“以97鉴1”、“扬麦158”和“河南8679”分别代表特大穗型、大穗型和穗数型基因型材料，测定和分析了小（triticum aestivum L.）从小花分代至抽穗期穗部和叶片的内源植物激素水平。 幼穗中ABA高峰出现在雌雄蕊分化期至药隔形成期之间，出现时间则随穗型增大而推迟。 在减数分裂期前，特大穗型号幼穗中内源激素水平特别是ABA和CA1+3水平明显下降，但IAA/ABA及iPA/ABA的比值显著增加，与穗数型品种表现了完全不同的变化趋。此外， 特大穗型小麦幼穗中IAA和GA1+3水平在药隔形成期要高于叶片，在减数分裂期则已明显低于叶片，而穗数型小麦在减数分裂期穗中IAA与GA1+3的水平与叶片中比较接近，ABA水平甚至高于叶片。结果表明，药隔形成期至减数分裂期穗中ABA和GA1+3水平的急剧下降以及减数分裂期穗中极低的ABＡ和平ＧA1+3含量可能有利于小麦小花发育和大穗形成。

Accumulation of protein and starch in grain is a key procss determining grain yield and quality in wheat. Under drought or waterlogging, endogenous plant hormone levels will change and may have and impact on the yield and quality of wheat. In a greenhouse experimnet, four winter wheat (Triticum aestivum L.) varieties differing in grain protein conternt. Heimai 76. Wanmai 38. Yangmai 10 and Yangmai 9, were subjected to drought (SRWC=45～50%, DR). waterlogging (WL) and moderate water supply (SRWC=75～80%, CK), beginning form 4 days post-anthesis (DPA) to maturity. On the 10 (grain enlargemet stage) and 20 (grain filling stage) DPA. endogenous in sink and source organs of wheat plants by enxymc linked immunosorbent assay (ELISA). The patterns of hormonal changes were similar in four varieties. The ABA levels were much higher under DR and WL than under CK. Compared with CK, GA1+3 levels in whole-plant under DR and WL changed a little at 10 DPA, but markedly dectrease under DR and WL at 20 DPA. Changes of enodgenous IAA level under DR and WL exhibited a complicated pattern, depending on organs and growth stages. Particularly at the 20 DPA, the mean levels of IAA in roots. leaves and grains decreased significantly under DR and WL. In comparison with CK. ZR levels in all organs significantly decreased under DR and WL at both stages. The correlation analyses between yiclds and contents of starch and protein in grains and levels and rations of four hormones in source and sink organs indiated that the changes in yield and content of grain starch and protein under DR and WL were associated with the reduced IAa, ZR and GA, levels and elevated ABA level in plants, expecially in grains. It was proposed that the changed levels of endongenous hormones under post-anthesis DR and WL might indirectly affect protein and starch accumulation in grains by influencing the regulatory enzyines and rpocesses.

This study was undertaken to determine the time-course of floret primordium initation and degeneration in relation to thermal time after sowing in various cultivars and tiller position sof wheat (Triticum aestiveum L.). The field experiment was carried out on the experiment station of Nanjing Agricultural University of China. and included three sowing dates: carly planting of 30 September. middle planting of 30 October and late planting of 2 march and two wheat cultivars: winter type 'Jing 411' and spring type 'Yangmai 158'. Quadratic and linear relationships could deseribe floret initiation. degeneration and abortion in response to growing-degree-days after sowing for main stem and first and second tillers of middle planting plants of both cultivars. The floret fertility. The growing-degree-days from sowing to floret intiaion were significantly diffeent between the thre sowing dates and between the two cultivars. These results help quanitfy the dynamic processes of apical development and explain differcnes in floret development of wheat with different environments. cultivars and tiller development and explain the diffences in floret development of wheat with different environments. cultivars and tiller positions.

研究了小麦（Triticum aestimum L.）茎顶端不同类型原基分化的动态过程，以明确原基分化的综合模式，并建立了不同原基分化之间的定量关系。结果表明，小麦叶原基和苞叶原基分化与播后累积生长度日（GDD, growing degree days after sowing）的关系呈S形曲线，而小穗原基和小花原基为上升段抛物曲线，从分化模式看，苞叶原基具备营养器官原基特征；小穗和小花原基的分化进程能较好地反映基因型和生态条件对顶端发育的影响。小麦茎顶端原基分化的综合模式为由三段子模式构成的近似S曲线，叶原基数由基因型和环境条件共同决定，而苞叶原基、小穗原基和小花原基数以环境因子的影响为主。以平均热间距来衡量，适期播处理的叶片、苞叶和小穗原基分化速率最高；而小花原基数与小花分化持续期之间的数量关系最为密切。研究结果有助于提示和理解小麦茎顶端发育的生物学规律。

蔗糖向淀粉的转化是决定小麦籽粒产量的重要因素。田间条件下研究了两个小麦（Triticum aesivum L.)品种“鲁麦22”和“鲁麦22”和“鲁麦14”籽粒淀粉合成相关酶：蔗糖合酶（sucrose synthase, SS）、腺苷二磷酸葡萄糖焦磷酸化酶（ADP-glucose pyrophosphorylase, ADPGPPase）、可溶性淀粉合酶（soluble starch synthase, SSS）、束缚态淀粉合酶（starch granule-bound synthase, GBSS）的活性以及籽粒ATP含量的日变化。结果表明，上述酶活性呈现明显的昼夜变化特征，酶活性一般在白天较低，而在夜间呈较高活性，而籽粒ATP含量趋势相反。相关分析表明，白天较低的酶活性可能与气温超过其适宜温度有关。对籽粒淀粉合成相酶活性日变化的可能因子进行了讨论。