Study On Flowering Rhythm Characteristics Of Ornamental Crabapple

In this study, the flowering phenology, the flowering rhythm and the correlation with temperature were studied systematically with 67 ornamental crabapple cultivars as the research object. The main results were as follows:1) Flowering phenology distributed in late March to early May. In 2013, the initial flowering stage(S1), the full blooming stage(S2) and the end flowering stage(S3)sustained 21 d, 26 d and 24 d. In 2014, the three above sustained 21 d, 26 d and 24 d. According to distribution of S1 in 2013 and 2014, with five days as group interval, 67 ornamental crabapple cultivars were divided into four groups: early group(E), medium group(M), late group(L) and extremely late group(EL). According to the amplitude in two years, the initial blooming time were divided into three groups: stable period(S), micro-vibration period(M) and fluctuation period(F). According to the flowering length of two years, with three days as group interval, 67 ornamental crabapple cultivars were divided into four groups: very short group(VS), short group(S), medium group(M) and long group(L); in 2013 the average flowering length were 11.2 ± 2.4d, while in 2014 the length were 9.9 ± 2.2d.2) Based on the constructed cultivar frequency index(CFI), CFI linear function were fitted respectively of three flowering stage(S1, S2, S3). There is a significant difference in the slope of each of the three flowering stage dynamic function, which were as follows: in 2013: k1(6.4552) <k2(6.9456) <k3(9.1379), in 2014: k4(7.4856) <k5(7.9478) <k6(9.7753), which indicates that flowering phenology rhythm by slow-to-fast paced trends from S1 to S2 and S3. Based on the compare with the k values in the same period of two years, the value in 2014 greater than which in 2013, namely k4> k1, k5> k2, k6> k3, which indicates that flowering phenology process in 2014 faster than which in 2013. Based on distribution of the constructed cultivar diversity index(CDI), the ornamental flowering process was divided into four stages, namely the rising period, high and stable period, falling period and low index period.3) With stable initial flowering cultivar M. ’Pink Spires’ as the object, based on the correlation analysis of initial flowering time and accumulated temperature, according to the correlation coefficient distribution, 250 days before flowering were divided into five stages: positive fluctuation period(D1), wide fluctuation period(D2), negative fluctuation period(D3), high temperature fluctuation period(D4) and stable coefficient period(D5). The significant negatively correlation between flowering time and accumulated temperature(≥6℃) of 57 d ~ 60 d inferred that the effective accumulated temperature required(175.6±9.7)℃. It was found that the coupling coefficient between L and T were different significantly for three cultivar groups distributed in different air temperature zones.According to the mean daily maximum temperature(T) and the average length of flowering stage(L), with 21.4℃ and 22.8℃ as zone boundary, the species were divided into three groups: A, B and C. According to three piecewise coupling functions between L and T which were fitted respectively, area A shown a extremely low degree of coupling, while area B was slightly better and area C was the highest degree of coupling.