粮饲兼用型玉米青贮产量形成与生理特性的研究

本试验选用在四川当地适合作青贮的粮饲兼用型玉米品种川单21、成单22、雅玉8号和燎原青贮玉米2号及从新疆引进的专用青贮玉米品种新青2号为材料，研究了不同青贮玉米的产量形成及其光合生理特性。结果表明，鲜物质、干物质产量以及果穗产量均以粮饲兼用型玉米较高，其中以雅王8号表现最优。粮饲兼用型品种在抽丝后的叶面积指数(LAI)、群体光合势(LAD)和净光合率(NAR)等几个重要生理指标上均表现出明显优势，叶面积指数、群体光合势持续期长、净光合速率高而衰减速率慢是粮饲兼用型品种产量高的重要生理原因。     

Effects of diurnal temperature alternations and light quality on growth,morphogenesis and carbohydrate content of Cucumis sativus L.

The effects of the difference (DIF) between day/night temperature (DT/NT) and end-of-day (EOD) light quality on growth, morphology, dry matter (DM) content and carbohydrate status in cucumber (Cucumis sativus L.) were examined. Plants were grown under a 12 h high light intensity period and DT/NT of 25/19 °C (positive DIF) or 19/25 °C (negative DIF) in combination with an exposure of 30 min EOD-red (EOD-R) or far-red (EOD-FR) light. A significant interaction between DIF and EOD light quality was found on morphology, DM and carbohydrate content in axial plant organs like stems and petioles, but not in leaf blades and roots. Positive DIF induced taller stems, and higher DM and carbohydrate content than negative DIF when the plants were grown under EOD-R. The stems developed under EOD-FR were tall and accumulated the highest content of DM and carbohydrates and only small differences were found between positive DIF and negative DIF. Under EOD-R a higher content of glucose and fructose was found under positive than negative DIF, while EOD-FR light resulted in a high glucose and fructose content under both positive and negative DIF and thereby equalized the effect of the two temperature treatments. The results show that positive DIF can induce similar responses in elongation growth, DM and carbohydrate accumulation as EOD-FR, and further that phytochrome status interact with the responses to alternating DT and NT.     

Growth and yield response of common buckwheat (Fagopyrum esculentum Moench) to waterlogging at different vegetative stages

ABSTRACT

This study identified timing (1st, 3rd, or 5th leaf stage) and duration (1, 3, 6, or 10 days) of waterlogging treatment during the vegetative stage that had the most severe effect on yield and elucidated yield determining process. Yield was reduced the most by the waterlogging treatments at the 3rd leaf stage. Among stages, yield was significantly depressed, when the treatment duration was longer than 6 days. Seed weight of the 1st branches declined more under waterlogging treatments than did that of main stem and 2nd branches, accounting for approximately 55% of total seed weight in all treatments. On the other hand, the decline in node and branch numbers was more pronounced for 2nd branches than 1st branches at the ripening stage. The development of the 2nd branches during ripening did not contribute much to increase sink capacity. Development of the main stem and the 1st branches was almost complete until the full flowering stage and shoot dry weight did not increase from the full flowering stage to the ripening stage. Shoot dry weight at the full flowering stage was determined by both leaf number and net assimilation rate (NAR). Flower cluster number at that stage was significantly correlated with total seed weight. These results showed that the critical timing was at the 3rd leaf stage and the critical duration was longer than 6 days and indicated that maintenance of leaf number and NAR and development of flowers on the 1st branches until the full flowering stage would ensure the yield.

Abbreviations: NAR - net assimilation rate, SLA - specific leaf area, g_s - stomatal conductance.     

两个超级杂交水稻品种物质生产的特性

定量分析超级杂交水稻若干群体指标的动态特征,以期为其高产栽培提供依据。于2011年和2012年在大田条件下,以超级杂交水稻准两优527、Q优6号和对照品种II优838为试材,通过连续测定干物质和叶面积,建立了水稻群体干物质和相对叶面积指数动态模型,进而以群体干物质和相对叶面积指数模型为基础,分析了超级杂交水稻作物生长率、相对生长率、光合势、净同化率、叶面积比率动态变化特征。结果表明,超级杂交水稻快增期的干物质积累量及其占总生物量的比例均高于对照。作物生长率(CGR)随移栽后时间呈先升高后下降的单峰曲线变化,其快增期的CGR较大。与对照相比,超级杂交水稻相对生长率(RGR)表现出上升快、峰值大、下降快的特点。准两优527在移栽后23 d至成熟期高于对照,Q优6号的RGR在移栽后43 d以前低于对照,移栽后43 d至113 d高于对照,两者在移栽后113 d至成熟期的RGR相差不大。不同水稻净同化率(NAR)随移栽后时间呈先上升后下降的单峰曲线变化,最大NAR出现在移栽后43~53 d。总光合势与快增期光合势及与快增期绿叶面积持续时间均呈极显著正相关。2个超级杂交水稻叶面积比率(LAR)在移栽后23 d至43 d迅速下降,移栽后43 d至73 d缓慢下降,移栽后73 d至成熟期快速下降,其快增期的LAR较大。     

窄畦窄行穴播大豆群体生理指标及光分布特点

采用大区对比法对窄畦窄行穴播大豆各生育阶段群体生理指标及冠层光分布特点进行了分析。结果表明：与传统的宽畦宽行穴播相比,窄畦窄行穴播大豆群体ＬＡＩ高,叶片功能期长,相对光强高;在鼓粒期（Ｒ５）,降低了叶片密集点所处的高度,减小了叶片密集度和消光系数,改善了整个冠层的光照条件,提高了净光合生产率,积累了更多的干物质,从而使籽粒产量提高了１７．８％。     

Effect of Shading on the Growth and Yield of Mungbean (Vigna radiata [L.] Wilczek)

Mungbean grown as intercrop suffers shading stress form companion crop at different growth stages. Grain filling stage, which appears to be very much sensitive to light conditions, needs special attention to deal with, in order to maximize the benefit from intercropping systems. Growth and yield response of mungbean to different shading conditions imposed at the onset of pod formation stage was evaluated. Shading nets were used to cut down the incident photosynthetic active rediation by 15 %, 45 % and 75 %. There was almost no difference between the control and 15 % shaded plants for all the parameters studied. Total dry weight was found to decrease with increase in shading intensity and this phenomenon continued till the maturity of the crop. The crop growth rate, relative growth rate and net assimilation rate decreased due to shading. Lower specific leaf weight and higher chlorophyll content were due to increased shading. Decreased photosynthetic active radiation caused significant reduction in pods per plant and thus there was a significant decrease in seed yield per plant. In order to avoid yield loss due to shading at grain filling stage, agronomic manipulation and selection of suitable genotypes are necessary.     

Effects of plant density in broccoli on yield and radiation use efficiency

The effects of plant density on broccoli (Brassica oleracea L. var. italica Plenck) commercial characteristics are well determined. However, it is not completely clear how the broccoli plant respond to changes in plant shading as a result of different plant densities. The objective of this experiment was to determine the effect of plant density on intercepted photosynthetically active radiation (PAR), plant architecture, and plant growth and production. “Legacy” broccoli plants were grown in pots in a greenhouse in the seasons of 2002 and 2003 at 2, 4, 6 or 8 plants m⁻² (temperatures: between 10.0 and 16.1 °C, average incident PAR: 12 mol m⁻² day⁻¹). Plant density affected the intercepted and accumulated PAR. There were not effects on the length of the vegetative and reproductive periods, the total and final number of leaves, and the spear diameter and fresh weight. The magnitude and evolution of leaf area (LA) was independent of plant density up to 70 days after transplant (dat). Since then on, LA increased linearly with plant density. The highest intercepted PAR was 70–72% with 6–8 plants m⁻². With the increase in plant density: the erectness of the upper leaves and stem length increased, the extinction coefficient decreased and commercial spear (inflorescence plus a portion of stem 10 cm long) weight decreased (but it was due to the stem portion of the spear and not to the edible portion). On an area basis, the decrease in commercial spear weight with plant density was more than compensated by the higher number of plants. The radiation use efficiency (RUE) increased proportionally with the leaf area index (LAI) up to a LAI of about 3, and then stabilized. The only effect of plant density on dry weight partitioning was to decrease the dry weight allocated to the stem portion of the spear. As plant density increased, and consequently the degree of shading increased, the net assimilation rate (NAR) decreased and the leaf area ratio (LAR) increased. This compensatory change between NAR and LAR, kept the relative growth rate (RGR) for individual plants almost constant.     

Modulation in growth,development, and yield of Camelina sativa by nitrogen application under water stress conditions

Camelina sativa has rejuvenated as a successful oilseed crop in the recent years. It is a low-input-requiring crop with an unusual fatty acid composition. A pot experiment was conducted in rain-out shelter to investigate the effect of different nitrogen levels (N₀ = 0, N₁ = 50, N₂ = 100, and N₃ = 150 kg ha^?1) on the growth and yield of two C. sativa genotypes (Australian and Canadian) under normal [100% field capacity (FC)] and water stressed (60% FC) conditions. The experiment was laid out in a completely randomized design with factorial arrangement having three replicates in the Department of Crop Physiology, University of Agriculture, Faisalabad. The results indicated that nitrogen doses and water stress levels significantly affected the growth and yield of C. sativa. Maximum values for growth indices like leaf area index (LAI), crop growth rate (CGR), leaf area duration (LAD), net assimilation rate (NAR), and yield attributes were observed under N₂ treatment (100 kg ha^?1) followed by the treatment in which nitrogen was applied at the rate of 50 kg ha^?1. However, growth and yield components significantly reduced under water stress conditions (60% FC). Of both the genotypes, Australian Camelina performed better as compared to Canadian Camelina under both non-stress and drought stress conditions.     

北疆春大豆生长动态及干物质积累与分配

通过对春大豆整个生育期内几个重要的生理指标的动态变化规律的研究表明,就不同品种而言,各个生理指标的峰值虽略有差异,但仍是有规律可循的,株高、LAR、NAR、叶绿素含量、叶面积指数分别主要出现在结荚期(或鼓粒期)、始花期、鼓粒盛期、鼓粒期和鼓粒盛期;这些峰值可与产量相结合用于品种选育.在物质积累与分配上,结荚至鼓粒盛期最多,而分配则是从结荚期开始,分配到荚中的干物质所占的比重逐渐升高,反映了物质分配重心的转移过程.     

NAR神经网络的应用与检验——以城市居民生活需水定额为例

NAR神经网络具有反馈和记忆功能,其在时间序列的建模仿真方面具有显著优点。以城市居民生活需水定额为例,采用NAR神经网络建立了贵州省城市居民生活需水定额的时间序列模型,通过试验法、留一法交叉检验讨论了模型相关输入参数的计算与选取,通过相关系数、Nash效率系数、LBQ检验、ROC曲线方法检验了模型的性能和预测结果的精度,进而对贵州省城市居民生活需水定额变化趋势进行了预测。结果表明,(1)NAR模型性能良好并具有较高的预测精度,NAR神经网络的相关系数r、Nash效率系数分别达到0.97、0.87,LBQ检验得出预测结果误差不存在自相关性,采用预测结果绘制ROC曲线,其AUC值达到0.938(处于水平1,有较高准确性);(2)需水定额合理性评价中,预测2020年、2030年需水定额分别为137.72 L/(人·d)、132.94 L/(人·d),满足《室外给水设计规范》(GB50013—2006)的要求,具有较好的适用性。