Photosynthetic Efficiency And Productivity Classification Of Rosa Roxbunghii Under Different Soil Water Conditions

Drought has become arid and semi-arid areas of vegetation restoration and agroforestry development of the main factors.Loess hilly-gully region, this paper mainly drought to cili(Rosa roxburghii Tratt.) as experiment material, in shanxi zhongyang vehicle sound valley forest Settings potted simulation experiment, through the provision of various soil moisture gradient, the determination of the optical response of the gas exchange parameters and chlorophyll fluorescence parameters changing with the soil moisture, clarify thorn pear photosynthetic rate, transpiration rate and water use efficiency and chlorophyll fluorescence parameters in different gas exchange parameters, such as soil moisture under the condition of continuous variation process, revealing the prickly pear gas exchange parameters change, the inner mechanism of determining maintain thorn pear higher photosynthetic rate and water use efficiency of soil moisture range classification is carried out on the soil moisture productivity.To guide the prickly pear provide certain theoretical basis for reasonable water management.Research shows that:(1) the thorn pear under severe water stress, Pn, Tr, WUE, change law of "serious nap" type, photosynthesis in leaves are suppressed by the strong light stress situation.At this time of the moisture become the main factors that influence the Pn.And where appropriate, under the condition of water stress intensity as the main limiting factors.(2) under moderate water stress, the prickly pear leaf chlorophyll absorbed light energy is used for electron transfer of share increase, heat dissipation is also low.As stress deepens, thorn pear start light damage defense mechanism, increase the heat dissipation to avoid the destruction of the photosynthetic mechanism effectively.And under severe water stress, Fo with NPQ growth to the maximum, blade for conversion of light energy after passing severe suppression, PS destroyed, thus speculate that the destruction of the PS is likely to be Ⅱ Ⅱnon stomatal factor to the decline in photosynthetic rate.(3) under the condition of different water through the light intensity thorn pear response analysis of the gas exchange parameters, it is concluded that the suitable soil moisture conditions for the growth of thorn pear and light intensity range.Average value(that is, to maintain higher Pn thorn pear) RWC in the range of 43.6% ~ 87.4%, the range can be used as a guarantee of thorn pear production suitable soil moisture range.Maintain the highest Pn corresponding RWC value of 73.3%, in the case of enough moisture the RWC values can be used as a reference standard soil irrigation to boost production.RWC between 36.5% ~ 36.5%, the WUE can maintain higher values.Maintain the highest WUE RWC at 52.6%, the moisture conditions to ensure a higher photosynthetic productivity in under the premise of efficient water right.As a result, the soil moisture conditions for basis points for water-saving irrigation water-saving agroforestry has certain guiding significance to the production practice.