水稻分蘖角度及其调控的生物学研究

水稻分蘖角度是创新水稻株型研究的关键因素之一,有关分蘖角度的研究一直是水稻高产栽培、育种及生理生态研究的重点。本文综述了水稻分蘖角度的遗传控制和有关环境生态因子、营养条件以及激素等对分蘖角度的影响,为杂种优势利用和株型改良相结合的高产水稻育种目标提供理论线索。     

外源赤霉素信号对甘蔗分蘖及其内源激素的影响

前期研究发现,外源GA信号影响了甘蔗分蘖进程。为了解GA信号对甘蔗不同分蘖时期叶片内源激素含量的影响,以综合性状优良的甘蔗主栽品种‘桂糖42号’为材料,采用不同外源GA信号调节剂对蔗种进行浸种处理,并以清水处理为对照（CK）,分别测定分蘖初期、盛期和末期+1叶（主苗+分蘖苗）中内源激素吲哚乙酸（indole-3-acetic acid,IAA）、赤霉素（gibberellins,GA）、乙烯（ethylene,ETH）、细胞分裂素（cytokinin,CTK）、脱落酸（abscisic acid,ABA）和油菜素内脂（brassinosteroids, BR）的含量,并分析它们之间的相关关系。结果表明：外源GA₃（gibberellic acid 3;GA生物合成促进剂）对蔗种浸种处理后,增加了分蘖期甘蔗分蘖叶片中IAA、GA和CTK的总体含量,提高了分蘖前期ETH含量和后期ABA含量;多效唑（paclobutracol, PP₃₃₃;GA生物合成抑制剂）处理后却增加了分蘖前期内源GA和ABA含量,提高了后期分蘖叶片中ETH含量,同时降低了CTK和BR含量。进一步的相关性分析发现,利用外源赤霉素信号促进剂处理蔗种后,甘蔗叶片内源激素IAA与GA、CTK和BR、CTK与GA均呈显著正相关;而ABA与GA呈显著负相关,与ETH呈显著正相关。可见,外源GA信号影响了甘蔗分蘖期叶片内源激素系统,促进生长的激素与抑制生长的激素达到动态平衡状态,最终导致了甘蔗分蘖的差异。甘蔗分蘖与植物内源激素含量密切相关,可通过施用外源激素来影响内源激素的含量,调控激素之间的动态平衡,达到提高甘蔗分蘖形成及其成茎的目的。     

水稻分蘖角度的研究进展

分蘖角度是构建水稻理想株型的关键因素之一,它通过影响水稻群体光能利用效率而影响水稻单位面积产量。综述了国内外对水稻分蘖角度的遗传、基因定位和克隆以及影响水稻分蘖角度因素的研究进展。     

行向对不同穗型水稻品种的影响

以直立穗型和弯曲穗型两种类型水稻为材料,研究了不同行向对水稻分蘖数、维管束和穗部性状的影响。试验结果表明:行向对群体分蘖数的影响较小,分蘖数主要由品种决定;不同行向处理对不同穗型水稻的维管束影响较小,但对穗部性状有一定的影响。     

行向对不同穗型水稻品种的影响

以直立穗型和弯曲穗型两种类型水稻为材料，研究了不同行向对水稻分蘖数、雏管束和穗部性状的影响。试验结果表明：行向对群体分蘖数的影响较小，分蘖数主要由品种决定；不同行向处理对不同穗型水稻的维管束影响较小，但对穗部性状有一定的影响。     

节水灌溉对寒地水稻群体生长特性的影响

试验研究了浅湿干灌溉、间歇灌溉、好气灌溉等3种大田节水灌溉方式对水稻群体生长特性的影响。结果表明,节水灌溉延迟了水稻分蘖进程,分蘖数较常规灌溉不同程度增加,增幅为27~54茎/m2;水稻成穗率较常规灌溉有所提高,增幅分别为3.2%、13.9%和12.8%;水稻根干质量和根冠比均高于常规灌溉。     

稻田耕作方式对抛秧稻分蘖特性的影响

早季在田间用管栽试验对免耕水稻和常耕水稻的分蘖发生、成穗和结实特性进行了比较。结果表明,免耕水稻分蘖发生和成穗数分别比常耕水稻多8.12%和6.40%,分蘖优势明显。免耕水稻的分蘖优势主要表现在低位优势,其3~5节位分蘖发生数、分蘖成穗数及籽粒产量均比常耕水稻的高,其3~5节位单株一次分蘖发生数、成穗数及籽粒产量的增加量分别占全部节位单株一次分蘖数、成穗数及籽粒产量的增加量的75.00%,155.56%和146.91%。     

水稻分蘖消长动态与产量的研究

本文通过田间试验,对水稻分蘖与产量的关系、影响水稻分蘖的有关因素进行研究。研究结果表明,水稻育苗播种量、栽植密度、移栽时期等因素均对水稻分蘖有直接影响,而且,水稻有效分蘖数越多产量越高。在影响分蘖的各个因子中,适宜的播种量为催芽籽300—350g／m^2;适宜的移栽规格为30cm×（16．5—20）cm;最适移栽期为5月20—28日。稀植栽培能充分发挥水稻固有的分蘖特性,促进个体发育,形成良好的群体结构和受光态势,有利于水稻分蘖的早生快发,提高有效分蘖率,提高产量。     

水稻穗整齐生长关键基因获揭示

正近日,国际重要期刊PLOSGENETICS上在线发表了上海交通大学生命科学技术学院梁婉琪研究员领导的研究小组的研究文章,首次报道了基因DWT1在控制现代栽培水稻穗整齐生长中的关键作用。水稻的生长形态如株型、穗型、种子粒型等都对水稻产量具有重要影响。水稻植株由主茎和多个分蘖构成,主茎和分蘖之间的穗整齐度是影响水稻产量的另一重要因素。不同于野生稻,现代栽培水稻在人类驯化过程中形成了穗整齐生长的特征,株内主穗和各分蘖穗在成熟时期高度较为一致,穗大小也更为接近。这一特征     

不同灌溉方式对水稻产量及产量构成因子的影响

通过多年不同灌溉试验,研究了不同灌溉方式对水稻产量及产量构成因子的影响。结果表明,常规淹水灌溉栽培使水稻分蘖高峰期提前,分蘖增多,株高增高;节水灌溉栽培、极度节水灌溉栽培使水稻分蘖高峰期后移,分蘖减少,株高降低,生育期推迟。在常规淹水灌溉、节水灌溉、极度节水灌溉三种灌溉栽培下平均穗长递减。常规淹水灌溉栽培、节水灌溉栽培对水稻单位面积收获穗数和平均每穗实粒数影响不大;极度节水灌溉栽培对水稻单位收获穗数和平均每穗实粒数影响较大。节水灌溉栽培、极度节水灌溉栽培使水稻平均千粒重和平均结实率较高;常规淹水灌溉栽培反而使水稻千粒重和结实率降低。常规淹水灌溉栽培、节水灌溉栽培条件下水稻平均产量接近,说明水稻在栽培过程中适度的节水,对产量没有影响;极度节水灌溉栽培条件下水稻平均产量较低,说明节水过度对水稻的产量影响很大,降低了水分利用效率,反而成为低效用水。     

Factors in the Reduction in Grain Number in Winter Wheat by Early-Sowing in Yamaguchi

Abstract

Grain number per spike of wheat is lower in early sowing than in the conventional standard cultivation in Yamaguchi, Prefecture, Japan. Components of the grain number per spike in five cultivars were analyzed with respect to temperature during the spike development period throughout three growing seasons 2001/2002, 2002/2003 and 2003/2004 to find the cause of the problem of early sowing cultivation. The plants sown in early-October and late-November were called the early sown group and the standard group, respectively, in the following. Three of the five cultivars, Hokushin, Akitakko and Nanbukomugi, showed a strong winter habit, which requires very cold temperatures for spike differentiation. The other two cultivars, Iwainodaichi and Airakomugi, had a moderate winter habit. Grain number per spike and grain yield were decreased by early-sowing (compare with the standard group) in almost all cultivars throughout the three growing seasons. The three cultivars which had a strong winter habit had fewer spikelets per spike in the early-sown group than in the standard group. The other two cultivars which had a moderate winter habit had fewer grains per spikelet in the early-sown group. The higher the temperature during the spikelet formation phase, which is from flag leaf initiation to terminal spikelet initiation, the higher the number of spikelets per spike in the standard group. The spikelet number per spike in the early-sown group increased with the increase in productive tillers under fertile conditions. Such conditions also increased the grain number per spike.     

Allelopathy in Agroecosystems in Spain

Summary

This paper reviews the effects of allelopathic interactions in agroecosystems in Spain on plant physiological activity and their ecological advantages. The phenological stage of growth of donor plants and the effective allelochemicals in the soil solution while studying the role of phenolic compounds were highlighting. Finally possible future prospects and conclusions regarding weed control by allelochemi-cals under integrated crop management strategies are discussed.     

2009年中国稻米市场分析及2010年展望

以翔实的资料对2009年中国稻米生产、消费、进出口、供求平衡、库存、价格走势、购销政策和国际稻米供求等情况进行了全面地分析,对影响2010年稻米市场价格走势的各种因素进行了深入研究,并在此基础上对2010年我国稻米市场价格走势进行了预测,结论是我国稻米价格仍呈上行趋势。     

Advances in Variable Rate Technology Application in Potato in The Netherlands

Precision agriculture is a farming management concept based on observing, measuring and responding to inter- and intra-field variability in crops. In this paper, we focus on responding to intra-field variability in potato crops and analyse variable rate applications (VRAs). We made an overview of potential VRAs in potato crop management in The Netherlands. We identified 13 potential VRAs in potato, ranging from soil tillage to planting to crop care to selective harvest. We ranked them on availability of ‘proof of concept’ and on-farm test results. For five VRAs, we found test results allowing to make a cost-benefit assessment. These five VRAs were as follows: planting, soil herbicide weed control, N side dress, late blight control and haulm killing. They use one of two types of spatial data: soil maps or biomass index maps. Data on costs and savings of the VRAs showed that the investments in VRAs will pay off under practical conditions in The Netherlands. Savings on pesticide use and N-fertilizer use with the VRAs were on average about 25%, which benefits the environment too. We foresee a slow but gradual adoption of VRAs in potato production. More VRAs will become available given ongoing R&D. The perspectives of VRAs in potatoes are discussed.     

我国高粱育种研究进展

对我国高粱育种的主要途径和研究方向进行了概述,针对目前高粱产量徘徊现象,提出了高粱超高产育种设想,并对其技术路线进行了探讨。     

Diurnal changes in net photosynthetic rate in potato in two environments

Summary Diurnal changes in net photosynthetic rate were measured in a furrow-irrigated potato crop and in a riverbed crop where the water table was always maintained at 20–28 cm from the soil surface. In the irrigated crop, the photosynthetic rate during mid-afternoon was about half the peak rate observed at noon. This reduction was accompanied by a near tripling of stomatal resistance, a 45% reduction in transpiration, and a 5-fold increase in the difference between leaf and air temperatures. No such changes were observed in the riverbed crop where the photosynthetic rate remained nearly constant at about 0.9 mg m⁻² s⁻¹ between 9 a.m. and 4 p.m. Tuber yield in the riverbed crop was about 30% higher than in the irrigated crop.     

我国干热区甘蔗抗旱植蔗主要问题研讨

我国干热蔗区是我国甘蔗糖业的重要生产基地,蔗区光热资源丰富,唯降水分布不均成为植蔗生产的主要限制因子;根据蔗区植蔗特点和甘蔗需水规律,苗期抗旱是干热蔗区抗旱植蔗的关键,保证较多的总苗数和足够的生长量是苗期抗旱植蔗需解决的关键技术难题,制定相应的苗期抗旱植蔗栽培技术措施是解决该难题的重要保障;该观点为我国干热蔗区植蔗生产、甘蔗引育种提供理论和技术支持。     

棉花体细胞无性系变异的研究进展

体细胞无性系变异是一种重要的细胞工程育种技术,其应用于棉花育种的前提是建立高效的组织培养诱导再生植株体系.本文简要综述了棉花离体诱导植株再生研究的现状,重点讨论了棉花体细胞无性系变异的表现、利用方法及机理,提出了当前研究存在的问题并对今后的研究进行了展望.