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91.
水稻食叶类害虫等量损害系统与复合防治指标 总被引:5,自引:1,他引:4
稻纵卷叶螟Cnaphalocrocis.medinalis Guenèe中华稻蝗Oxya chinensis(Thunberg)稻苞虫Parnara guttatus (Bremer et Grey)是江苏地区水稻的主要食叶类害虫,取食水稻叶片,导致光合叶面积减少.剪叶模拟试验表明,水稻不同生育阶段叶面积损失率与产量损失率呈线性相关.其回归方程分蘖期、孕穗期、腊熟期分别为 D(It)=72.50759It1.15906、D(It)=141.61737It1.08002、D(It)=25.12434It1.00569.在叶面积损失率相同的情况下,产量损失率孕穗期>分蘖期>腊熟期.试验通过三种害虫的各龄取食量,不同生育阶段水稻叶面积及为害与损失率之间的关系,建立了不同生育阶段的经济允许损害水平(EILt).并根据各种害虫的相对潜在取食量,计算了校正等量损害系数,为制订复合防治指标提供了依据.实践证明:以等量损害为单位的复合防治指标有较大的实用价值,生态效益、经济效益、社会效益明显. 相似文献
92.
Anabaena sp., isolated from a rice paddy, was investigated for its nitrogen fixation as measured by acetylene reduction activity (ARA)
in P-limited continuous and light-limited semi-continuous cultures. Growth rate (μ) under P limitation was a function of cell
P content (q
p). Both the photosynthetic capacity (Pmax) and photosynthetic efficiency (α) increased with μ when expressed per cell, but not per unit chla. The ARA of steady-state cells under P limitation increased with μ and was linearly related to C-fixation rate. This was
apparently a consequence of the control of C-fixation by P limitation. In light-limited cells, steady state ARA, both at the
culture light intensity and in the dark, increased asymptotically with μ, but the activity in the dark was only about 51%
of that in the light. When the light level of steady-state cells grown at a high in intensity was switched to a low level,
ARA decreased exponentially with time. Dark ARA activity also showed a similar decline, but at much lower levels. Thus, ARA
depended not only on light history, but also immediate photosynthesis. Steady-state ARA at the ambient intensity or in the
dark showed a strong correlation with14C-fixation rate. ARA of light-limited cells showed the same light-saturation characteristics as their14C-fixation, with the same initial saturation intensity,I
k. The ratios of Pmax to the maximum ARA (ARAmax), and α to the slope of ARA (αara) were identical. A comparison of gross to net photosynthesis and N2 fixation suggested that there was little leakage or excretion of fixed C or N. 相似文献
93.
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95.
The effect of various experimental parameters upon the frequency of callus formation from cultured anthers of Oryza sativa has been investigated. Although certain medium components were found to be critical to callus formation, the concentration of these components had little effect upon the frequency of callus formation. The degree to which the callus formation frequency was influenced by cold pretreatment of the flowers was variable. Even though plants were grown under uniform conditions and flowers containing pollen in the microspore stage of development were selected for dissection, the frequency of callus formation varied nonrandomly between flowers. In experiments with populations of flowers in a physiological and developmental state favorable to callus formation 35% of plated anthers produced callus and at least 60% of these calluses gave rise to green plants. 相似文献
96.
Multiphasic accumulation of nutrients by plants 总被引:2,自引:0,他引:2
PER NISSEN NAND K. FAGERIA ANTONI J. RAYAR MOKHTAR M. HASSAN TANG VAN HAI 《Physiologia plantarum》1980,49(2):222-240
Seedlings of rice (Oryza sativa), soybean (Glycine max) and sour orange (Citrus aurantium) were grown for 20 to 125 days under controlled conditions in nutrient solutions wiht up to 16 different concentrations of NH4+, H2PO4-, K+, Ca2+, Mg2+ or Zn2+. Nutrient concentrations differed by up to 4 orders of magnitude (H2PO4- and Zn2+) and were kept constant or within certain limits by changing solutions daily. Dry weights and concentrations of N, P, K, Ca, Mg or Zn were determined for roots and tops (or roots, stems and leaves). The relationship between tissue concentration of an element and external concentration of the corresponding nutient ion was invariably multiphasic, with phases separated by sharp breaks or jumps. The kinetics of accumulation were similar to those of short-term uptake of the same ions. Reanalysis of previously published data (including data for Mn2+) for other plants yielded, similarly, bi- or multiphasic isotherms for accumulation. Accumulation patterns and growth were in several instances correlated, with separate phases coinciding with regions of poverty adjustment, luxury consumption and toxicity. Implications of multiphasic kinetics of long-term nutrient accumulation for membrane properties, fluxes and regulation include: (i) Membranes and uptake mechanisms must remain relatively constant throughout the life of the plant with respect to affinities for ions and concentrations at which transitions occur. (ii) Rate-limitation occurs at the plasmalemma of the root cortical cells. (iii) Uptake is at all times under multiphasic control by the external solution. 相似文献
97.
水稻内生细菌群落是反映植株内环境是否健康稳定的重要生物学指标,芽胞杆菌是防治水稻病害的重要生防微生物。为揭示芽胞杆菌浸种处理对水稻内生细菌群落结构的影响,采用Illumina MiSeq测序的方法对水稻内生细菌的16S rRNA基因进行测序,剖析了芽胞杆菌浸种处理对不同水稻组织内生细菌的微生态调控作用。结果表明,3种芽胞杆菌浸种处理可以提高水稻根和茎部内生细菌群落的丰富度和均匀度,降低叶部内生细菌群落的丰富度和均匀度,显著增加根部内生细菌群落多样性。变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)是水稻根部和茎部共有优势菌门,厚壁菌门和芽胞杆菌属(Bacillus)是叶部共有优势菌门和属。芽胞杆菌浸种处理显著提高了叶部内生厚壁菌门和芽胞杆菌属的相对丰度,增加了根系和茎部组织内生细菌的分类单元OTU(Operational Taxonomic Units)数量,对叶部组织影响不明显;降低了茎部和叶部中参与各种代谢通路的内生细菌丰度,显著增加了根部参与代谢通路的内生细菌丰度。因此,3种芽胞杆菌浸种处理可以显著改变水稻根部、茎部和叶部内生细菌群落结构,改善水稻生长的微生态环境。 相似文献
98.
气候变化对黑龙江省水稻障碍型冷害的影响 总被引:3,自引:0,他引:3
明确气候变化对黑龙江省水稻孕穗期和抽穗期障碍型冷害的影响,可为水稻安全生产提供科学依据。基于黑龙江省70个台站1971—2012年的气象资料和10个台站1980—2011年水稻生育期数据,结合水稻障碍型冷害指标,分析了气候变化对黑龙江省水稻障碍型冷害的影响。结果表明:(1)水稻孕穗期障碍型冷害1990s发生频率最低,2000s发生频率最高;抽穗期障碍型冷害1970s和1980s发生频率高,1990s和2000s发生频率低。(2)抽穗期障碍型冷害发生程度大于孕穗期障碍型冷害。(3)不同熟型水稻品种可种植北界逐渐北移东扩,极早熟、早熟和中熟品种可种植范围分别缩小了5、21和11个县(市),中晚熟和晚熟品种可种植范围分别扩大了14和23个县(市)。(4)随着水稻种植格局的变化,不同熟型水稻障碍型冷害均在1990s发生频率最低,2000s发生频率最高。 相似文献
99.
区域气候变化情景下气候变率对我国水稻产量影响的模拟研究 总被引:3,自引:0,他引:3
利用中国随机天气模型将中国区域气候模式RCM与作物模式CERES-Rice相连接,模拟了3种气候变率(0%,10%,20%)水平下未来气候(2050年,假定此时CO2浓度为550mg/L)对我国水稻主产区(广州,长沙,南京)灌溉水稻和雨养水稻在考虑CO2肥效与否条件下的产量,模拟结果表明;(1)气候变率对水稻产量的影响因经营方式和研究地区的不同而有差异,对灌溉水稻来说,气候变率对其产量有负面影响, 相似文献
100.