Study On Drought-resistance Of Five Forages From The Northwest Plateau Of Sichuan Province

This paper chose five kinds of forages which have been promoted and cultivated in the Northwest Plateau of Sichuan Province:Kengyilia rigidula’Aba’, Elymus sibiricus cv.’chuancao NO.2’, Elymus nutans’Aba’, Avena sativa L.cv.’Aba’and Phalaris arundinacea L. cv.’chuancaoyin No.3’as the test materials. This thesis studied on the seeds germination Characteristic under the osmotic stress of polyethylene glycol6000(PEG-6000), to evaluate drought resistance in the germination stage. Using one factor design, pot experiment was carried out to study the dynamic variety of physiological biochemical indexes and the relationships of physiological biochemical indexes between normal water and under drought treatment were discussed in seeding stage. Leaves’ paraffin sectioning was manufactured to observe the drought anatomical structure characteristics in flowering stage. The five forages of drought resistance were compared among in germination stage, seeding stage and flowering stage and a comprehensive evaluation of drought resistance was conducted.1. As the concentration of PEG-6000became more and more high, the germination force, the germination index and the germination drought resistance index of the5species had tended to decline. And Phalaris arundinacea L. cv.’chuancaoyin No.3’did not get germinate and others’germination characteristics achieved the maximum controling when PEG-6000treatment was200g/L.50g/L concentration PEG-6000improved germination characteristics. The growth of embryo and radicle were promoting except Avena sativa L.cv.’Aba’ and phalaris arundinacea L. cv.’chuancao No.3’when concentration PEG-6000was50g/L. Higher concentration PEG-6000, the growth of radicle and germ were restrained, and radicle less than embryo was inhibited. Radicle-plantule ration was increased with PEG-6000of stress concentrations rising. Kengyilia rigidula ’Aba’ was highest rising, and the DRI is3.2646.2. The leaves of the test materials showed the physiological adaptive under drought stress, in the form of:①the leaves of the relative water content under drought stress were less than normal water treatment and the decrease rang of the relative water content(RWC) along with prolonged stress. Kengyilia rigidula’Aba’on the7d and14d drought stress, RWC content was significant higher than other grasses (P<0.01).②The leaves of cell membrane were hurt, relative electric conductivity (REC) and malondialdehyde (MDA) content under drought stress increased. Increasing range and stress time were positively correlated③Protective enzymes (POD, and SOD) activities rose, and the increment had been consistent with stress time process; But the increase range of POD activity of Avena sativa L.cv.’Aba’ and SOD activities of Avena sativa L.cv.’Aba’、Phalaris arundinacea L. cv.’chuancao No.3’、Elymus sibiricus cv.’chuancao NO.2’ and Kengyilia rigidula Aba were decline in21d drought stress.④Photosynthesis was blocked and chlorophyll content declined compared with the CK. The decrease range and the stress time were related.⑤Osmotic regulation substances (Pro, SS) content increased under drought stress, and the rising rate increased as stress time process.3. Kengyilia rigidula ’Aba’ and Elymus nutans ’Aba’ shew obvious xeromorphism features:clear cuticle, stomatal apparatus settlement, epidermal hairs, and developed catheters of vascular bundle.4. The subjection function way of fuzzy mathematics was carried out to appraise the drought resistance of five forages in different growth stages. The results a follow:①Sort of drought resistant at germination stage:Kengyilia rigidula’Aba’>Elymus sibiricus cv.’chuancao NO.2’>Elymus nutans ’Aba’>Avena sativa L.cv.’Aba’>Phalaris arundinacea L. cv.’chuancaoyin No.3’②Sort of drought resistant at seeding stage:kengyilia rigidula’Aba’> Avena sativa L.cv.’Aba’> Elymus sibiricus cv.’chuancao NO.2’>Elymus nutans’Aba’>phalaris arundinacea L. cv.’chuancaoyin No.3’.③Sort of drought resistant at full-bloom stage:Kengyilia rigidula’Aba’’>Elymus nutans’Aba’>Avena sativa L.cv.’Aba’>Elymus sibiricus cv.’chuancao NO.2’> Phalaris arundinacea L. cv.’chuancaoyin No.3’. On the comprehensive evaluation of drought resistance in different growth stages, the result was follows as:Kengyilia rigidula’Aba’> Elymus nutans’Aba’> Avena sativa L.cv.’Aba’> Elymus sibiricus cv.’chuancao NO.2’>Phalaris arundinacea L. cv.’chuancaoyin No.3’.No matter what at the germination period, seedling period or flowering stage, Kengyilia rigidula’Aba’shew stronger drought resistant. So Kengyilia rigidula’Aba’is selected at first as controlling desertification grassland in Northwest Sichuan.