羊草根际解磷细菌数量及解磷强度的研究

对松嫩平原羊草不同生育时期根际解磷细菌的数量和解磷强度的动态变化进行了研究。研究发现,羊草不同生育时期根际和非根际解磷细菌数量均呈现单峰曲线的变化趋势,并在果后营养期达最高峰;无论是无机磷细菌还是有机磷细菌,均呈现明显的根际效应;有机磷细菌数量都比无机磷细菌要多;羊草不同生育时期解磷细菌的解磷强度也呈现单峰曲线的变化趋势,除果后营养期之外,其他各时期无机磷细菌的解磷强度都高于有机磷细菌。     

大熊猫生态旅游对大熊猫及其栖息地的影响及对策分析

大熊猫生态旅游是一种独特的生态旅游方式,近年来发展迅速。本文结合生态旅游的知识阐述了大熊猫生态旅游的定义、特点以及开发现状,分析了大熊猫生态旅游对大熊猫及其栖息地产生的不良影响,并提出了科学开发大熊猫生态旅游的相关对策和建议。     

杨小舟蛾成虫和蛹自然发育进度研究

采用灯诱成虫和地面化蛹进度调查的方法,系统监测了1998,1999年杨小舟蛾成虫和2010年成虫及蛹的自然发育进度.结果表明:春季气温变化可显著影响越冬代和第1代成虫羽化高峰期的出现及第1,2代害虫的生长发育速度;降雨量偏多可导致害虫发育历期延长,种群数量显著下降;夏季异常气候会引起害虫种群数量发生显著变化,干旱高温的...     

季风常绿阔叶林不同恢复阶段附生维管植物多样性及分布

通过对云南普洱地区不同恢复阶段(恢复15年、30年和原始林群落)季风常绿阔叶林群落内附生维管植物的调查,分析了不同恢复阶段附生维管植物的物种丰富度、多度、分布和相似性关系,并探讨附生维管植物与宿主的关系。结果表明:(1)在0.81 hm²的调查样地中,共发现附生维管植物3 116株(分属9科20属22种);(2)原始林中附生维管植物的物种丰富度(17种)要显著高于恢复30年(7种)和15年(5种)群落;(3)原始林与不同恢复阶段群落中附生维管植物的物种组成有显著不同,恢复15年群落中的附生植物主要由蕨类植物组成,兰科植物是原始林附生植物的主要物种组成,有些物种仅出现在原始林中,可以作为季风常绿阔叶林恢复程度的指示物种;(4)原始林附生维管植物的多度要显著高于恢复阶段;(5)3个群落类型中的附生维管植物在水平方向都为聚集分布,恢复15年群落主要分布在0~5 m,原始林中分布可达到20 m;(6)原始林中附生维管植物物种丰富度和多度与宿主的胸径之间存在显著正相关,而2个恢复阶段森林中不存在相关性。     

Dry matter accumulation and partitioning in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) as influenced by potassium fertilization

The effect of potassium (K) supply on dry matter accumulation and partitioning of biomass between different among parts of cotton (Gossypium hirsutum L.) was determined under irrigated conditions. The treatments were four cotton cultivars (CIM-448, CIM-1100, Karishma, and S-12), four K rates (0, 62.5, 125, and 250 kg K ha⁻¹), and two K-fertilizer sources (K₂SO₄, KCl). Sequential harvests were collected at four stages of growth, viz first flower, peak flowering, first boll split, and maturity. The dry weights (DW) of vegetative and reproductive organs were determined. Maximum total DW was obtained at 125 days after planting, and then it declined because of leaf senescence at maturity. Cultivars differed significantly among themselves in the production of total DW and its partitioning between different organs. The addition of K fertilizer increased DW substantially at various stages of growth. Potassium fertilizer stimulated cotton plant to translocate resources towards reproductive organs rather than vegetative organs. Crop receiving 250 kg K ha⁻¹ allocated 77% more dry matter into reproductive organs. The K-sources produced a little effect on the allocation of DW in various parts of the plant. Maximum reproductive–vegetative ratio (RVR) was maintained by cv CIM-448 and minimum in cv CIM-1100. Data showed that a shift in DW allocation into reproductive organs was dependent upon sustained supply of K⁺ throughout the season. There were positive significant correlations (0.86, 0.71, and 0.90) between seed cotton yield and total DW, vegetative DW, and reproductive DW, respectively.     

再生稻产量形成的生理生态特性与关键栽培技术的研究与展望

本文介绍了目前我国再生稻的发展现状,从发育遗传和生理生态角度综述了近年来再生稻产量形成的研究进展,提出采用人工收割高留桩栽培再生稻时,选择头季分蘖力相对较弱、再生季再生力强的重穗型杂交籼稻品种(组合)易获高产;而采用机械化收割低留桩栽培再生稻时,选择具强低位芽再生力的杂交籼稻品种或感光性弱的重穗型杂交粳稻品种(组合)、籼粳交水稻品种(组合)易获高产。头季成熟期至再生季齐穗期根系活力的强弱,直接影响再生季产量的高低,再生季稻高产的前提是健壮的头季根系和一定数量新生根系的有效结合,这有利于促进腋芽的萌发成苗、增加每平方米穗数,是再生稻高产增产的关键。在此基础上,提出适时早播、畦栽沟灌、二次烤田、重施促芽肥、适高留桩的人工收割高留桩再生稻栽培技术,并从品种选择、再生季施肥、留桩高度等方面探讨了机械化收割低留桩蓄留再生稻的关键栽培技术及生理生态机制。最后提出了我国再生稻发展亟待解决的几个问题,认为当前轻简化的机收低留桩再生稻是我国再生稻发展的方向,并对机收低留桩再生稻的进一步研究作了展望。     

增硝营养对水稻不同生育时期生长及氮素吸收同化的影响

The effect of nitrate （NO3^-） on rice （Oryza sativa L.） growth as well as N absorption and assimilation during different growth stages was examined using three typical rice cultivars. Dry weight, yield, N uptake, nitrate reductase activity （NRA） in leaves, and glutamine synthetase activity （GSA） in roots and leaves during their entire growth periods, as well as the kinetic parameters of ammonium （NH4^＋） uptake at the seedling stage, were measured with solution culture experiments. Results indicated that addition of NH4^＋-N and NO3^-N at a ratio of 75：25 （NH4^＋＋NO3^- treatment） when compared with that of NH4^＋-N alone （NH4^＋ treatment） increased the dry weight of ‘Nanguang＇ cultivar by 30% and ‘Yunjing 38＇ cultivar by 31%, and also increased their grain yield by 21% and 17%, respectively. For the four growth stages, the total N accumulation in plants increased by an average of 36% for ‘Nanguang＇ and 31% for ‘Yunjing 38＇, whereas the increasing effect of NO3^- in the ‘4007＇ cultivar was only found at the seedling stage, in the NH4^＋＋NO3^- treatment compared to the NH4^＋ treatment, NRA in the leaves increased by 2.09 folds, and GSA increased by 92% in the roots and 52% in the leaves of the three cultivars. NO3^- supply increased the maximum uptake rate （Vmax） in the ‘Nanguang＇ and ‘Yunjing 38＇ cultivars, reflecting that the NO3^- itself, not the increasing N concentration, increased the uptake rate of NH4^＋ by rice. There was no effect on the apparent Michaelis-Menten constant （Kin） of the three cultivars. Thus, some replacement of NH4^＋ with NO3^-could greatly improve the growth of rice plants, mainly on account of the increased uptake of NH4^＋ promoted by NO3^-, and future studies should focus on the molecular mechanism of the increased uptake of NH4^＋ by NO3^-.     

不同生育期灌水和施氮对春玉米农田硝态氮迁移及产量的影响

通过对大田春玉米进行不同生育期灌水和施氮处理,研究了不同灌水和施氮对玉米农田硝态氮运移和产量的影响。结果表明:生物产量和籽粒产量及其灌溉水利用效率有随施氮量增加而增大的趋势。与全生育期灌水比较,任何生育期不灌水处理都造成生物产量和籽粒产量降低,而生育期不灌水处理增加了灌溉水利用效率,两个生育期不灌水处理的生物产量和籽粒产量的灌溉水利用效率最高。在春玉米生长阶段,拔节期,抽穗期和成熟期不灌水对生物产量影响显著,抽穗期不灌水、苗期与灌浆期不灌水、拔节期期和灌浆期不灌水处理显著影响籽粒产量。     

Response of Cotton to Irrigation Methods and Nitrogen Fertilization: Yield Components,Water‐Use Efficiency,Nitrogen Uptake,and Recovery

Efficient crop use of nitrogen (N) fertilizer is critical from economic and environmental viewpoints, especially under irrigated conditions. Cotton yield parameters, fiber quality, water‐ and N‐use efficiency responses to N, and irrigation methods in northern Syria were evaluated. Field trials were conducted for two growing seasons on a Chromoxerertic Rhodoxeralf. Treatments consisted of drip fertigation, furrow irrigation, and five different rates of N fertilizer (50, 100, 150, 200, and 250 kg N /ha). Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as indicated by the neutron probe.

Seed cotton yield was higher than the national average (3,928 kg/ha) by at least 12% as compared to all treatments. Lint properties were not negatively affected by the irrigation method or N rates. Water savings under drip fertigation ranged between 25 and 50% of irrigation water relative to furrow irrigation. Crop water‐use efficiencies of the drip‐fertigated treatments were in most cases 100% higher than those of the corresponding furrow‐irrigated treatments. The highest water demand was during the fruit‐setting growth stage. It was also concluded that under drip fertigation, 100–150 N kg/ha was adequate and comparable with the highest N rates tested under furrow irrigation regarding lint yield, N uptake, and recovery. Based on cotton seed yield and weight of stems, the overall amount of N removed from the field for the drip‐fertigated treatments ranged between 101 and 118kg and 116 and 188 N/ha for 2001 and 2002, respectively. The N removal ranged between 94 and 113 and 111 and 144 kg N/ha for the furrow‐irrigated treatments for 2001 and 2002, respectively.     

不同栽培模式下水稻各生育期光合生理指标的比较研究

为明确膜下滴灌与常规水作栽培的光合生理差异。通过对膜下滴灌和淹灌2种栽培模式下,4个水稻品系(T-04、T-43、T-66、T-69)在分蘖、孕穗、抽穗、乳熟、蜡熟期倒一叶的光合色素含量、光合-叶绿素荧光参数、抗氧化酶活性以及渗透调节物质含量等光合生理指标的测定分析。结果表明:滴灌模式下,4个参试材料在5个关键生育期的蒸腾速率(Tr)、气孔导度(Gs)、光合速率(Pn)均低于淹灌,胞间CO_2浓度(Ci)总体上略低于淹灌,大部分时期差异不显著(P0.05);叶绿素荧光参数、光系统Ⅱ有效量子产量(ΦPSⅡ)、最大荧光(Fm)、暗适应光系统Ⅱ最大量子产量(Fv/Fm)总体上低于淹灌,大部分时期差异不显著,最小荧光(Fo)高于淹灌,荧光淬灭系数(q P、NPQ)在2种栽培模式下差异不大,叶绿素含量、类胡萝卜素含量、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性总体上低于淹灌,超氧化物歧化酶(SOD)活性在2种栽培模式下差异不显著,丙二醛(MDA)、脯氨酸(Pro)含量总体上高于淹灌,可溶性蛋白(SP)含量总体上低于淹灌,可溶性糖(SS)含量差异不显著。水稻膜下滴灌栽培整个生育期均无水层覆盖,可能受到水分胁迫,导致其整个生育期大部分光合生理指标均低于淹灌。