The chlorophyll fluorescence parameters of cold-resistant cultivar,Dongnongdongmai 1,and CK,Jimai 22,were measured during cold acclimation and frozen periods.The results showed that maximum fluorescence yield(Fm),maximum quantum yield of PS II(Fv/Fm),actual quantum yield(yield),photochemical quenching(qP)in new leaf of CK Jimai 22 was significantly higher than that of Dongnongdongmai 1 in the cold acclimation periods.After the low temperature acclimation,these parameters of Jimai 22 declined rapidly,and were significantly lower than that of Dongnongdongmai 1.The changing trend of Fo during cold acclimation and frozen periods was as Fo in the new leaf of Dongnongdongmai 1 was stable and its reduction in Dongnongdongmai 1 and Jimai 22 were 26.2% and 52.8%,respectively.The fluorescence parameters tendency in old leaf of Dongnongdongmai 1 was consistent with that of Jimai 22,these fluorescence parameters in old leaf of Dongnongdongmai 1 were significantly higher than that of Jimai 22 after cold acclimation period.Chlorophyll fluorescence parameters can be used to identify the cold resistance of wheat cultivars.The identification stage should be at the end of cold acclimation and the beginning of frozen period.The test position of wheat seedling should be the new leaf of cultivar.

为比较抗寒性不同的冬麦品种对低温胁迫的适应性,在低温驯化及封冻阶段对东农冬麦1号(抗寒)、东农705(较抗寒)和济麦22(不抗寒)3个品种的植株形态和叶、叶鞘、分蘖节的若干生理指标进行了调查.结果表明,东农冬麦1号在封冻前形成的分蘖数、分蘖叶数显著高于其他两个品种;低温胁迫下3个品种各个部位的含水量均降低,东农冬麦1号地上部含水量降低较快,分蘖节含水量降低较慢且保持较高水平,而济麦22地上部含水量降低较慢,分蘖节含水量降低较快.电导率变化表明,东农冬麦1号、东农705品系和济麦22叶片分别在封冻后30、20和0 d死亡.东农冬麦1号叶片、叶鞘的可溶性总糖含量最高,济麦22最低;封冻期东农冬麦1号分蘖节可溶性总糖含量最高,济麦22最低.封冻后20d东农705品系和济麦22叶片SOD失活,封冻后40 d东农冬麦1号叶片SOD仍有活性,调查期内济麦22各个部位SOD活性显著低于其他两个品种;封冻期东农冬麦1号叶鞘和分蘖节POD活性保持较高水平,东农705品系分蘖节POD活性较高,而叶鞘POD活性迅速降低,济麦22叶鞘和分蘖节POD活性均处于较低水平.

To analyze the distinctions in adaption during cold acclimation period among the cultivars which were different in the cold resistance, the physiological traits in the leaves and tiller nods of two kinds of winter wheat cultivars during the cold acclimation period were observed and measured. The results showed that the electrical conductivity of the cold resistant cultivar Dongnong Dongmai1 was lower than that of Jimai22; the content of proline and the soluble protein of both cultivars increased during the cold acclimation period, and the content of proline and the soluble protein in leaves and tiller nods of the Dongnong Dongmai1 was higher than that of Jimai22.

The changes of the fresh weight,dry weight,relative water content,electrical conductivity and the content of proline between the two cultivars Dongnong Dongmai1 and Jimai22 during the cold acclimation period were compared to analyze the physiological basis in winter hardiness of winter wheat.The results showed that the dry weight of Dongnong Dongmai1 was higher than that of Jimai22 during the cold acclimation period,when the temperature was lower than 0 ℃,the dry weight of Dongnong Dongmai1 still increased,but Jimai22 decreased.The relative water content of Jimai22 higher than that of Dongnong Dongmai1,the relative water content of Dongnong Dongmai1 decreased rapidly at October 29,and the relative water content of Jimai22 decreased rapidly at November 2.The content of proline in tiller nods of Dongnong Dongmai1 was higher than that of Jimai22.The relative electrical conductivity of Jimai22 was higher than that of Dongnong Dongmai1 during cold acclimation period.

The seedlings with 6 leaves of winter wheat cultivar "Dongnongdongmai 1" were treated in 5 combinations of temperature/ days based on temperature data for low temperature acclimation and over-winter period of winter wheat in 3 years,to reveal the change of proteins expressed in winter wheat cultivar "Dongnongdongmai 1" under different low temperature treatments.The changes of proteins in the seedling stems under soil surface were observed in different temperature treatments,and the results showed that there were significant changes in 17 protein spots by 4 low temperature treatments and 8 reappearing spots of those proteins were picked up for spectrum analysis.The 8 proteins were attributed to the processes of 26S protein dehydration,respiration,tricarboxylic acid cycle,chlorophyll synthesis,glyoxylate cycle,respectively,and of which one spot was cold resistant protein.Some speculations on the frozen resistance of the cultivar was proposed preliminarily by the amount changes and functions of the 8 proteins under different low temperature degrees.

The paper discussed the breeding strategy for yield breakthrough of spring wheat in Heilongjiang Province from the following 5 aspects. The aim was to solve the problem of the slow increasing of yield in spring wheat cultivars, the lower interest of planting wheat comparing with other crops, and the decline of spring wheat planting area in Heilongjiang Province, which arise the irrational structure of crop cultivation. From the yield components, genetic improvement of increasing kernel number in spring wheat should be prominently enhanced on breeding, which based on high harvest amount of spikes; the anti-lodging ability of wheat cultivars must be strengthened to avoid the risk of lodging as the weight of spikes increase; the yield breakthrough of spring wheat rested with enhancing the dry matter accumulation amount; coordinating the conflict on high and stable yield with yield and quality in the genetic improvement of wheat yield.

Protein extracting method,protein dissolution,protein loading amount and gel strip transfer were tested for the protein extracted from seedling rhizome of winter wheat cultivar Dongnong Winter Wheat No.1.The results showed that the loss of low abundance protein in TCA/acetone protein extracting process(T process) was less than that in urea/thiourea protein extracting process(N process) and the spots in protein map in T process were more than that in N process.The purer protein dissolved two times in the hydrated liquid could maintain higher voltage of 8000 volt by Isoelectric Focusing and Electrophoresis.The protein loading of 10mg by two times dissolution in hydrated liquid could obtain clear map with more protein spots and better separation effect.After adding 400μl 0.3% common agarose solution to glue surface and washing support film of gel strip with 200μl electric buffer,the gel strips could be transferred easily to second dimension glue surface and no air bubbles appeared between gel strips and glue surface.