| Water is very important for plant physiology process. There are two main plant water use processes which one is the direct evaporation and the other is transpiration from porosity or lenticel, which is accounted for more than 99.8 percent. Transpiration is a complicated physical and biological process, which is very important for better understanding the plant life activity process and its relationship with environment ecological.Gymnosperms and angiosperms (including single cotyledons plants and dicotyledonous plants) are the main components of higher plants, which are evolved in different geological periods, respectively. Each one has their unique moisture ecological characteristics. Ginkgo biloba L.(gymnosperms), Myrica rubra Sieb.et Zucc (dicotyledonous plants) and Phyllostachy edulis (Carr) Lehaie (monocotyledons) are choosed in this article, to measuring sapflow in three tree species by using thermal dissipation probe technology (TDP), and portable infrared gas analyzer open system, combining with water, photosynthetic characteristics and environmental factor synchronous variation features:1. Distinguishing ginkgo water use seasonal variation and the differences between male and female, and to discuss the reason for further study on the evolution of ginkgo water physiology, provides the basis for the urban greening irrigation practice.2. Analysising Myrica rubra Sieb.et Zucc water use seasonal variation, and the differences between male and female, providing a reasonable irrigation technology for agricultural and afforestation.3. To study the sapflow among bamboo, rhizome and shoot during the explosively growth period in three years by setting the basic unit of"one bamboo-one rhizome-one shoot". For better management of bamboo forest which is invading the local original ecological system, and propose scientific basis for water source protection.Results show that: (1) Daily sapflow variation of ginkgo in three seasons are all the single-peak curve, the peak value in spring is the highest, then summer, autumn. The peak value of female is higher than male. The Pn, Gs, Tr of both male and female strains rises along with light intensity increases, the maximum value of three parameters of female are greater. And the WUE of male strains is more sensitive to high PAR.(2) Daily sapflow variation of Myrica rubra Sieb.et Zucc in three seasons are all the single-peak curve, The peak value and the daily mean value in summer are both the highest, then is spring, autumn. The peak value of male is higher than female, but the daily mean value is not. There is a photo inhibition phenomenon in the Pn, Gs of male strains and Pn, Gs, Tr of female strains, and the WUE of male and female strains are similar. The maximum value of the four parameters of male strains are greater than which of female strains. It is estimated that should increase irrigation for male in practice.(3) From March to June, the sapflow in the unit of"one bamboo-one rhizome-one shoot"is along with the shoot - bamboo high growth, start from low value to high. There is no significant different of daily mean value between The Big Year and The Small Year. And the daily mean value is positively correlated with temperature while is negatively correlated with relative humidity. The moisture content of shoot is higher than stem and rhizome.The photosynthetic rate, transpiration rate, stomatal conductance of bamboo in spring has a mild photo inhibition, while is not in summer. Water use efficiency in summer is suffered from more serious photo inhibition than in spring. |
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