铁皮石斛在人工光型密闭式植物工厂的适宜光照强度

人工光型密闭式植物工厂适于高附加值植物尤其是珍贵药用植物的大规模/低成本化生产,其环境调控对珍贵药用植物的产量和质量有重要影响。笔者研究探索在控制温度、湿度、CO2浓度和光周期的条件下,光照强度对铁皮石斛(Dendrobium officinale)组培苗生长发育的影响,以期找到铁皮石斛组培阶段在人工光可控环境下的适宜光照环境。鲜重约300mg的铁皮石斛单腋芽作为外植体在温度24±1℃、湿度65±5%、光周期12h/d、及光期CO2浓度800±50μmol/mol的环境条件下,设置光照强度为37、68、92、120μmol/(m2·s)的4组试验区,并使用容积为380mL的方型聚碳酸酯组培容器在人工光型密闭式植物工厂中培育92d。组培容器的顶部留2个直径为10mm的圆孔覆盖高分子透气膜用来与容器外进行气体交换。铁皮石斛组培苗的生长发育和生理活性在光照强度为68μmol/(m2·s)时最佳,超过92μmol/(m2·s)时呈现明显的光抑制;多糖含量随着光照强度的增强而增加,超过92μmol/(m2·s)时呈下降趋势,但是68和92μmol/(m2·s)光照强度试验区的多糖含量没有显著性差异。因此,铁皮石斛组培苗在人工光型密闭式植物工厂内培育的适宜光照强度为60￣70μmol/(m2·s)。     

Predicting effects of drainage water management in Iowa's subsurface drained landscapes

Long-term hydrologic simulations are presented predicting the effects of drainage water management on subsurface drainage, surface runoff and crop production in Iowa's subsurface drained landscapes. The deterministic hydrologic model, DRAINMOD was used to simulate Webster (fine-loamy, mixed, superactive, mesic) soil in a Continuous Corn rotation (WEBS_CC) with different drain depths from 0.75 to 1.20 m and drain spacing from 10 to 50 m in a combination of free and controlled drainage over a weather record of 60 (1945-2004) years. Shallow drainage is defined as drains installed at a drain depth of 0.75 m, and controlled drainage with a drain depth of 1.20 m restricts flow at the drain outlet to maintain a water table at 0.60 m below surface level during the winter (November-March) and summer (June-August) months. These drainage design and management modifications were evaluated against conventional drainage system installed at a drain depth of 1.20 m with free drainage at the drain outlet. The simulation results indicate the potential of a tradeoff between subsurface drainage and surface runoff as a pathway to remove excess water from the system. While a reduction of subsurface drainage may occur through the use of shallow and controlled drainage, these practices may increase surface runoff in Iowa's subsurface drained landscapes. The simulations also indicate that shallow and controlled drainage might increase the excess water stress on crop production, and thereby result in slightly lower relative yields. Field experiments are needed to examine the pathways of water movement, total water balance, and crop production under shallow and controlled drainage in Iowa's subsurface drained landscapes.     

飞机防治美国白蛾林间持续药效调查

对飞机喷洒灭幼脲3号悬浮剂防治第1代美国白蛾以及对第2代幼虫的持续控制效果的调查结果表明，在对第1代美国白蛾1～3龄幼虫喷药后，两代幼虫取食后8天的防效均达100％，而且与人工喷药防治相比具有成本低、效益高的优点。     

Towards flexible management of postharvest variation in fruit firmness of three apple cultivars

Stochastic modeling provides a useful tool in managing biological variation in the postharvest chain. In the current study, the fruit-to-fruit variability in the postharvest firmness of apples was modeled. Apples from three cultivars (‘Jonagold’, ‘Braeburn’, and ‘Kanzi’) were harvested at different levels of maturity, and stored at different temperatures and controlled atmosphere (CA) conditions. By using a kinetic model describing firmness breakdown as a function of time, temperature, controlled atmosphere conditions and endogenous ethylene concentration, the main stochastic variables were identified as the initial firmness and the rate constants for firmness breakdown and ethylene production. Treating these variables as random model parameters, the Monte Carlo method was used to simulate the propagation of the fruit-to-fruit variability in flesh firmness within a batch of apples during storage under different CA conditions and subsequent shelf-life exposure. The model was validated using independent data sets from apples picked in a different season. The model developed in this study can be used to predict the probability of having apples of certain firmness after long term storage for different scenarios of temperatures and CA conditions.     

针叶小爪螨对樟子松的危害及防治试验

首次在陕西榆林发现针叶小爪螨危害樟子松。经用７种化学药剂野外防治试验，其中三氯杀螨醇，克螨特，双甲脒施药３天后虫口减退均达８５％以上。     

Growth and nutritional responses of bareroot Jeffrey pine on a Sierra Nevada surface mine to minisite applications of fertilizer and lime

The effects of two controlled release fertilizers, Forestcote 22-4-6 + Minors and Dry Site 21-6-2 + Minors, and also dolomitic lime, on growth and nutrition of bareroot Jeffrey pine (Pinus jeffreyi Grev. & Balf.) were investigated. Forestcote, which consists of loose prills, and Dry Site, consisting of prepackaged prills, were administered with two rates, while a single liming rate was used. An acidic Sierra Nevada surface mine provided the study site, and all amendments were applied at outplanting to the backfill of augered planting holes. Without impacting survival, both fertilizer formulations enhanced seedling growth, particularly at a 16 g rather than an 8 g application rate, although Forestcote was marginally more effective in this regard. In contrast, liming at a 27 g rate induced severe mortality and offset much of the growth gains resulting from fertilization. Improvements in N and P nutrition, as revealed by foliar analysis, probably accounted for much of the growth stimulation exhibited by fertilized seedlings, but reductions in the uptake of potentially phytotoxic trace elements such as Mn and Al and increases in base cation/metallic element ratios likely also contributed. The high application rate was generally preeminent in eliciting these nutritional responses. Liming induced little alteration of seedling nutrition. Impaired water relations may have caused the unfavorable responses to this treatment.     

南水北调东线徐州段水环境现状及其污染防治对策

对南水北调东线徐州段7个控制断面2004年水质监测结果进行评价分析,结果表明,水质达标率仅为42.9%,水体污染以耗氧性污染物和氨氮为特征的有机污染为主。结合当地实际,分析了南水北调东线徐州段水质超标的原因,并根据当地经济、自然特征,提出了针对性较强、切实可行的水污染防治对策和措施。     

缓控释肥组配对长江上游早熟杂交籼稻再生稻产量和物质积累的影响

旨在研究长江上游再生稻区头季稻缓控释肥优化方案对早熟杂交籼稻头季稻和再生稻物质积累及产量的调控效应。以早熟杂交籼稻‘广8优粤禾丝苗’为材料,头季稻机插开展试验,设置6个施肥处理,分别为4个月树脂包膜尿素一次性基施处理(B-PCU)、缓释掺混肥一次性基施处理(B-SRFB)、4个月树脂包膜尿素一基一蘖处理(BT-PCU)、缓释掺混肥一基一蘖处理(BT-SRFB)、当地常规施氮处理(CF)和全生育期不施氮肥对照处理(CK)。结果表明,较CF处理,4个月树脂包膜尿素头季稻产量降低,再生稻产量增加,差异不显著;缓释掺混肥增加头季稻和再生稻产量,再生季产量差异达显著水平,主要归因于有效穗明显增加,提高库容水平,一基一蘖处理一次性基施处理。较CF处理,不同缓控释肥处理均降低头季稻花前的物质积累,但不同缓控释肥一基一蘖处理明显增加成熟期物质积累,归因于花后作物生长速率显著增加;再生季,不同施肥处理再生力相当,缓释掺混肥处理叶面积指数显著高于CF和4个月树脂尿素,再生季作物生长速率明显增加,进而提高成熟期物质积累,其中,缓释掺混肥一基一蘖处理最高。说明长江上游早熟杂交籼稻‘广8优粤禾丝苗’在中稻-再生稻种植模式中,头季稻采用缓释掺混肥组配尿素的施肥方式有利于中稻-再生稻群体光合产物积累和产量增加。     

杉木不同造林方式效益分析

从福建省洋口国有林场引进杉木2代苗木,通过炼山和不炼山2种方式在福建省沙县设立造林对比试验。结果显示：杉木不炼山方式造林比炼山方式造林投资高12.6%;杉木炼山方式造林前期生长比不炼山方式造林快,5a后渐渐持平,8a后不炼山方式造林显著优于炼山造林;炼山造林还导致土壤容重增大,土壤孔隙度降低,土壤变得紧实。     

不同冰温温度对山楂果实生理及品质的影响

为延长山楂果实的保鲜期,提高果实贮藏品质,筛选适宜山楂果实冰温温度参数。在以普通冷藏(0±0.5)℃,以及果实温度为-0.4、-1.0、-1.6℃的4个不同温度的贮藏条件下,对贮藏期间‘敞口’山楂果实采后生理及品质变化进行研究。结果表明,-1.0℃的冰温处理降低了山楂果实的乙烯生成速率和最大生成量,减缓了果肉硬度、可滴定酸(TA)和维生素C(Vc)含量的下降,有效抑制了果肉中丙二醛(MDA)的积累,减轻了贮藏后期多酚氧化酶(PPO)活性的上升和酚类物质含量的减少,进而延缓了山楂果实的生理衰老进程,维持了山楂果实的良好贮藏品质;而在贮藏160天后,-1.6℃的冰温处理的山楂果实乙烯释放峰值显著增高,TA和Vc降解迅速,MDA含量显著上升,PPO活性明显上升和酚类物质含量迅速减少,加速了果实的褐变速率,生理伤害症状明显,品质劣变严重。综上所述,在-1.0℃的冰温条件下,山楂果实生理代谢被有效抑制且未出现生理伤害,贮藏效果最佳。