Evaluation Of Dendrobium Plants Introduction And Study Of Spermidine On The Flowering Regulation Of Nobile-type Dendrobium

Dendrobium, a genus of the Orchidaceae family, is perennial herbs. With great ornamental and medicinal value, Dendrobium resources have been excessively excavated and developed, so we should do the introduction and protection work right. At the same time, flowering regulation is especially important to the market prospect of the nobile-type Dendrobium which becomes a newly-arised lunar New Year flower. In the experiment, firstly,18 species wild Dendrobium and 4 nobile-types Dendrobium have been used to do introduction observation and comprehensive ornamental evaluation. At the same time, the effects of different concentrations of Spermidine on the growth and physiological indicators of the 4 nobile-types Dendrobium have been studied.The major results are summarized as follows:l.The introduction observation, evaluation and screening of Dendrobium plants.Gray correlation analysis method has been used to comprehensively evaluate the adaptability and ornamental effects of the 18 species wild Dendrobium and 4 nobile-types Dendrobium. The observation results showed that:All these Dendrobium materials were under normal vegetative growth. The correlation degree of nobile-type Dendrobium ’V3’, nobile-type Dendrobium ’V1’ and other 3 species wild Dendrobium:Dendrobium thyrsiflorum, Dendrobium chrysanthum and Dendrobium chrysotoxum with the ideal species which obtained by gray correlation analysis were over 0.7, so they were regarded as having relatively good adaptability and can be directly used for greenhouse cultivation; The correlation degree of nobile-type Dendrobium ’V2’, nobile-type Dendrobium’V4’ and other 9 species wild Dendrobium:Dendrobium nobile, Dendrobium moschatum, Dendrobium henryi, Dendrobium crepidatum, Dendrobium devonianum, Dendrobium trigonopus, Dendrobium officinale, Dendrobium crystallinum and Dendrobium longicornu with the ideal species were over 0.6. These species also have relatively good adaptability and ornamental value, but they should have further experimental observation. The correlation degree of other 6 species Dendrobium:Dendrobium christyanum, Dendrobium gibsonii, Dendrobium fimbriatum, Dendrobium cariniferum, Dendrobium loddigesii and Dendrobium moniliforme with the ideal species were below 0.6, that is say they have relatively poor adaptability. So the conditions of existing greenhouse cultivation management should have further improvement to develop their ornamental value.2.The effects of different concentrations of exogenous Spermidine with different spraying time on the flowering of nobile-type Dendrobium.The principal component analysis has been used to comprehensively evaluate the effects on the flowering of 2 nobile-types Dendrobium. The results showed that among all the treatments of different Spd concentrations sprayed on October 15th, November 15th and December 2nd in 2011, the best treatment for nobile-type Dendrobium ’V1’ was 0.01 mmol/L Spd with the spraying time on December 2nd. It’s flowering rate was higher than other treatments and increased 11.1% compared to the control. Meanwhile, the first flowering time was advanced by 2 days and prolonged 2 days. However, for nobile-type Dendrobium’V4’, the treatment of 0.01 mmol/L Spd with the spraying time on November 15th had the best effect than other treatments. It’s flowering rate was the highest among the treatments and increased 33.4% and the florescence was remarkably extended 17 days. In general, the number of flowers and flowering nodes were a little increasing but not significant than other Combinations.3.The effects of exogenous Spermidine on the Physiological and biochemical characteristics of nobile-type Dendrobium.Comparing the best treatments and controls of nobile-type Dendrobium ’V1’ and ’V4’, the results showed that the contents of soluble sugar in the leaves of nobile-type Dendrobium stayed at a relatively low level in initial differentiation phase and then continued to rise. The contents of soluble sugar of best treatment was higher than the control. The contents of total nitrogen in the leaves of both best treatment and the control reached a relatively high level slowly from a low level, then the contents of total nitrogen of the best treatment was higher than the control in the later period; The C/N decreased with a narrow range in the early period and then increased which showed that relatively high C/N is conducive to flower bud differentiation. The contents of POD in the leaves of the best treatment decreased gradually in initial differentiation phase and then increased, the control had the nearly opposite trend. The contents of Putrescine, Spermidine, Spermine in the leaves of ’V1’ under the best treatment reached a peak with 14 days later than the control. Meanwhile, their maximum were bigger than the control’s. The contents of Putrescine, Spermidine in the leaves of’VI’reached a maximum and then dropped down suddenly. The contents of Spermine haven’t been detected.4.The effects of exogenous Spermidine with different cultivation mediums on the flowering of nobile-type Dendrobium.After different Spd concentrations were sprayed on sphagna, Coconut block and their mixture (sphagna:coconut block=1:1), the principal component analysis has been used to comprehensively evaluate the morphological parameters of florescence. The results showed that there were obvious differences (p<0.05) among the treatments of both the nobile-type Dendrobium’V2’and’V3’on first flowering time, florescence, flower number and flower diameter. The best treatment for the nobile-type Dendrobium ’V2’ was 0.1 mmol/L Spd with spraying on the sphagna, and 0.1 mmol/L Spd with spraying on the coconut block was the best treatment for nobile-type Dendrobium ’V3’. The best Spd concentration of the two nobile-types Dendrobium were 0.1 mmol/L.