Study On The Relationship Among Endogenous Hormones And Vascular Structure And The Formation Of Spike From The Tillers Of Large Spike Winter Wheat Cultivar LanKao Aizao 8

Lankao Aizao 8 had been planted in the field of experiment from 2006 to 2008 to study the relationship between spike differentiation, endogenous hormones, vascula tissue structures and formation of Spike from the tillers under different densities. The main results were as follows:1. In this experiment, Great changes had been taken place in colony under different densities on Lankao Aizao 8.The tillers development is decreased with increasing of density, ears per plant is respectively:2.7ind,1.8ind,1.2ind under different densities.Lankao Aizao 8 shows strong tillering ability at two active tillering stage before winter and in spring,but the ultimate ears per plant still low.2. Spike differentiation process between simple stem showed that tillers lagGAsrd main stem at earilier growing stage in Lankao Aizao 8.The spike differentiation of the tillers were lagGAsrd with increasing of density and tillering positions.The tillers catch up with the main stem at florets initiation in D1(150×104hm-2) and D2(262.5×104hm-2) treatment,while the tillerⅡwas lagGAsrd in D3(375×104hm-2) treatment.Before the wheat jointing stage,The tillers will be ear bearing which they are spike differentiation process keep consistent with main stem,conversely,they will be contabescence.3. The content of GAs, IAA, ZR and ABA were determined in the first leaf of tillers and main stem,The results showed that:the content of GAs,IAA,ZR appears as culm>tillersI>tillersⅡ,the difference of content was larger between main stem and tillers before the wheat jointing stage.The content of ABA showed that tillersⅡ>tillers I>culm,this trend was found through the whole wheat jointing stage and the trend suddenly to enlarge at later jointing stage.The balance between endogenous hormones has great relationship with ear bearing and contabescense of tillers.Before jointing stage,the larger difference content of IAA/ZR, IAA/ABA, ZR/ABA between stem and tillers may be one of the reason for tillers contabescence.Besides,the low content of IAA/ABA, ZR/ABA go aGAsinst formation of spike from the tillers.4. The content of IAA,ZR.and ABA of basal part of stem and sheath in stem and tillers,the result showed that they have the same trendency with leaves,the difference of content was larger between main stem and tillers before the wheat jointing stage, the differentiation were increasing with increasing of density and tiller position.5. The content of endogeneous hormones was measured between stem and tillers at senescence stage of tillers.The result showed that There is a close relationship betwen the endogeneous hormones and the senescence of the tillers.The high content of GAs,IAA,ZR was good for tillers'suivival.they shown as culm>tillers I>tillersⅡin the same density.The percentage of tillers relative to main stem was decreased with increasing of tiller position.The content of ABA had increasing trend with increasing of density and tillering positions,the percentage of tillers relative to main stem had the same trend.The high content of IAA/ZR and the low content of IAA/ABA, ZR/ABA go aGAsinst formation of spike from the tillers.6. The paraffin serial transection methods was used in this experiment and studied the basal second and third length between the stem and tillers(Ⅰ,Ⅱ).The results were as follows:The formation of the vascular connection system between the ear and the stem was lagGAsrd with increasing of density and tillering positions.Non-earbearing tillers to compare with earbearing tillers,the edge of vascular and Parenchyma cells were sunken and not smooth.The stem wall thickness, the number of vascular bundles,vascular area,phloem area,vessel area were decreased with increasing of tiller position.and density.Vascular growth process was lagged.The indicators above generally shown as culm>tillers I>tillersⅡ.7. Meristem spuash of spike was observed between ear bearing-tillers and non-earbearing tillers, the results show as: there are large difference of cell division, The ear bearing-tillers cell division vigorous and morphogenesis themselves, non-earbearing tillers'cell stop division and go to dead.