Studies On The Photosynthetic Physiological Characteristies And Drought Tolerance Of Heuchera Varieties

In this article, three varieties of Heuchera (Heuchera ‘Paris’、Heuchera ‘Hollywood’、Heuchera‘Strawberry+Swirls’) were used as materials to study its photosynthetic physiological characteristicsand drought tolerance using potted water control methods. The results indicated that:(1) The most wide of light adaptive range was Heuchera ‘Paris’, the narrowest of light adaptivewas Heuchera ‘Strawberry+Swirls’.The high light can be better used by Heuchera ‘Paris’,the low lightlevel can be used by Heuchera ‘Hollywood’. The diurnal variation of net photosynthetic rate of threevarieties of Heuchera displayed double-peaked curves which had obviously photosynthetic noon break.stomatal conductance had similar change trends with Pn, however, the intercellular carbon dioxideconcentration had the opposite change compared with Pn,which showed that photosynthetic noon breakwas caused by non-stomatal factors.The water use efficiency(WUE) of three varieties of Heuchera wasdifferent,WUE can be better used by Heuchera ‘Strawberry+Swirls’,on the other hand,WUE was belimited by Heuchera ‘Hollywood’.(2) Under drought stress, the changes of physiological and biochemical parameters of threevarieties of Heuchera was different. The soil water content、the leaf water potential and the content ofchlorophyll kept decreasing, the relative electric conductivity and the MDA content continued to rise,the changes of the activities of SOD and the soluble protein content were first rises than falls, showedthat the physiological and biochemical activities of Heuchera can be adjusted to adapt to the drought.(3) Changes in chlorophyll fluorescence parameters of three varieties of Heuchera, indicatingdrought stress have some impacts on the chlorophyll fluorescence parameters of Heuchera, the effectivequantum yield and the electron transport rate kept decreasing.The changes of the photochemicalquenching coefficient and The non-photochemical quenching coefficient showed that the photosynthesiscan be adjusted to adapt to the drought.the non-photochemical quenching yield showed that the longtime of drought stress can cause the heavier photosynthetic damage of Heuchera ‘Strawberry+Swirls’.(4) According to the parameter changes, the drought tolerance ability of three varieties ofHeuchera in drought stress condition have been evaluated with subordinate function method. The results are as following: Heuchera ‘Strawberry+Swirls’>Heuchera ‘Paris’>Heuchera ‘Hollywood’.