Abstract: Under laboratory artificial climate incubator and in glass greenhouse, two experiments of simulated cotyledon predation were conducted to test the effects of different cotyledon excision (excision of 1/4, 1/2 and 3/4 cotyledon, with non excision cotyledon as control) on seed germination and early seedling growth of Quercus wutaishanica, a dominant tree species in warm temperate deciduous forest. The germination percentages (GPs) of seeds planted in the artificial climate incubator were higher than that of the control after the cotyledon being partially excised and a significant difference was detected between the control and 1/4 cotyledon excision treatments. Cotyledon excision accelerated the timing of seed germination, or in other words, cotyledon removal increased the coefficient of  germination rate  (CGR), but no significant difference in CGR was observed among the control and cotyledon excision treatments. Among all cotyledon excision treatments, the 1/4 cotyledon excision treatment significantly increased the germination index (GI) of seeds. It was found that cotyledon excision did not significantly affect vigor index (Ⅵ). When seeds were planted in the pot in the glass greenhouse, cotyledon excision did not significantly increase GP but did result in the acceleration of germination course and the increase of GI. Slight increase of VI was observed with 1/4 cotyledon excision, but a large decline in Ⅵ was observed with 1/2 or 3/4 cotyledon excision. Cotyledon excision resulted, in varied degrees, in the decreases of shoot height, basal stem diameter, taproot length, number of lateral root, maximum of lateral root, leaf number, leaf area per seedling and total dry mass of Q. wutaishanica seedlings. There were significant differences in seedling shoot height among cotyledon excised and nonexcised treatments. Other parameters of seedlings with 1/2 and 3/4 cotyledon excision were significantly lower than that of seedlings without cotyledon excision. Cotyledon excision had little impact on root shoot ratio of seedlings. Increase in specific leaf area (SLA), specific shoot length (SSL) and specific root length (SRL) of seedlings were detected due to cotyledon excision. Compared to the control treatment, 1/2 cotyledon excision significantly increased SLA of seedlings, and all cotyledon excision treatments significantly increased SSL of seedlings. Also, 1/2 or 3/4 cotyledon excision significantly increased SRL of seedlings compared with no or 1/4 cotyledon excision.

Key words: Pyruvate Kinase, G6PDH, walnut, fat, ACCase