温室黄瓜干物质分配与产量预测模拟模型初步研究

依据温室黄瓜(Cucumis sativus)器官生长与温度和辐射的关系,建立了基于分配指数和采收指数的温室黄瓜干物质分配与产量预测模拟模型,并利用不同品种和基质的试验资料对模型进行了检验。结果表明,模型对黄瓜地上部分干重、根干重、茎干重、叶干重、果实干重的预测结果与1∶1直线之间的R²分别为0.98,0.73,0.83,0.92,0.94;RMSE分别为232,6.8,157.6,173.9,196.8 kg/hm²。模型对黄瓜产量的预测结果与1∶1直线之间的R²为0.80,RMSE为7526.4 kg/hm²。本模型对不同基质、品种的黄瓜干物质分配和产量的预测值与实测值符合度均较高,说明本模型的普适性较好。模型不仅能较好地预测中国现有生产水平下温室黄瓜的干物质分配及产量,而且可以为实现中国温室黄瓜生产环境优化调控和模式化栽培管理提供决策支持。     

Effect of cadmium toxicity on micronutrient concentration,uptake and partitioning in seven rice cultivars

Heavy metal uptake, translocation and partitioning differ greatly among plant cultivars and plant parts. A pot experiment was conducted to determine the effect of cadmium (Cd) levels (0, 45 and 90 mg kg^?1 soil) on dry matter yield, and concentration, uptake and translocation of Cd, Fe, Zn, Mn and Cu in seven rice cultivars. Application of 45 mg Cd kg^?1 soil decreased root and shoot dry weight. On average, shoot and root Cd concentrations and uptake increased in all cultivars, but micronutrients uptake decreased following the application of 45 mg Cd kg^?1. No significant differences were observed between 45 and 90 mg kg^?1 Cd levels. On average, Cd treatments resulted in a decrease in Zn, Fe and Mn concentrations in shoots and Zn, Cu and Mn concentrations in roots. Differences were observed in Cd and micronutrient concentrations and uptake among rice cultivars. Translocation factor, defined as the shoot/root concentration ratio indicated that Cu and Fe contents in roots were higher than in shoots. The Mn concentration was much higher in shoots. Zinc concentrations were almost similar in the two organs of rice at 0 and 45 mg Cd kg^?1. A higher Cd level, however, led to a decrease in the Zn concentration in shoots.     

Organ-specific allocation pattern of acquired phosphorus and dry matter in two rice genotypes with contrasting tolerance to phosphorus deficiency

ABSTRACT

Our earlier study demonstrated that the landrace of Japonica rice, Akamai exhibits low-P (phosphorous) tolerance mechanisms compared to the conventional type cultivar, Koshihikari. The present study examined the genotypic difference of yield, plasticity of root growth, and internal utilization of acquired P (allocation pattern of biomass and P among different vegetative and reproductive organs) of two contrasting cultivars in response to P-deficiency. Each cultivar was grown until maturity with (+P) and without (–P) P supply in pots (two plants per pot) filled with 15 kg of Regosol soil. Grain yield and yield components were determined along with biomass and P accumulation in different vegetative and reproductive organs. To assess the plasticity of root growth, the soil column in the pot was divided into two equal portions (upper and lower soil layers) in which the root dry weight and length were measured separately. Among the investigated yield components, the number of filled grains per panicle was the key parameter determining genotypic differences of grain yield of two cultivars. P-deficiency had a marked influence on grain filling of Koshihikari where the filled grain percentage under –P condition was reduced by 29% compared to that under +P condition. However, the respective reduction for Akamai was only 11%. Low-P tolerance ability of Akamai imparts a yield advantage over Koshihikari under P-deficient conditions because of the production of the higher number of filled grains per panicle. Akamai explored both upper and lower soil layers of the pot more efficiently in search of P through greater root biomass and length. Akamai grown under P-deficient conditions had remarkably lower P concentrations in less active vegetative tissues (partly and fully senesced leaves) than those of Koshihikari; whereas, more active organs (green leaves and panicles) contained a greater amount of P. Akamai’s higher plasticity to external P availability can be a genetic resource for developing low-P tolerant, high-yielding rice genotypes suitable for predicted future P-limited environments.     

人工环境昼夜温差对番茄营养物质和干物质分配的影响

为了研究番茄各器官中可溶性糖和蔗糖含量、叶片中游离氨基酸和可溶性蛋白含量、不同器官干物质分配比例及番茄果实品质对昼夜温差的响应规律,该研究以番茄品种"金冠5号"(Solanum lycopersicum cv.Jinguan5)为试材,于2012年9月-2013年7月在南京信息工程大学设计日均气温为18和25℃,昼夜温差(difference between day and night temperature,DIF)为12℃(白天24℃/晚上12℃,31℃/19℃)、6℃(21℃/15℃,28℃/22℃)、0(18℃/18℃,25℃/25℃)共6个处理的人工环境控制试验,结果表明:日均气温18℃时,叶片中的游离氨基酸总量和可溶性蛋白、果实中的可溶性糖和蔗糖含量均以12℃温差处理最高,0温差处理最低;而果实中的有机酸含量以12℃温差处理最低;日均气温25℃时,果实中的可溶性糖和蔗糖含量以6℃温差处理最高。叶片中的游离氨基酸总量、幼果期和采收期叶片的可溶性蛋白含量均以6℃温差处理最高。维生素C、可溶性蛋白和番茄红素在日均气温18℃时则与有机酸含量趋势相反。干物质在果实中的分配比例在日均气温18和25℃时,均以6℃温差处理最大,12℃温差处理最小。研究认为在日均气温18℃条件下,昼夜温差0~12℃范围内,昼夜温差越大,果实中可溶性糖、蔗糖的积累越多,游离氨基酸和可溶性蛋白含量越高,果实品质更佳,在日均气温25℃条件下,以6℃温差处理下果实内在品质最佳;相同昼夜温差,25℃日均气温处理下的果实内在品质优于18℃日均气温处理;在最适温度范围内,适当增加昼夜温差有利于可溶性糖、蔗糖和干物质向果实中转移,温差过高或过低不利于果实营养物质及干物质积累。     

Effect of shade and level of fertilizer application on nutrient uptake and dry matter partitioning in cocoyam (Xanthosoma sagittifolium L.)

The effect of shade and fertilizer application on nutrient uptake and dry matter (DM) partitioning in cocoyam was evaluated by growing the plant under different levels of shade and fertilizer application at Forest and Horticultural Crops Research Centre, Kade, within a period of 9 months. The shade levels used were 80%, 70%, and 50% shade, and full sunlight exposure. The fertilizer rates used were 112 kg/ha nitrogen, phosphorus and potassium (NPK) (15-15-15 120 kg/ha NPK (15-15-15) in a form) of mineral fertilizer, 112 kg/ha NPK organic fertilizer and no fertilizer (control). The split-plot design was used with shade levels as the main plot factor and fertilizer levels as the sub plot factor. The interaction effect of shade and fertilizer had a significant effect (p ≤ 0.05) on DM of cocoyam leaves, petioles, corm, and cormels as well as nutrient accumulation in plant parts. Cocoyam leaves of plants grown under 50–70% shade stored significantly higher (p ≤ 0.05) quantities of nutrients (1.51 ppm of N, 6.61 ppm of P, and 53.10 ppm of K) and accumulated more DM (71.30 g) than leaves of plants grown under full sunlight exposure which accumulated 1.37 ppm of N, 4.31 ppm of P, 26.06 ppm of K, and 30.7 g DM, at the two rates of the chemical fertilizer application. Under full sunlight exposure, significantly higher amounts of DM were accumulated in the corms and cormels at mineral fertilizer level of 112 kg/ha. At mineral fertilizer rate of 120 kg/ha, nutrient accumulation was significantly higher (p ≤ 0.05) in the corm and cormels (1.72 ppm of N and 7.72 ppm of P) of plants grown under full sunlight exposure than those grown under 70% shade level (0.6 ppm of N and 2.94 ppm of P). Nitrogen and phosphorus accumulation was significant in the petioles of plants grown under the 70% shade level at fertilizer rate of 120 kg/ha. It is recommended that cocoyam be grown under 50–70% shade at a fertilizer rate of 112–120 kg/ha for leaf production and under full sunlight exposure at 112 kg/ha (NPK) for cormel production.     

Nutrient uptake and removal by Christmas tree harvest

Writing nutrient management plans for Christmas tree production requires accurate values for nutrient removal and harvest records. Freshly cut trees of each of Norway spruce (Picea abies), Canaan fir (Abies balsamea var. phanerolepis), and Douglas fir (Pseudotsuga menziesii) were collected in December 2005. Minimum, maximum, and mean cut tree size measurements were documented. Nutrient contents were calculated and there were no significant differences in nutrient uptake values among species. In a spacing of 1.5 m × 1.5 m (4302 trees per hectare), a clear-cut harvest would remove on average (kg/ha) 560 nitrogen (N), 60.87 phosphorus (P), 168 potassium (K), 243.51 calcium (Ca), 37.75 magnesium (Mg), 28.25 sulfur (S), 0.54 boron (B), 3.39 iron (Fe), 4.74 manganese (Mn), 0.11 copper (Cu), 2.79 zinc (Zn), 2.92 aluminum (Al), 105.85 chlorine (Cl), 0.02 molybdenum (Mo), and 1.44 sodium (Na). Except for Mn and Na, nutrient removal increased linearly as dry weight of whole tree increased.     

不同水稻品种获取氮能力的差异

采用溶液培养方法研究了不同水稻品种获取氮能力的差异及其原因。结果表明,在不同供氮水平下,不同水稻品种吸氮能力差异显著。随着供氮水平的提高,南光、豫粳7号、黔育421和武运粳7号的氮积累总量增加显著,说明这4个水稻品种对氮的响应度高;而桂单4号、ELIO、云粳38和4007的氮积累总量增加不显著,说明它们对氮的响应度低。对氮响应度高的4个水稻品种的平均吸氮速率随着供氮水平的增加其增幅显著,而其总根长的变化幅度则较小。水稻氮积累总量与总根长和平均吸氮速率的相关关系的分析结果表明,平均吸氮速率对水稻苗期获取氮能力的贡献率大于其总根长的贡献率。     

Nitrogen application in direct wet-seeded rice under alternate wetting and drying irrigation condition: Effects on grain yield,dry matter production,nitrogen uptake and nitrogen use efficiencies

Yield, dry matter production, nitrogen (N) uptake and nitrogen use efficiency (NUE) of Bangladesh Rice Research Institute (BRRI) dhan29 were investigated during two consecutive dry (Boro) seasons of 2009–10 and 2010–11. The experiments were set up in a randomized complete block design with three replication having six nitrogen (N) levels of 0, 40, 80 120, 160 and 200 kg ha^?1. Nitrogen fertilization increased yield characters, dry matter production and N uptake. The economic optimum rate of N was 166 and 155 kg ha^–1 in first and second year, respectively, with corresponding yield of 7.1 and 6.5 t ha^?1. NUEs were higher in the first year, decreased with increasing N rates in most cases. Gross return over fertilizer reached the highest Tk 692 in 2009–10 and Tk 489 in 2010–11 with 160 kg N ha^–1. The results suggest that BRRI dhan29 should receive an average of 160 kg N ha^?1 for economic optimum yield.     

氮肥运筹方式对杂交水稻干物质积累和产量的影响

以杂交中籼稻Ⅱ优2027和36优959为材料,在施氮量240 kg/hm2条件下,研究氮肥运筹方式对杂交水稻产量及构成因素和干物质积累的影响。结果表明,水稻产量、干物质积累随氮追肥用量的合理提高而增加,但后期施氮比例过高则不利于产量、干物质积累和形成良好的构成因素。氮肥运筹以4∶3∶3(基肥∶分蘖肥∶穗肥)较为合理,两个水稻品种产量最高,分别达8314.8 kg/hm2和9399.5 kg/hm2。干物质积累和根干重最高,生育后期干物质积累强度最大。     

优质、高产、多抗早籼中熟杂交稻新组合金优253的选育及应用

利用田东野生稻、IR36、IR2061、IR24、古154等五个各具显著优异性状的育种材料进行单交、复交,将各自优异性状综合到一个新个体中．从而选育出强优广谱恢复系测253,然后用其与优质不育系金23A配制成优质、高产、多抗早籼中熟杂交稻新组合金优253。该组合于2000年12月通过了广西农作物品种审定委员会审定,目前正在广西、湖南、江西、福建及越南迅速大面积推广应用。深受群众欢迎,前景十分广阔。     

氮素对温室黄瓜开花后干物质分配和产量影响的模拟研究

了解氮素对干物质分配和产量的定量影响是实现温室黄瓜氮肥优化管理的前提.该研究通过黄瓜雌性无限生长型品种"戴多星"(Cucumis sativas.'Deltastar')不同定植期和开花后不同氮素处理试验,定量分析了氮素施用水平对该类型黄瓜开花后干物质分配和产量的影响,并建立了开花后分配指数和采收指数与盛果期叶片氮浓度的关系方程.在此基础上,建立了氮素对黄瓜开花后干物质分配和产量影响的预测模型,并用独立的试验数据对模型进行了检验.结果表明,模型对茎干物质量、叶干物质量和果实干物质量及黄瓜产量(鲜质量)预测值与实测值之间基于1:1直线之间的决定系数R2分别为0.945、0.943、0.990、0.955;相对预测误差RE分别为13.0%、12.3%、9.2%、16.8%.本模型可预测不同氮素水平下温室黄瓜地上部各器官干物质量和产量,可以为中国温室黄瓜生产的氮肥优化管理决策提供参考.     

Heterosis in numbers of differentiated,degenerated, and surviving spikelets and their relations to the dry matter production in F1 hybrids of rice

Heterosis in the number of differentiated, degenerated, and surviving spikelets in two important Chinese F₁ hybrids Shanyou 63 (SY63) and Yayou 2 (YY2) and their parents was observed under solution culture conditions. The results indicated that the number of differentiated, degenerated, and surviving spikelets all showed a very high value for mid-parental (MP) heterosis in the hybrids at both panicle and plant levels. The increase in the number of surviving spikelets primarily depended on that of the number of differentiated spikelets. The percentage of degenerated spikelets showed a positive value for MP and higher-parental (HP) heterosis (increase) in SY63, while it showed a negative value for MP and HP heterosis (decrease) in YY2. Morphologically, the components of the number of surviving spikelets increased in the hybrids, especially the number of surviving secondary rachis branches. Dry matter production at heading showed a high value for MP and HP heterosis. However, the ratio of dry matter weight to the number of differentiated spikelets did not show a MP heterosis. The hybrids showed a lower percentage of degenerated spikelets for the same ratio of dry matter weight to the number of differentiated spikelets. The N uptake in the hybrids showed a MP and HP heterosis, but the efficiency of the N in producing the number of surviving spikelets showed a negative value for MP and HP heterosis. The MP and HP heterosis in the sink-source ratio of the number of surviving spikelets to the leaf area varied considerably with the combinations. These findings suggested that still many characters could be further improved in F₁ hybrid rice.     

Effects of drainage intensity on water and nitrogen use efficiency and rice grain yield in a semi-arid marshland in Rwanda

ABSTRACT

Drainage management is important in intensification of irrigated paddy rice production. This study assessed the effects of drainage intensity on water and nitrogen use efficiency and rice grain yield in a field experiment conducted during three seasons in Rwanda. The experiment comprised 12 plots with four blocks and three treatments: DS_0.6 (0.6 m deep drain), DD1_1.2 (1.2 m deep drain, control structure open four times per week), and DD2_1.2 (1.2 m deep drain, control structure open two times per week). Outflow was calculated from water balance. Nitrogen (N) content in drainage water was determined weekly. Crop yield and N uptake were determined in grain and straw.

In all seasons, grain yield was 61–131% higher, crop N uptake was 24–90% higher, harvest index (HI) was 24–65% higher and water use efficiency (WUE) was 50–150% higher in treatments DD1_1.2 and DD2_1.2 than in DS_0.6. There was a decrease in soil carbon/nitrogen ratio at the end of Seasons 2 and 3. Recirculating straw to fields is thus necessary to replenish SOC for long-term soil fertility. A practical implication of the study is that managed deep drainage systems could enhance water use efficiency and rice grain yield in poorly drained paddy fields.     

Response of differentiated and degenerated spikelets to top-dressing,shading and day/night temperature treatments in rice cultivars with large panicles

The presence of large panicles enables to reach a sufficient number of surviving spikelets per unit area for further increase of rice yield. However, the response of differentiated and degenerated spikelets to environmental factors in terms of number in cultivars with large panicles has not been elucidated. By applying top-dressing at different rates and frequencies, shading, and day/night temperature treatments in pot experiments, we observed the response of the main stem in two cultivars with large panicles: Yangdao 4 (Chinese indica) and Akenohoshi (Japanese japonica-indica hybrid). The results showed that top-dressing increased the number of differentiated spikelets per panicle and decreased the percentage of degenerated spikelets. Consequently, the number of surviving spikelets per panicle increased. Shading increased the percentage of degenerated spikelets, resulting in the decrease of the number of surviving spikelets per panicle. Higher day/night temperature treatments led to a higher percentage of degenerated spikelets. The treatments affected mainly the spikelets on the secondary branches, while the number of spikelets on the primary branches did not change appreciably, irrespective of the presence of differentiated, degenerated, and surviving spikelets. The influence on the number of surviving spikelets per panicle depended on the number of differentiated spikelets. Shading effect on the percentage of degenerated spikelets also depended on the number of differentiated spikelets per panicle. The decrease of the percentage of degenerated spikelets was associated with the increase of the shoot dry weight (SDW) at heading and the ratio of SDW-differentiated spikelets. The SDW and N absorption at heading affected more significantly the number of surviving spikelets compared to the ratio of surviving spikelets-SDW and surviving spikelets-N, respectively. The above results were similar in Akenohoshi and Yangdao 4. In Akenohoshi, the percentage of degenerated spikelets responded much more conspicuously to the change of SDW or the ratio of SDW -differentiated spikelets than that in Yangdao 4. So did the number of surviving spikelets to SDW and N absorption at heading. Akenohoshi showed a higher ratio of surviving spikelets-N than Yangdao 4. These differences may account for the fact that Akenohoshi showed a larger number of surviving spikelets per panicle than Yangdao 4, even at the same levels of SDW and N absorption.     

两个水稻基因型根际磷素组分、pH以及磷酸酶活性的动态变化

A rhizobox experiment with two phosphorus （P） treatments, zero-P （0 mg P kg^-1） and plus-P （100 mg P kg^-1） as Ca（H2PO4）2.H2O, was conducted to study the chemical and biochemical properties in the rhizosphere of two rice genotypes （cv. Zhongbu 51 and Pembe） different in P uptake ability and their relationship with the depletion of soil P fractions. Plant P uptake, pH, phosphatase activity, and soil P fractions in the rhizosphere were measured. Both total dry weight and total P uptake of Pembe were significantly （P 〈 0.05） higher than those of Zhongbu 51 in the zero-P and plus-P treatments. Significant depletions of resin-Pi, NaHCO3-Pi, NaHCO3-Po, and NaOH-Pi, where Pi stands for inorganic P and Po for organic P, were observed in the rhizosphere of both Zhongbu 51 and Pembe under both P treatments. Pembe showed a greater ability than Zhongbu 51 in depleting resin-Pi, NaHCO3-Pi, NaHCO3-Po, NaOH-Pi, and NaOH- Po in the rhizosphere. HCl-Pi and residual-P were not depleted in the rhizosphere of both genotypes, regardless of P treatments despite significant acidification in the rhizosphere of Pembe under zero-P treatment. Higher acid phosphatase （AcPME） activity and alkaline phosphatase （AlPME） activity were observed in the rhizosphere of both Zhongbu 51 and Pembe compared to the corresponding controls without plant. AcPME activity was negatively （P 〈 0.01） correlated to NaHCO3-Po concentration in the rhizosphere of both Zhongbu 51 and Pembe, suggesting that AcPME was associated with the mineralization of soil organic P.     

不同时期施锌对旱稻籽粒锌积累的影响

为了探明不同时期施锌肥对旱稻籽粒锌积累的影响,在田间条件下对两个旱稻供试品种(巴西陆稻和旱稻502)进行不同时期施锌肥(100 kg/hm~2 ZnSO_4·7H_2O)处理(基施或花前7 d土壤追施),收获期对旱稻各器官锌含量进行测定和分析.结果表明,与对照(未施锌)和基施锌肥相比,花前7 d追施锌肥能显著增加地上部生物量和籽粒产量.施锌肥两处理均显著提高了旱稻地上部锌积累量.与基施锌肥相比,花前7 d施锌肥更能增加旱稻糙米中锌的含量,但在巴西陆稻上两种施锌方法对籽粒产量的增加均不显著.     

在施钾条件下灌溉水稻的养分吸收和利用效率研究

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha^-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.     

Influence of nitrogen application on dry biomass allocation and translocation in two maize varieties under short pre-anthesis and prolonged bracketing flowering periods of drought

Plants have evolved different mechanisms to survive under stress conditions. This field study was conducted to evaluate the influence of nitrogen (N) application on dry biomass allocation and translocation in two maize varieties under short pre-anthesis and prolonged bracketing flowering period of drought. Two maize varieties, ‘Pioneer 30B80? and ‘Suwan 4452? receiving N at 0 (control), 160 (optimal) and 320 (supra-optimal) kg ha^?1 were subjected to short pre-anthesis and prolonged bracketing flowering periods of drought. Prolonged bracketing flowering period of drought had more suppressive effect on anthesis-silking interval, dry matter allocation and translocation, leaf greenness, contribution of current assimilates to grain (CCAG), kernel number, kernel weight and kernel yield of two maize varieties than a short pre-anthesis drought. Nitrogen application at optimal level was the best for all traits, except CCAG. The maize variety ‘Pioneer 30B80? performed better under both drought types due to more root xylem vessels of large size and more accumulation of dry matter in leaves and roots than the variety ‘Suwan 4452?. Therefore, the variety ‘Pioneer 30B80? may be planted in drought prone environments and may be used in breeding program aimed at developing drought-tolerant cultivars.     

水稻耐盐性的机理

Shaheen Basmati was evolved as a salt tolerant fine rice variety by the Soil Salinity Research Institute,Pindi Bhattian, Pakistan. Water culture studies were conducted to investigate the physiological mechanism exercised by this variety in particular and rice plant in general to face the saline environment. Performance of this rice variety and the concentration and uptake of ions were studied under stress of three salinity levels(30, 60 and 90 mmolL^-1) created with NaC1. Recorded data indicated that shoot dry matter was not significantly affected by all the three levels of salinity. However, NaC1 levels of 60 and 90 mmol L^-1 affected the root dry matter significantly. Sodium concentration and uptake was enhanced significantly in root and shoot at the first level of salinity (30 mmol L^-1) but thereafter the differences were non-significant, indicating the preferential absorption of this cation. The K concentration decreased significantly in shoots at all the levels. The impact was less pronounced in roots as far as K absorption was concerned. The effect on Ca and Mg concentrations was not significant. The values of K:Na, Ca:Na and (Ca Mg):Na ratios in shoot and root were comparatively low under stress conditions, indicating that selective ion absorption may be the principal salt tolerance mechanism of variety Shaheen Basmati when grown in a saline medium.     

穗分化期旱涝急转对双季超级杂交稻物质积累和产量形成的影响

采用桶栽方式,以超级杂交早稻品种(淦鑫203)、超级杂交晚稻品种(五丰优T025)为材料,于穗分化初期设置不旱不涝(对照CK)、轻旱不涝(T11)、重旱不涝(T2)、不旱轻涝(T3)、不旱重涝(T4)、重旱轻涝(T5)、重旱重涝(T6)、轻旱轻涝(T7)和轻旱重涝(T8)处理,分析各处理产量及其构成因素、干物质积累与分配和净光合速率等指标。结果表明:(1)"旱"、"涝"及"旱涝急转"使超级杂交早、晚稻单株产量不同程度下降,早稻T1、T2、T3、T4、T5、T6、T7和T8单株产量分别比CK降低8.89%、21.42%、8.33%、12.04%、19.65%、31.23%、15.39%和17.29%,晚稻分别降低6.21%、15.06%、7.77%、11.53%、17.40%、20.85%、13.46%和11.70%,早、晚稻以T2和T6处理产量下降较多,尤其T6处理产量降幅最大,表明单纯前期轻旱(T1)和后期轻涝(T3)对产量的影响相对较小,而单纯前期重旱(T2)和后期重涝(T4)对产量的影响相对较大,T2比T4对产量的影响更大,且重旱重涝处理下水稻单株产量存在一定程度的叠加减产效应。产量构成上,早、晚稻产量下降的主要原因是较大幅度降低了单株有效穗数、每穗总粒数、结实率和二次枝梗数,各处理对产量构成的影响规律与单株产量大致相同。(2)早、晚稻"旱"、"涝"及"旱涝急转"等处理结束初期与CK比较,其茎、叶干物质量均不同程度下降,其中早、晚稻成熟期T6处理穗干物质量分别比CK下降33.40%、19.88%,表现为穗型变小。(3)"旱"、"涝"及"旱涝急转"使早、晚稻叶片叶绿素含量(SPAD值)降低,其中早、晚稻均以T6处理的SPAD值降幅最大,且与CK一直呈显著性差异。(4)至抽穗期,早、晚稻叶片净光合速率均以T6处理最低,分别比CK下降37.57%、10.17%。研究结果说明,生长前期重旱后期急转重涝对早、晚稻成熟期穗部干物质量及总干物质量的影响最大,重旱重涝急转表现为叠加损伤效应。