Effects Of Light Quality And Plant Growth Regulator On Ornamental And Relative Characteristics Of Rhododendron Simsii

Taking Rhododendron simsii’Pinghua’as the object of study, this paper studied the effects that different light quality(white, red, blue) and different concentrations of daminozide (B9)(0,300,600,900mg/L) or gibberellin(GA3)(0,500,1000,1500mg/L) on its ornamental value, physiological and photosynthetic characteristics. This study provieds a scientific basis and technical support for the commercial production of R. simsii. The main results are as follows:(1) Comparing with control, the flowering duration was prolonged, the flower diameter was increased, the flowering rate and the content of anthocyanin in petals were enhanced by all the other treatments. Using the mixture of blue light or red light and B9or GA3in some certain concentration was more effective than using any alone in improving omanmental values. The treatments of red light+600mg/LB9and red light＋1000mg/LGA3increased the flowering duration and flowering rate conspicuously. The treatments of blue light+300mg/LB9, blue light+600mg/LB9and blue light＋15OOmg/LGA3were the most conductive to increase the flower diameter and the content of anthocyanin in petals.(2)The treatments of B9, GA3, red and blue light induced the increases of chlorophyll a and chlorophyll b. But the treatments of blue light+300mg/L B9and blue light+1500mg/LGA3made the chlorophyll a increase more, while the treatments of red light+600mg/L B9and red light＋15OOmg/LGA3induced increasing of chlorophyll b more. Comparing with control, the other treatments promoted the net photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Cond) and intercellular CO2concentration(Ci) of R. simsii’Pinghua’, enhanced the photosynthetic capability and also promoted the photosynthetic pigment to absorb and transform the light energy more coordinating. Cond was the main facters of Pn.(3)Under dissimilar light and plant growth regulators, the physiological activities of R. Simsii were improved. Besides these treatments were alsa good for the accumulation of soluble sugar and anthocyanin and for the decreases of the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA). The treatments of red light+600mg/LB9, blue light+300mg/LB9, red light＋1000mg/LGA3, red light+1500mg/LGA3 and blue light+1500mg/LGA3had the best treatments effects which provided powerful guarantee for normal growth of flowers and leaves.(4) In order to promote the development of flower bud, B9inhibited vegetative growth to reduce it’s competeing nutrient substance. But the synthesis and support of nutrients were relative lack during the later period, and showed antagonise effect when B9was in too high concentration. GA3adjusted flowering through promoting vegetative growth and inducing the synthesis of relative substance. Dissimilar GA3and red or blue light keeped synergy effect to promote each other and the effects continued until later flowering stage, so that their flowering duration was ralative longer.Synthesized all the physiological indices, the treatments of red light+600mg/L B9, red light+1500mg/LGA3, blue light+300mg/LB9and blue light+1500mg/L GA3were better, and the treatment of red light＋1000mg/LGA3was the best treatments, so as to delay the aging of flowers and leaves. They provided the good basis of material for florescence and improving the quality of flowers.