| Psathyrostachys huashanica Keng(2n = 2x = 14, Ns Ns) belong to Gramineae?Triticeae ? Hordeinae ? Psathyrostachys Nevski, perennial herb,height40-60 cm, diploid cross-pollinated plant, basic chromosome numbers is 7, chromosome complement is Ns, and considered to be the donor of the Leymus,that it have two sets of chromosomes(NX), a wild relative of common wheat, which is only found on Huashan Mountain, a branch of the Qinling Mountain Range in Shaanxi province, China. It had many characters such early maturity, dwarf, high quality and high resistance to scab, stripe rust, take-all, and powdery mildew. While it is also noted for its resistance to cold, salinity, drought, and barren conditions, which is a useful gene pool for wheat improvement. The additional line of wheat and wild germplasm is a important genetic material to research evolution, gene interaction, gene expression, gene mapping. This article used wheat-P. huashanica hybrid progeny, through cytogenetic, genomic in situ hybridization(GISH), molecular marker(SSR?EST-SSR and EST-STS), anatomy, physiology, morphology analysis and agronomic traits evaluation and so on, to screening, identification a new additional line. The main results are as follows:1. Used cytogenetic, genomic in situ hybridization(GISH), successful identification a new wheat-P. huashanica 6Ns disomic addition line at mitotic and meiotic cytogenetic investigation and analyses indicated that the chromosome number and configuration. It has short height, big thousand weight and earlier mature characters, for three years, we performed continuous microscopic observations of the spike primordia from sowing until the harvest, which showed that the spike primordia of these line exhibited clear differences throughout the entire growth period, particularly focus on the earlier double-ridge to lemma primordium stage where the maturation of 25-10-3 occurred about 10 days earlier than that of its wheat parent 7182.2. Through the continuous three years(2010-2013) anatomy observation a complete set of wheat-P. huashanica disomic addition lines( 1 Ns-7 Ns), found that young ear differentiation development exists obvious difference between them, 6 Ns and 5 Ns additional lines in all material that young ear differentiation and development is the fastest, the second is 2 Ns and 3 Ns additional lines and the 4Ns additional lines is the latest. All early-maturing materials and late-maturing materials from the later single ridge or earlier double ridge to lemma primordium stage began to showed obvious differences, the precocious material has shorter differentiation time from double ridge to lemma primordium stage. So speculation that the advantageous to the development of young ear related genes on the 6 Ns, 5 Ns, 2 Ns and 3 Ns of-P. huashanica, while 4 Ns carry on bad genes that causing young ear delayed development. At the same time, it found that different Ns chromosomes of-P. huashanica presents significant positive and negative effects to wheat on photosynthetic, among them 1 Ns and 5 Ns additional lines showed obvious positive effect, the net photosynthetic rate reached 23.73 ±2.74(?mol/(m2·s), 23.19 ±8.29(?mol/(m2·s))respectively, compared with the parents wheat 7182, 15.73 ±2.00(?mol/(m2·s), extremely significant differences, while 3 Ns(11.10±0.63(?mol/(m2·s) and 6 Ns(11.64±1.57(?mol/(m2·s)) additional lines showed obvious negative effects, namely, highlights photosynthetic genes probably located on 1 Ns and 5 Ns chromosomes.3. Using a complete set of wheat-P. huashanica disomic addition lines(1 Ns-7 Ns), through two kinds of salt concentration(150 m M and 250 m M Na Cl) stresses at the germination and seedling stage, the study found that:(1)In the germination, salt tolerance materials have relatively high germination rate, under the 250 m M Na Cl treatment, the 7 Ns additional line(2-1-6-3)of the germination rate was 64%, 4 Ns additional line(24-6-3)the germination rate of 59%, the 5 Ns additional line(3-8-10-2) germination rate was 43%, and the root and leaf has a relatively good growth, and salt sensitive material, like Chinese spring, germination rate reduction under salt stress larger than before, and the germ and seed root growth limited seriously, parents wheat 7182 performance is relatively good, but the germination rate is low. Under the low and high concentrations of salt stress, 1 Ns additional line(12-3) has big biology characteristics, under the low concentration of salt stress, the bud is relatively long, than the root growth affected severely, but under the high concentration of salt stress, the shoot and root are affected seriously. 2 Ns additional line(3-6-4-1) and 3 Ns additional line(22-2) has the same results of 1 Ns additional line(12-3), while 6 Ns additional line(59-11) under the low concentration of salt stress, the buds grow relatively well, but at high concentrations, the seed root growth obviously suppressed, and salt resistant materials 4 Ns additional line(24-6-3), 5 Ns additional line(3-8-10-2), 7 Ns additional line(2-1-6-3) has similar results, good germinating rate relatively, but, the 7 Ns additional line(2-1-6-3)was the best of all.(2)At seedling stage, after 150 m M Na Cl salt stress, salt tolerance materials 7 Ns additional line(2-1-6-3)reached ?level, 4 Ns additional line(24-6-3),5 Ns additional line(3-8-10-2)reached? level; other materials were ?-? level, after 250 m M Na Cl salt stress, the 7 Ns additional line(2-1-6-3) level of salt tolerance drop to? level, 4 Ns additional line(24-6-3),5 Ns additional line(3-8-10-2)are still ? level, but the salt injury index increasing, other materials still ?-? level.( 3) Compared with salt sensitive material, salt tolerance materials had high above-ground and underground biomass, under the 250 m M Na Cl treatment, the 7 Ns additional line(2-1-6-3) of the above-ground of the fresh weight, dry weight, reached 3.75 g and 1.24 g, respectively, while wheat parents 7182 only had 2.78 g, 0.98 g, showed obvious differences. Relative conductivity and malondialdehyde(MDA) content of salt resistant material were small, after suffering salt stress, the electrolyte exosmosis more less, and cell membrane injury smaller, possess higher protective enzyme activity(POD, SOD), but the protective enzyme activity of all materials had various change, may be it associated with their own genetic differences. At the same time, the study found that the7 Ns additional line(2-1-6-3), 4 Ns additional line(24-6-3),5 Ns additional line(3-8-10-2)with the content of soluble protein and proline(Pro) content is relatively higher than others.(4)By root system scanner to scan the root found that salt stress after treat, the material in the root length, root surface area, root volume, root tip number quite different, and the increasing trend add with the salt concentration increasing.(5)Leaf and root of K+, Na+ and K+/Na+ is closely related to the material of salt resistance, the 7 Ns additional line(2-1-6-3), 4 Ns additional line(24-6-3),5 Ns additional line(3-8-10-2) of leaf and root has the high K + concentration, lower Na+, high K+/Na+, with the increase of salt concentration increasing trend.The above results showed that additional different Ns of the P. huashanica chromosomes, the salt resistance happened great changes, in terms of germination stage, integrated their germination rate under two kinds of salt concentration, salt tolerance level and relevant index analysis, largest contribution to the salt resistance was 7 Ns additional line(2-1-6-3), the second was 4 Ns additional line(24-6-3), 5 Ns additional line(3-8-10-2), could improvement the salt resistance of wheat significantly, may be the salt resistant genes located on these chromosomes. And 1 Ns(12-3), 2 Ns(3-6-4-1), 3 Ns(22-2), 6 Ns(59-11) chromosome additional lines were more sensitive to salt, may be the sensitive to salt-tolerant genes located on these chromosomes. Through further resistance to salt in seedling stage experiments, it showed that 7Ns(2-1-6-3), 4Ns(24-6-3), 5Ns(3-8-10-2) additional lines had better resistance to salt, basic consistent with the results of germination stage. |
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