不同育秧方式和插植密度下早籼稻群体动态结构的研究

于1996年早季研究了湿润与旱育秧方式在稀植(2苗/科)和多植(4苗/科)情况下超高产早籼品种特三矮2号在本田生长期的群体动态结构与产量表现。与多植比较,稀植的比叶重较大,中期叶面积系数较小,每穗颖花数较多;但有效分蘖数较少。与湿润育秧比较,旱育秧每科穗数较多,抽穗后群体保持较高的叶面积系数和干物质生产力;但生育期较长。旱育稀植的谷草比较高。     

不同育秧方式和插植密度下华南双季晚籼稻根系活力的初步研究

本试验于1995年晚季初步研究了水、旱育秧方式和不同插植密度下根系活力的变化趋势及与地上部生长发育的关系。结果表明:(1)旱育秧苗根系活力明显高于水育秧,根系活力与白根数、地上部苗体干/鲜重比值呈显著正相关,与褐根数、苗高、叶龄和百苗干、鲜物重呈负相关。(2)旱育单苗移植处理的根系活力在水稻整个生育过程中均高于旱育多苗移植处理,水秧单苗和多苗移植处理。生育后期根系活力与主茎功能叶片叶绿素含量和叶面积系数分别呈极显著正相关和正相关,旱育秧苗的这些特性有利于移植后叶片与分蘖的快速形成及生育后期延缓叶片衰老,提高籽粒充实度。同时提出,在水肥管理上应适当加大后期穗肥比例,改善光照条件和土壤的通气排水状况,以便充分发挥旱育稀植秧苗的增产优势。     

两种类型小麦品种分蘖成穗对群体环境的响应与调控

为探讨不同类型小麦(Triticum aestivum)品种分蘖成穗特性及对群体环境的响应, 寻求合理播种方式的调控参数, 在大田试验条件下, 对两类品种单株稀植与不同播种方式所构成的不同群体进行了对比研究。结果表明, 单株稀植时, 两类品种均具有较高的分蘖潜力, 中多穗型品种‘济麦20’和‘鲁麦14’单株平均成穗数为40.58和44.34个, 大穗型品种‘山农8355’和‘兰考矮早八’为24.33和23.20个, 成穗率存在着显著的基因型差异; 进入不同播种方式的群体环境后, 中多穗型品种每株平均成穗数降至3.37和3.85个, 降低率分别为91.70%和91.32%, 大穗型品种每株成穗1.82和1.36个, 分别降低92.52%和94.14%; 证明群体环境对分蘖成穗的影响比遗传因素更强烈, 且大穗型品种分蘖成穗特性对群体环境的响应较中多穗型敏感。播种方式可有效地调控群体结构, 条播的经济产量显著高于撒播, 条播行距配置对产量的影响因品种类型而异; 中多穗型行距在23.4-23.9 cm、大穗型在16.5-16.9 cm时产量最高; 撒播和窄行条播可有效地增加单位面积穗数, 提高挑旗和灌浆中期群体中、上层的光截获率, 而千粒重和穗粒数却随之降低。播种方式对挑旗后群体内部CO₂浓度有微弱的影响。     

高寒草甸矮嵩草种群的放牧中构件种群的反应特性

研究了不同放牧强度下高寒矮嵩草草甸建群种矮嵩草 (Kobresia humilis)构件种群的数量在放牧第四年 (1991年 )和停牧 1年后 (1993年 )的季节动态特性与反应。结果表明 ,随放牧强度增加 ,矮嵩草每分株中分蘖和叶片的数量增加 ,累积存活叶片数达到最大值的时间推迟。在各放牧处理下 ,分蘖数、生殖枝数和累积总叶数具有相同的季节动态过程。分蘖出生率分别在 5月中下旬和 8月下旬各有 1个高峰期 ,死亡率高峰在生长季末。叶片出生率和死亡率的周期与分蘖同步 ,叶片出生率和死亡率大小的变化也同步。矮嵩草分蘖和叶片群体的存活曲线类型分属“Deevey I”型和“阶梯”形 ,且不受放牧强度的影响。停牧 1年后 ,矮嵩草分蘖和叶片群体在放牧强度处理间的数量差异仍然存在     

水稻旱育稀植高产栽培的生理生态研究 Ⅱ. 早稻高产形成与生理生化特性

本研究结果表明,旱育秧苗移栽大田后仍能保持较强的生理生化优势,从分蘖期到乳熟期,旱育秧植株的抗坏血酸氧化酶、超氧化物歧化酶、过氧化物酶、过氧化氢酶、ATP酶和硝酸还原酶活性分别比对照高4.09～12.22%、8.22～19.68%、10.19～24.73%、2.77～22.36%、36.11～137.5%和26.11～135.2%, 丙二醛含量降低5.04～7.14%, 膜透性相应减少29～16.06%, 因而抗逆性强,秧苗移栽后返青快、分蘖早、成穗率高,叶片不早衰,干物质积累多,高产。     

高吸水性种衣剂对水稻旱育秧苗生长的影响

高吸水性树脂具有较强吸水保湿功能,使用高吸水性水稻种衣剂培育旱育秧苗,可以有效控制苗床水分和湿度,同时能缓释农药和肥料,增强秧苗抗逆性。试验表明,高吸水性种衣剂处理对水稻发芽率和发芽势无不良影响,且壮根、壮苗效果显著;能减少病害发生,保持旱育秧苗发根优势和分蘖优势,达到省工省时的目的。     

钾营养对水稻光合器功能的效应与谷粒产量的影响

水稻广陆矮四号和威优35盆栽试验的结果表明,施钾使叶绿体内基粒增多,Hill反应及光合磷酸化活力增强。分蘖末期在叶绿体反应液中添加KCl也可提高非环式光合磷酸化活力。适量施钾降低量子需要量可能与上述效应有关。钾使叶片超微结构改善:乳突大而多;硅化程度明显增加,故叶片更直立。叶水势及净光合率提高,两者呈直线正相关。灌桨期剑叶净光合率与谷粒产量呈直线正相关。     

水稻旱育稀植高产栽培的生理生态研究 Ⅱ.早稻高产形成与生理生化特性

本研究结果表明,旱育秧苗移栽大田后仍能保持较强的生理生化优势,从分蘖期到乳熟期,旱育秧植株的抗坏血酸氧化酶、超氧化物歧化酶、过氧化物酶、过氧化氢酶、ＡＴＰ酶和硝酸还原酶活性分别比对照高４．０９～１２．２２％、８．２２～１９．６８％、１０．１９～２４．７３％、２．７７～２２．３６％、３６．１１～１３７．５％和２６．１１～１３５．２％,丙二醛含量降低５．０４～７．１４％,膜透性相应减少２９～１６．０６％,因而抗逆性强,秧苗移栽后返青快、分蘖早、成穗率高,叶片不早衰,干物质积累多,高产．     

PP333对黑麦草生长和某些物质含量变化的影响

盆栽黑麦草施用PP333后,叶色深绿,株高降低．单株分蘖数及叶片数增多,根／冠比升高;植株地上部中的蛋白质含量增加,而根系中则有所降低;地上部光合产物向根系的运输加强。     

不同育秧方式和施肥水平下华南双季早稻秧苗生长特性的初步研究

本试验初步研究了华南双季早稻秧苗于不同育秧方式和施肥水平下的生长特点,结果表明:(1)旱育秧与湿润育秧秧苗在形态生长上的差异主要在于秧苗的叶片数不同,湿润育秧的出叶速度比旱育秧明显地快.(2)在有机质含量较高通气性能较优良的砂质壤土上进行旱育秧,基肥种类与施肥量在一定范围内时,具5片叶以下的旱育小苗的叶片数和株高无显著差异。(3)播后5天内的出苗率湿润育秧比旱育秧要显著地快而齐,而成秧率则各处理间有高有低,无明显规律可循,这与我们过去报道的结果趋势一致。(4)旱育秧移栽后的发根力比湿润秧要强,这种优势可维持到第9天才消失,再加上白/褐根的比例湿润秧要大,可能是导致旱育秧移栽后根系“爆发力”强、返青活棵快的重要因素。     

播种密度和基肥条件对晚籼稻旱育秧苗某些生理特性的影响

研究了1995年晚季不同播种密度和不同基肥对华南稻区晚籼稻旱育秧苗某些生理特性的影响。结果表明,在2种播种密度和5种基肥构成的10个处理中,秧苗叶龄、苗高和假茎宽等均无明显差异。在播种量为125g m-2条件下,虽然秧苗的总生长量较低,但其干/鲜重比值仍较播种密度为65gm-2略高;不同处理间的功能叶叶绿素含量(a b)、白根数/株和根活力呈显著差异,其中以沤熟有机肥和高无机肥用量作基肥的处理效果明显优于低无机肥用量作基肥的处理。因此,在进行旱育秧苗床培肥中,应注意以施用有机肥为主,适当补充无机肥,才能获得根系发达、活力强的健壮旱秧,为移栽后的叶蘖早发打基础。     

Seedling vigour and the early growth of transplanted rice (Oryza sativa)

Previous studies suggest that the positive response of transplanted rice (Oryza sativa L.) to nursery fertiliser application was due to increased seedling vigour or possibly to increased nutrient content. This paper presents results of two glasshouse experiments designed to test the hypothesis that seedling vigour was responsible for the response of transplanted seedlings to nursery treatments. The aim of the present study was to explore the concept of seedling vigour of transplanted rice and to determine what plant attributes conferred vigour on the seedlings. Seedling vigour treatments were established by subjecting seedlings to short-term submergence (0, 1 and 2 days/week) in one experiment and to leaf clipping or root pruning and water stress in another to determine their effect on plant growth after transplanting. Submerging seedlings increased plant height but depressed shoot and root dry matter and root:shoot ratio of the seedling at 28 days after sowing. After transplanting these seedlings, prior submergence depressed shoot dry matter at 40 days. Nursery nutrient application increased plant height, increased root and shoot dry matter, but generally decreased root:shoot ratio. Pruning up to 60% of the roots at transplanting decreased shoot and root dry matter, P concentration in leaves at panicle initiation (PI) and straw dry matter and grain yield at maturity. By contrast, pruning 30% of leaves depressed shoot and root dry matter by 30% at PI, and root dry matter and straw and grain yield by 20% at maturity. The combined effects of leaf clipping and root pruning on shoot, root and straw dry matter were largely additive. It is concluded that the response of rice yield to nursery treatments is largely due to increased seedling vigour and can be effected by a range of nutritional as well as non-nutritional treatments of seedlings that increase seedling dry matter, nutrient content, and nutrient concentration. Impairment of leaf growth and to a lesser extent root growth in the nursery depressed seedling vigour after transplanting. However, rather than increasing stress tolerance, seedling vigour was more beneficial when post transplant growth was not limited by nutrient or water stresses.     

Effects of Delaying Transplanting on Agronomic Traits and Grain Yield of Rice under Mechanical Transplantation Pattern

A delay in the mechanical transplantation (MT) of rice seedlings frequently occurs in Huanghuai wheat-rice rotation cropping districts of China, due to the late harvest of wheat, the poor weather conditions and the insufficiency of transplanters, missing the optimum transplanting time and causing seedlings to age. To identify how delaying transplanting rice affects the agronomic characteristics including the growth duration, photosynthetic productivity and dry matter remobilization efficiency and the grain yield under mechanical transplanting pattern, an experiment with a split-plot design was conducted over two consecutive years. The main plot includes two types of cultivation: mechanical transplanting and artificial transplanting (AT). The subplot comprises four japonica rice cultivars. The results indicate that the rice jointing, booting, heading and maturity stages were postponed under MT when using AT as a control. The tiller occurrence number, dry matter weight per tiller, accumulative dry matter for the population, leaf area index, crop growth rate, photosynthetic potential, and dry matter remobilization efficiency of the leaf under MT significantly decreased compared to those under AT. In contrast, the reduction rate of the leaf area during the heading-maturity stage was markedly enhanced under MT. The numbers of effective panicles and filled grains per panicle and the grain yield significantly decreased under MT. A significant correlation was observed between the dry matter production, remobilization and distribution characteristics and the grain yield. We infer that, as with rice from old seedlings, the decrease in the tiller occurrence, the photosynthetic productivity and the assimilate remobilization efficiency may be important agronomic traits that are responsible for the reduced grain yield under MT.     

Analysis of assimilate distribution by 3H-tracing during recovery period after rice seedling transplanting

In order to characterize assimilate distribution in rice (Oryza sativa L.) seedlings during recovery period after transplanting, the experiments were conducted by using ³H-isotope tracer technique with three rice hybrid combinations. The label introduced into the leaf sheath was distributed and redistributed to young roots, tillers, and young leaves, thus promoting these organs to grow at the initial stage after transplanting. During period from 10 to 30 days after labeling, ³H-assimilate redistribution occurred mainly from the sheath of the main stem; some radioactivity moved to tillers and roots emerged after transplanting. The activity and percentage of ³H-compounds transporting to rooting nodes and roots emerged after transplanting were higher in root-pruned plants than in control, indicating that growth of root-pruned seedlings more depended on the export of the compounds from the sheath of the main stem than growth of control seedlings.     

华南双季稻区早稻收割和晚稻移栽对褐飞虱种群动态的影响

为了阐明华南双季稻区早稻收割和晚稻移栽对褐飞虱种群动态的影响,2011年在韶关市采用田间调查与卵巢解剖的方法研究了双季早稻、双季晚稻、田埂杂草上褐飞虱的种群动态及虫源性质。结果表明:早稻收割后,早稻上大量的褐飞虱1～2龄若虫被淘汰,3龄以上若虫及成虫不断转移扩散致使附近晚稻秧田和杂草上褐飞虱虫量突增;晚稻移栽之后,杂草及晚稻秧田的褐飞虱又向新插秧的晚稻进行转移,但成为有效虫源的虫量较少,因此,早稻收割和晚稻移栽对褐飞虱种群动态造成了极为不利的影响,晚稻秧田和田埂杂草可作为褐飞虱转移过程中的流动栖息场所,在褐飞虱虫量转移中起着一定的作用。     

Density regulation during the regeneration of two monocarpic bamboos: self-thinning or intraclonal regulation?

Abstract. The population dynamics of two monocarpic bamboos, Sasa kurilensis and S. tsuboiana, were studied for more than 10 years after establishment following mass flowering. Both species show vigorous rhizomatous vegetative reproduction after growing up to maturity, but horizontal expansion in the seedling stage was much more vigorous in S. tsuboiana than in S. kurilensis. The pattern of changes in culm density in the two species was strikingly similar: culm densities of both species increased until they reached full-density states, after which they decreased in accordance with seedling growth. However, the mode of regulation in culm density was different. S. kurilensis seedlings were composed of only a few culms and scarcely extended their rhizomes during the observation period. Such poor lateral expansion resulted in asymmetric competition as observed in many non-clonal plants, and consequently their culm density decreased as a result of the mortality of genets due to self-thinning. In S. tsuboiana seedlings, the number of culms per genet increased considerably by frequent tillering and sprouting from rhizomes. However, after reaching full density state, the Bud Utility Ratio (BUR), (the proportion of the rhizome nodes with culms to the total number of rhizome nodes), decreased drastically. In this manner, S. tsuboiana regulated culm density intraclonally as is observed in the stable states of many clonal plants. Hence it is important for the understanding of the regeneration process in clonal species to clarify when and how their seedlings extend rhizomes during their growth.     

濒危树种钟萼木苗木年生长节律与适应性调查

对钟萼木Bretschneidera sinensis实播育苗、苗木物候期生长及不同试验点与不同培育方式的苗木生长进行研究。结果表明,该树种种子经催芽后发芽率达90%以上,苗木高与地径生长期主要在4～10月,10月后进入木质化状态,生长期较短是影响生长量的重要原因;高温与强光照对苗木顶芽与幼嫩叶产生灼伤影响,高温季节需进行遮荫;在高温高湿季节,易遭受病虫害为害,需加强病虫害防治。不同育苗方法表明,该树种大田裸根苗培育比容器苗更有利于苗木生长;不同生长类型的生长情况表明,良好的遗传个体在苗期表现良好的生长潜能。