【作者】 李存福；

【导师】 韩建国；

【作者基本信息】 中国农业大学 ， 草业科学， 2005， 博士

【摘要】 本研究于2001-2003年在我国北方牧草种子的主产地内蒙古赤峰市宁城县,对无芒雀麦和紫花苜蓿种子繁殖特性及繁殖技术进行了全面、深入的研究,结果表明: 无芒雀麦的生殖枝主要由冬眠芽形成,当年生的春芽也能发育成生殖枝。分蘖时间集中在夏秋季节,春季分蘖比较少。无芒雀麦春季施用氮肥和春季施用氮磷钾肥,能增加第二年的生殖枝数量。疏枝能促进禾本科牧草的分蘖,提高翌年的生殖枝数量。 无芒雀麦种子的繁殖分配在11.8%～15.8%,田间管理措施对繁殖分配没有显著的影响。花序的繁殖分配在21%～30%,受生长环境的影响,变化比较大。紫花苜蓿个体的繁殖分配在3%～19%,变化幅度大,植株个体大小影响繁殖分配。 紫花苜蓿在降低种群密度的情况下,花序长度、花序数数量、荚果数量为超补偿效应,花序上的小花数和千粒重为等补偿效应,种子产量具有超补偿性和欠补偿性。在低密度下,植株中部和上部的荚果数量多;在较高的密度下,植株各部位的荚果数量明显减少。 无芒雀麦获得高的种子产量依赖于足够的生殖枝数量和较大的生物量。当无芒雀麦冠层叶面积指数为1,叶片分布均匀,22.5°天顶角直射辐射系数为0.76,散射辐射系数为0.5,平均叶倾角较大为78°,消光系数较小,能够获得较高的种子产量。紫花苜蓿密度较低,个体大小适中,枝条粗壮,夏生枝条少且生长缓慢,是获得种子高产的基础。 无芒雀麦的小穗主要分布在花序的下部,小穗上的小花数和种子数则在花序的上部最多。一般情况下花序下部的种子结实率高于上部。紫花苜蓿植株上下各部位,花序数量基本相同,呈均匀分布;花序上的小花数从枝条的下部到上部逐渐增多,枝条上的小花数则以中部居多,荚果在枝条的中部以上居多,下部较少。 紫花苜蓿种子发育过程中,种子含水量不断下降,接近成熟前,含水量下降较快;而种子干物质积累比较快,到成熟前10天左右,积累速度减慢。苜蓿种子进入黄熟期就具备比较高的发芽率。黄熟期到成熟,发芽率基本保持在同一个水平,而种子脱氢酶含量不断增加,到成熟时脱氢酶含量达到最大,种子的活力最高。苜蓿种子的平均发芽势40%,平均硬实率46%。种子发育过程中,发芽势缓慢升高升,硬实率平缓下降。发芽势和硬实率之间具有显著的负相关性。 对于无芒雀麦,春季施氮肥45～90kg/hm~2,秋春施氮肥135(95/40)kg/hm~2时,种子产量最高。行距50cm,保留30cm的植株,当年疏枝35～45cm时,对种子产量基本没有影响,疏枝后的第二年种子产量显著增加。返青前灌溉,能增加无芒雀麦的枝条数和花序上的小穗数,提高种子产量。 对于紫花苜蓿,群体密度为10株/m~2植株、140～170个/m~2枝条时,种子产量最高达1070kg/hm~2,比对照提高94.5%。紫花苜蓿施硼、钼和镁肥,能提高种子产量。施硼量3.5kg/hm~2,施钼量0.12kg/hm~2,施镁量15kg/hm~2时,种子产量最高。硼、钼、镁肥能提高苜蓿结实率,施硼肥后结实率最高达到27.9%。硼肥还能增加荚果中的种子数,增加幅度达20%。钼肥适宜用量下也能提高荚果中的种子数。更多还原

【Abstract】 The paper was conducted in a study for seed propagating characters and seed yields of smooth bromegrass, alfalfa in Chefeng, north-east of China in 2001-2003.The results showed that:Fertile tillers in smooth bromegrass arised from winter dormancy buds mainly, and gave birth to new buds formed in spring sometimes. Tillerng time was in summer-autumn briefly. The fertile tillers in next year were increased when applied nitrogen or N,P,K compound fertilizer. Thinning promoted gramineous tillering, enhanced fertile tillers in next year.Reproductive allocation of seeds of smooth bromegrass was 11.8-15.8%. It was a constant usually.21—30% reproductive allocation of panicle changes by application fertilizers and thinning. Reproductive allocation of alfalfa individual was in 3 - 19% that diversified due to the plant size.Over compensation belonged to raceme length, raceme number, pods of alfalfa as the plant density was decreased, equal compensation belonged to florets and 1000-seeds weight, over or lack of compensation belonged to seed yield.Optimal seed yield of smooth bromegrass depended on more fertile tillers and higher biomass, and for alfalfa relied on less plant density, strong spring shoots. It was a optimal seed yield for smooth brome canopy that leaf area equal to 1 approximately, leaf distribution was uniformity, transmission coefficient for radiation penetration in 25° was 0.76, transmission coefficient for defuse Penetration was 0.5, leaf angle was 78° ,and Extinction coefficient was less.Spikelets on panicle of bromegrass primarily located on low panicle. Florets and seeds per spikelet distributed on the upper panicle. Seed set was more on the low panicle than that on the upper panicle. Florets on low to upper raceme of alfalfa increased gradually, and florets laying on the mid raceme was the most.Seed moisture content of alfalfa decreased mildly during seed developing, declined more celerityly before mature. Dry matter increased gently in alfalfa seed developing and more quickly before ripe. After yellow fruit, germination of alfalfa was a constant that changed more less, but dehydrogenase increased and was the most in mature. Seed potency ascended and seed hard went down during seed developing mildly.Optimal seed yield of smooth bromegrass was got in 45-90kg/hm2 nitrogen applied in spring, 135(90/40)kg/hm2 nitrogen applied in autumn/spring, thinning 35-45cm per line with 50cm row space, and irrigating before recovering.Optimal seed yield of alfalfa was 1070kg/hm2 that was 1 times about more than the contrast as the plant density was 10 plants/m2, 140-170 shoots/m2. Application 3.5 kg/hm2Boron,0.12 kg/hm2 molybdenum,15 kg/hm2 magnesium got optimal seed yield. Seed set can be enhanced to 27.9% as applied boron.更多还原