Research On Drought Resistance On Anatomical Structure Of Leaves And Cold Resistance Of New Black Poplar Clones

It is an important field in genetic breeding to carry out stress resistance breeding ofpoplar. In winter, it is so cold and dry in the north part of our country that many plants can notgo through winter, especially in the northwest area. Cultivating new poplar varieties withstrong cold and drought tolerance ability is an effective means of providing materials forcultivation and getting great poplar productivity. Also the cultivation of new poplar varietiesis of great significance for the construction of the ecological environment in northern China.In this research, three new poplar clones were studied to compare their cold resistance anddrought resistance. Three new poplar clones were03-south4-1,03-north1-15and03-south1-13, their mother (I-69, P.deltoides cl.‘Lux’), Populus deltoides cl.Nankang(P.deltoides cl.‘Lux’×P.deltoides cl.‘Harvard’) and Shaanxi No.3(P.deltoides cl.‘Lux’×P.deltoides) were studied too. Main conclusions were made as follows:1. The thickness of leaf blade, the thickness of principal vain, the thickness of lowerpalisade, the thickness of leaf cuticle, the thickness of upper epidermis and the thickness oflower epidermis is respectively arranged from332.4to404.61μm,2850.61to3453.71μm,107.01to128.92μm,2.49to3.83μm,19.50to23.37μm and16.53to19.37μm. The resultsshowed03-south4-1had significant disparity compared with03-south1-13in the aboveindexes. The thickness of upper palisade and the palisade/spongy is respectively arrangedfrom107.48to128.92μm and0.73to0.78. The results showed03-north1-15had significantdisparity compared with03-south4-1and03-south1-13in the two indexes.2. The results showed the drought resistant capability decreased in the order of03-south4-1,03-north1-15, Populus deltoides cl.Nankang, I-69,03-south1-13, Shaanxi No.3.As the anatomical structure indexes used in a comprehensive evaluation,03-south4-1and03-north1-15were better in adapting to arid environments than03-south1-13.3. The correlation degrees of the eight anatomical structure indexes and drought resistantwere bigger than0.5and were decreased in an order from big to small as: the thickness of leafcuticle> the thickness of lower palisade tissue> the thickness of upper palisade tissue> thethickness of leaf blade> the thickness of upper epidermis> the thickness of lower epidermis> the thickness of palisade tissue/the thickness of mesophyll tissue> the thickness of principal vain.4. Relative conductivity was negatively correlated with cold resistance. It risesdifferently under different low temperature processing, the value and the rate of change in03-south4-1and Shaanxi No.3were conspicuous and it is not so obvious in Populus deltoidescl.Nankang, I-69and03-north1-15.5. The content of Malondialdehyde was also negatively correlated with cold resistance.The two new clones03-south4-1and03-north1-15had significant disparity compared withShaanxi No.3, Populus deltoides cl.Nankang and I-69in content of Malondialdehyde afterthey were processed under low temperature.6. Water saturation deficit was negatively correlated with cold resistance. Watersaturation deficit value of Shaanxi No.3and03-south4-1were less than Populus deltoidescl.Nankang and had significant disparity compared with Populus deltoides cl.Nankang, while03-south4-1,03-north1-15and I-69had no significant disparity.7. The capability of recover experiment can be more intuitively reflect the damagedegree of seedling under low temperature. With the decrease of the processing temperature,the germination rate of each clone showed different degree of decrease and03-north1-15andPopulus deltoides cl.Nankang had lower decrease degree of germination rate.8. By the measurement of water saturation deficit, relative conductivity, content ofMalondialdehyde and the germination rate,03-north1-15was better in adapting to coldenvironments than03-south4-1.