic type failing to produce ACC and ethylene caused by ACS and ACO deficiency, and that it also belongs to non-ethylene-sensitive type. The results by ELISA showed that the iPA [6-(2-isopentenyl) adenosine] contents decreased continuously, the ABA and lAA contents increased continuously in leaves and florets of cut chrysanthemum durign vaselife. But it was noticed that GA1+3 were not deficient in the later vase period and appeared a raising trend, GA1+3 could only increase diameter of the corolla. The decrasing trend of iPA contents during senescence was delayed and the vaselife was prolonged by 6-BA pulse treatment. By ABA pulse treatment, a sharp increase of ethylene in leave and florets was induced, especiallly in leave, and leaf etiolation and early wilting were also accelerared. Ethylene evolution induced by lAA was lower than that by ABA. It was observed that by 6-BA pulse treatment after by ABA, the ethylene evolution in leaves induced by ABA was inhibitd greatly. All results showed tha the cytokinin, represented by iPA, is the important factor delaying the senescence of the cut chrysanthemum, especially delaying early wilting of the leaves, and that ABA must be the main factor accelerating the senescence, for ABA (and lAA) could induce the ethlene evolution of the leaves, and accelerate etiolation and early wilting of the leaves, especially which under dry storage at 2 0C.