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。     

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？…

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％,膜透性能相应减少２９～１６．０     

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。     

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．     

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。     

护苗种衣剂与护苗配套肥试验浅析

种植水稻,培育壮苗是关键,青枯病、立枯病、恶苗病等是水稻旱育秧苗期的重要病害。单纯依靠护苗种衣剂,虽能有效地防治水稻青枯病、立枯病和恶苗病,但防效不稳定。针对这种情况,我区采用护苗种衣剂加上护苗配套肥进行小面积试种,以期通过试验,为种植户推广和安全使用护苗种衣剂加护苗配套肥提供有力的直接数据,实现粮食增产增效。     

高吸水性淀粉的性能

本文综述了淀粉接技丙烯腈的皂化,金属离子氧化反应引发接技共聚的机理,皂化后淀粉接技丙烯腈的吸水性能与淀粉分子聚合度的关系,吸水性能与接技共聚物中聚丙烯腈聚合度的关系,高吸水性淀粉中所含水的特性以及淀粉、聚丙烯、及其共聚物的热行为。     

不同育秧方式和插植密度下晚籼稻冠层的透光率比较试验

以籼型水稻特三矮为材料,初步研究了水、旱育秧方式和不同基本苗插植密度下生长过程中晚季籼稻冠层的透光率。研究表明:单苗移植的透光率的下降速度高于多苗移植;旱育秧移植的透光率下降速度大于水育秧移植;遮阴生长的其透光率大于不遮阴的。自幼穗分化期起至黄熟期,四种育秧移栽方式的透光率基本相同。     

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。     

水稻旱育稀植高产栽培的生理生态研究Ⅰ.早稻肥床旱育秧苗素质及其生态生理特性

本研究表明 ,旱育秧床中土壤好气微生物总量高于对照 ,其中好气性固氮菌、纤维分解菌、氨化细菌、有机磷分解菌、亚硝酸细菌增加了 1 .40、2 0 .67、8.0 4、74.0 0、0 .69倍 ,除脱氢酶外土壤蛋白酶、纤维素酶、磷酸酶、尿酶和蔗糖转化酶活性比对照增加77.5%、51 .1 5%、47.1 2 %、43.59%、6.88% ,这有利于土壤物能转化 ,提高土壤养分的有效性 ,使旱育秧床土壤硝态氮、速效N、P、K比对照增加 2 7.9、2 .0 8、0 .97、0 .7倍 .同时还表明 ,旱育秧白根率高 ,根系氧化能力强 ,低节位分蘖多 ,并表现出强大的生理生化优势 ,淀粉酶、硝酸还原酶、ATP酶以及过氧化物酶、过氧化氢酶、超氧物歧化酶等保护酶含量增加 ,而丙二醛含量和膜透性比对照降低了 7.1 2 %和 43.42 % .     

壳聚糖-PVA水稻种衣剂在育秧上的应用研究

本文研究壳聚糖-PVA复合型水稻种衣剂对种子发芽率、成苗率、秧苗素质的影响以及对苗期病虫害的防治效果。结果表明,种衣剂对种子的发芽无不良影响,可提高秧苗素质,有效防止苗期病虫害发生。     

水分条件对干热河谷锥连栎种子萌发及幼苗早期生长的影响

对锥连栎(Quercus franchetii Skan)在4种施水量下的种子萌发、幼苗早期生长形态及生物量分配的响应特征进行了研究。结果表明,施水量对锥连栎的种子萌发过程具有显著影响。随着施水量增加,其种子萌发率、萌发指数以及萌发时间和萌发持续时间均呈明显的上升趋势,而萌发时滞和萌发速率系数呈下降趋势。锥连栎幼苗早期生长对施水量的适应幅度较大,每次施水4～12 mm时,幼苗均能存活,但生长状况存在明显差异,随着施水量的减少,幼苗生长和生物量的积累速度均出现显著减缓。同时,施水量对锥连栎幼苗生物量分配具有显著影响,随着施水量增加,幼苗根冠比呈显著下降趋势,表明在生物量分配上锥连栎幼苗具有极大的可塑性,施水量减少时,光合产物将向地下部分迁移,增加根冠比。     

Canola seed germination and seedling emergence from pre-hydrated and re-dried seeds subjected to salt and water stresses at low temperatures

Low soil temperatures and low water potentials reduce and delay the seed germination of canola (Brassica rapa L., B. napus L.) in western Canada. Germination is also very sensitive to the salinity effects of nitrogen fertiliser placed with the seed, especially when the seed bed is relatively dry. The effects of pre-hydration and re-drying treatment on canola (Brassica rapa L. cv. Tobin) seed germination and seedling emergence at 10°C subjected to either a water or salt stress were determined. Low water potentials, induced by polyethylene glycol (PEG 8000), low soil moisture, or high concentrations of salts, reduced both germination and seedling emergence, and increased the time to 50% germination and emergence of seeds at 10°C. At equal osmotic potentials, Na₂SO₄ was less inhibitory on low temperature germination than either NaCl or PEG, suggesting that the sulphate ion partially alleviated the inhibitory effects of low water potential. Solutions of NaCI produced more abnormal seedlings compared to Na₂SO₄, suggesting that NaCl was more toxic than Na₂SO₄ during seedling development. Pre-hydration and re-drying partially overcame the inhibitory effects of both low water potential and salts on seed germination and seedling emergence at 10°C. The seed treatment increased the germination rate in Petri dishes and seedling emergence from a sandy loam soil. Water potentials or soil water contents required to inhibit 50% germination or emergence at 10°C were lower for treated seeds compared to control seeds. Salt concentrations inhibiting 50% emergence were higher for treated seeds than control seeds. Neither treated nor control seeds produced seedlings which emerged if the soil water content was lower than 9% or when the soil was continuously irrigated with salt solutions of 100 mmol kg^-1 of NaCl or 50 mmol kg^-1 of Na₂SO₄. These results suggest that the pre-hydration and re-drying treatment did not lower the base water potentials at which seedling emergence could occur. Abnormal seedlings were observed in both treated and control seeds, particularly if the soil was watered with NaCl solutions; however, the seed treatment reduced the number of abnormal seedlings.     

Quantitative genetic analysis of seed vigour and pre-emergence seedling growth traits in Brassica oleracea

The ability of seeds to germinate and establish seedlings in a predictable manner under a range of conditions has a direct contribution to the economic success of commercial crops, and should therefore be considered in crop improvement. We measured traits associated with seed vigour and pre-emergence seedling growth in a segregating population of 105 doubled haploid Brassica oleracea lines. The germination traits measured were: mean germination times for unstressed germination; germination under water stress or germination after a heat treatment; and conductivity of seed leachate. The seedling growth traits measured were: seed weight; seedling growth rate; and seedling size at the end of the exponential growth phase. There were some correlations, notably among germination traits, and between seed weight and pre-emergence seedling growth. Heritability of the various traits was typically in the 10–15% range, with heritability of conductivity and mean germination time under water stress 25 and 24% respectively. Collectively the results indicate that germination and pre-emergence seedling growth are under separate genetic control. Quantitative trait loci analyses were carried out on all measurements and revealed significant loci on linkage groups O1, O3, O6, O7 and O9. We suggest that genes at these loci are important in determining predictable seed germination and seedling establishment in practice.     

湿地植物普通野生稻和慈姑之间的化感作用

普通野生稻（Oryzarufipogon）是现代水稻遗传育种的基础,已被列为濒危植物。本研究在实验室检测了普通野生稻与其常见伴生种慈姑（Sagittariatrifolia）之间的化感效应。研究发现普通野生稻和慈姑的根、茎、叶水浸出液对两物种的种子萌发和幼苗生长具有促进作用。普通野生稻种子经慈姑叶和普通野生稻根、茎和叶的水浸出液处理后,萌发率由对照的25%显著提高至39%~54%;慈姑种子经普通野生稻和慈姑各部分水浸出液处理后,萌发率由对照的不萌发提高至9%~81%。慈姑和普通野生稻各部分的水浸出液显著促进两者的幼苗伸长,但对根的生长表现出两种不同的效应：慈姑叶、叶柄和根的水浸出液以及普通野生稻叶的水浸出液对普通野生稻和慈姑根的生长具有抑制作用,而普通野生稻茎和根的浸出液促进慈姑根的生长。总体上,慈姑比普通野生稻对水浸出液更敏感。     

磁化水对小麦种子萌发、幼苗生长和生理特性的生物学效应

为研究磁化水对作物的生物学效应,本文详细分析了磁化水处理对小麦种子萌发、幼苗生长和生理特性的影响。研究结果显示：磁化水处理小麦的种子发芽参数与对照相比无显著差异;磁化水处理对小麦的株高、根长、地上部和根部鲜重等生长参数也无显著影响;同样,磁化水处理在叶片色素含量、可溶性糖、可溶性蛋白质含量、含水量、细胞汁液渗透势等重要生理特征参数方面也未显示出显著差异。此外,磁化水并未显著影响小麦叶片的光合作用。综上所述,磁化水处理对小麦种子萌发和幼苗生长无明显的生物学效应。     

Relative toxicity of arsenite and arsenate on germination and early seedling growth of rice (Oryza sativa L.)

Elevated soil arsenic levels resulting from long-term use of arsenic contaminated ground for irrigation in Bangladesh may inhibit seed germination and seedling establishment of rice, the country's main food crop. A germination study on rice seeds and a short-term toxicity experiment with different concentrations of arsenite and arsenate on rice seedlings were conducted. Percent germination over control decreased significantly with increasing concentrations of arsenite and arsenate. Arsenite was found to be more toxic than arsenate for rice seed germination. There were varietal differences among the test varieties in response to arsenite and arsenate exposure. The performance of the dry season variety Purbachi was the best among the varieties. Germination of Purbachi was not inhibited at all up to 4 mg l^–1 arsenite and 8 mg l^–1 arsenate treatment. Root tolerance index (RTI) and relative shoot height (RSH) for rice seedlings decreased with increasing concentrations of arsenite and arsenate. Reduction of RTI caused by arsenate was higher than that of arsenite. In general, dry season varieties have more tolerance to arsenite or arsenate than the wet season varieties.     

The effect of water-level fluctuations on seedling recruitment in an aquatic macrophyte Nymphoides indica (L.) Kuntze (Menyanthaceae)

We examined seed bank characteristics and seed germination and the survival of seedlings to understand the significance of water-level fluctuations on sexual regeneration in Nymphoides indica (L.) Kuntze. The seed bank existed throughout the pond. The longevity of the seed bank was more than 3 years. Seed germination started on the exposed mudflat as soon as water drawdown occurred. At the juvenile stage, exposed conditions were required for seedling growth and the young seedlings died under submergence. It was suggested that seedling establishment was successful after occasional water drawdown or along the water margin according to the period and pattern of water-level fluctuation. This study indicated the significance of the exposed mudflat at the water edge for seed germination and the growth of juvenile plants to the success of sexual regeneration in N. indica.     

Synthesis and biological activity of amino acid conjugates of abscisic acid

We prepared 19 amino acid conjugates of the plant hormone abscisic acid (ABA) and investigated their biological activity, enzymatic hydrolysis by a recombinant Arabidopsis amidohydrolases GST-ILR1 and GST-IAR3, and metabolic fate in rice seedlings. Different sets of ABA-amino acids induced ABA-like responses in different plants. Some ABA-amino acids, including some that were active in bioassays, were hydrolyzed by recombinant Arabidopsis GST-IAR3, although GST-ILR1 did not show hydrolysis activity for any of the ABA-amino acids. ABA-L-Ala, which was active in all the bioassays, an Arabidopsis seed germination, spinach seed germination, and rice seedling elongation assays, except in a lettuce seed germination assay and was hydrolyzed by GST-IAR3, was hydrolyzed to free ABA in rice seedlings. These findings suggest that some plant amidohydrolases hydrolyze some ABA-amino acid conjugates. Because our study indicates the possibility that different plants have hydrolyzing activity toward different ABA-amino acids, an ABA-amino acid may function as a species-selective pro-hormone of ABA.     

Effects of increased nitrogen deposition and precipitation on seed and seedling production of Potentilla tanacetifolia in a temperate steppe ecosystem

Background

The responses of plant seeds and seedlings to changing atmospheric nitrogen (N) deposition and precipitation regimes determine plant population dynamics and community composition under global change.

Methodology/Principal Findings

In a temperate steppe in northern China, seeds of P. tanacetifolia were collected from a field-based experiment with N addition and increased precipitation to measure changes in their traits (production, mass, germination). Seedlings germinated from those seeds were grown in a greenhouse to examine the effects of improved N and water availability in maternal and offspring environments on seedling growth. Maternal N-addition stimulated seed production, but it suppressed seed mass, germination rate and seedling biomass of P. tanacetifolia. Maternal N-addition also enhanced responses of seedlings to N and water addition in the offspring environment. Maternal increased-precipitation stimulated seed production, but it had no effect on seed mass and germination rate. Maternal increased-precipitation enhanced seedling growth when grown under similar conditions, whereas seedling responses to offspring N- and water-addition were suppressed by maternal increased-precipitation. Both offspring N-addition and increased-precipitation stimulated growth of seedlings germinated from seeds collected from the maternal control environment without either N or water addition. Our observations indicate that both maternal and offspring environments can influence seedling growth of P. tanacetifolia with consequent impacts on the future population dynamics of this species in the study area.

Conclusion/Significance

The findings highlight the importance of the maternal effects on seed and seedling production as well as responses of offspring to changing environmental drivers in mechanistic understanding and projecting of plant population dynamics under global change.