PB0喷施对矮化富士幼树成花及碳水化合物积累的影响

以‘长富2号’为试材,研究不同浓度PBO喷施处理对富士苹果幼树成花、新梢生长、叶片和芽碳水化合物含量变化的影响。结果表明:(1)PBO喷施处理能在一定程度上提高‘长富2号’幼树上中下部位枝条的成花率和对树体各个部位枝条新梢生长形成抑制。不同浓度PBO喷施处理对‘长富2号’幼树叶片和芽碳水化合物含量变化的影响有所差异,对于高浓度PBO喷施处理(4000 mg·L^-1和6667 mg·L^-1),幼树各部位叶片蔗糖、葡萄糖、山梨醇和可溶性总糖含量在幼树生长前期(5-7月)增加显著,而淀粉含量在此时期却显著地减小;同样,高浓度PBO喷施处理对幼树芽山梨醇和可溶性总糖含量的增加作用在6月份均达显著水平,却导致芽淀粉含量在7月份显著地减小。(2)叶片与芽之间的碳水化合物的转化或转移和花芽的形成有密切的关系;高浓度PBO喷施处理(6667 mg·L^-1),叶片山梨醇和可溶性总糖含量与芽相应指标之间具有显著的正相关,而两者淀粉含量之间的相关性却不显著。考虑到成本等因素,建议在花芽分化的关键时期(5-7月),喷施4 000 mg· L^-1 PBO可以有效促进‘长富2号’幼树花芽的形成。     

The Control of Phytophthora cinnamomi Rands in a South African Forest Nursery

Tests of several fumigants which control Phytophthora cinnamomi Rands under field and glasshouse conditions are reported. The soil fumigant basamid is the cheapest effective treatment available, at present. The implications of failure to control Phytophthora cinnamomi for forestry, agriculture and the indigenous flora are briefly discussed.     

粉状富淀粉传统保健食材碳水化合物体外消化特性

探讨焙烤后打粉冲糊方法对富淀粉保健食材碳水化合物消化特性的影响。采用体外模拟消化方法测定各样品快消化淀粉、慢消化淀粉和抗性淀粉的含量及水解率,并对淀粉糊化温度、糊化度等进行研究。试验结果表明：冲糊水量和温度显著影响样品的水解速率和淀粉类型,增加沸水量可使所有样品的水解指数超过蒸煮处理水平,蒸煮处理山药干、芡实、莲子、薏米和红小豆血糖负荷评估值分别为47．38、42．28、29．05、42．79和28．96;沸水量大冲糊方法的血糖负荷评估值分别为51．80、55．49、50．19、50．93和40．26。控制冲糊方法或可有效控制粉状淀粉食材的消化速度和淀粉类型比例,为不同生理状况的人群控制其血糖反应提供可能性。     

意大利蝗越冬卵抗寒物质分析

意大利蝗Calliptamus italicus是新疆草原主要优势危害种,以滞育卵越冬.为弄清意大利蝗越冬卵发育及滞育过程的抗寒机制,本研究检测了自然条件下越冬卵的糖类、多元醇、脂肪和氨基酸等主要抗寒物质的含量变化,分析蝗卵发育过程不同阶段抗寒物质含量的变化趋势.结果表明,意大利蝗卵在越冬过程中,除脂肪含量无显著差异外...     

Available carbohydrates of cereal grains as affected by storage and insect infestation

Total soluble sugar, reducing sugar, non-reducing sugar and starch contents of wheat, maize and sorghum grains were affected adversely at 25, 50 and 75% insect infestation caused byTrogoderma granarium Everts andRhizopertha dominica Fabricius, separately and mixed population.R. dominica caused significant (P<0.05) reduction in available carbohydrates at 50 and 75% infestation levels whereasT. granarium achieved similar effect at 75%. Mixture of both insect species caused intermediate losses. Storage of cereal grains up to 4 months resulted in substantial increase in sugars and decrease in starch content, but storage for a shorter period of time did not cause any significant changes in levels of carbohydrates.     

低镁胁迫对马铃薯试管苗碳水化合物积累和分配的影响

以马铃薯品种"大西洋"的试管苗为材料,在5个不同镁浓度(0、188、375、750、1 500μmol·L~(-1))的MS培养基上培养,20 d后测定生理和形态指标,研究了低镁胁迫对马铃薯试管苗叶绿素含量和碳水化合物积累与分配以及根系形态建成的影响。结果表明:试管苗的总叶绿素、叶绿素a(Chla)和叶绿素b(Chlb)含量以及根冠比、总根长、根表面积、根体积和侧根数均为缺镁(0μmol·L~(-1))处理最低,分别比对照(1 500μmol·L~(-1))降低42.3%、40.8%和46.2%以及96.4%、63.9%、54.1%、82.4%和89.9%;平均根直径和Chla/Chlb值为缺镁处理最高,分别较对照增加16.7%和9%;茎叶中淀粉、蔗糖、果糖和可溶性糖含量以及根中蔗糖、果糖和可溶性糖含量均为缺镁处理最高,分别比对照增加了58.5%、54.8%、59.7%和25.9%以及22%、46.7%和54.7%,而根中淀粉含量为缺镁处理最低,较对照降低32.8%。相关性分析表明,马铃薯试管苗茎叶中淀粉、果糖和可溶性糖含量与镁浓度均呈显著负相关。说明缺镁影响马铃薯试管苗的光合作用和碳水化合物代谢,大量碳水化合物在茎叶中积累,向根部的运输量减少,侧根形成减少,根冠比降低,抑制根系的形态建成。低镁水平下(750μmol·L~(-1))试管苗的叶绿素含量增加,更多的碳水化合物向根部运输,根冠比增大,促进根系的形态建成,与正常镁水平(1 500μmol·L~(-1))下马铃薯试管苗指标变化相同,差异不显著,表明含750μmol·L~(-1)Mg~(2+)的MS培养基适宜于马铃薯试管苗的生长和发育。     

藏东南色季拉山急尖长苞冷杉非结构性碳水化合物时空动态特征

目的 为了验证高山林线的形成机理,探究树木分布上限的限制因素。 方法 本研究以色季拉山急尖长苞冷杉为研究对象,在其低海拔针阔叶混交林（3 500 m）、中海拔适生区（3 900 m）和高海拔林线过渡带（4 300 m）,分别于生长季（7月初）与非生长季（11月底）测定树木叶、枝、干和根的非结构性碳水化合物（NSC）及其组分含量,以及C、N、P含量。 结果 不同生长季节急尖长苞冷杉非结构性碳水化合物源与汇含量比较稳定,未出现碳供应不足现象;海拔对急尖长苞冷杉非结构性碳水化合物及其组分影响较小;器官间NSC含量差异显著,叶、枝、干和根在不同生长季节所侧重的生理活动和功能不同;非生长季急尖长苞冷杉非结构性碳水化合物及其组分显著高于生长季,非生长季较高的可溶性糖和NSC含量有利于抵御低温等恶劣环境;急尖长苞冷杉的NSC含量随海拔的上升呈现出递增的趋势,一定程度上支持了“生长抑制”假说。 结论 色季拉山急尖长苞冷杉的生长更多的受到了植物养分的限制,而非碳限制。     

Differences in Wheat Cultivar Response to Nitrogen Supply. II: Differences in N-Metabolism-Related Traits

Two-year field trials with winter wheat cultivars Batis and Toronto were conducted in Southern Bavaria, Germany, to investigate the possible causes of cultivar differences in response to N supply varying in total amount and time of application. The results revealed cultivar-related differences in response to N fertilization in all parameters included in this study. Amount and timing of N fertilization was a strong indicator of N uptake into canopies and three phases of cultivar differentiation became apparent. Cultivar differences in N content were most clearly expressed during early growth stages, but distinctive differences in canopy N uptake were observed during later growth stages. Nitrate reductase activity, water-soluble carbohydrates (WSC), and plant nitrate content varied in response to N supply within cultivar-specific patterns that included reversals in cultivar ranking during canopy development, and provided additional indications for elevated intensity of N metabolism in cv. Toronto when compared with cv. Batis. Apart from such differences Batis partially compensated for delayed N uptake in earlier phases during the latter part of grain filling, presumably due to differences in root system development. Cultivar differences in regression of tillering, stand density, grains per ear and grain density (grains m⁻²) on a number of N metabolism-related parameters have been determined. They contribute considerably to the understanding of cultivar differences in grain yield components, as presented in an earlier communication. For 1000 grain weight, least affected from N supply within each year, large differences between years seemed to relate to differences in WSC content observed between heading and flowering, whereas cultivar differences in the level of grain N content and reaction to N supply were more directly determined by differences in N uptake and remobilization, and possibly enhanced by sink limitations of Toronto in grain size development.     

Carbohydrates molecular structure profiles in relation to nutritional characteristics of newly developed low and normal tannin faba bean varieties in dairy cows analysed by using standard methods and the vibrational molecular spectroscopy (Ft/IR-ATR)

To our knowledge, there was no study on interactive relationship between CHO molecular structure spectral profiles of newly developed cool-season adapted faba bean and nutritional characteristics in ruminants. The aim of this study was to evaluate the impact of genotypes and tannin levels on the physicochemical and nutritional characteristics of faba bean as an alternative protein and energy source for ruminants and its relation to CHO molecular structure spectral profiles using vibrational molecular spectroscopy (Ft/IR-ATR). Eight genotypes with two tannin levels (low and normal) grown at three different locations in Saskatchewan (CDC crop research fields) were analysed. Chemical analyses were performed using AOAC standards and energy was evaluated using NRC standards. Rumen degradation kinetics were determined using in situ dairy trial. Intestinal digestion was analysed by a modified three-step in vitro technique with 12 h pre-rumen incubation in dairy cows. Molecular spectral study was performed using Ft/IR–ATR, and the molecular structural features were analysed at ca. 4000–800 cm⁻¹ using the Spectra ManagerII. CHO-related functional groups were analysed with OMNIC 7.3. The results showed low-tannin faba bean (LT) presented a highly significant difference (p < 0.05) on rumen bypass starch (BSt) compared to normal tannin faba bean (NT). On the other hand, NT had more total tract digested starch (TDST) compared to LT. No significant differences (p > 0.10) were observed for total digestible nutrients (TDN_1x), metabolizable protein (MP), feed milk value (FMV) or rumen undegraded crude protein (RUP). Results showed differences in physicochemical characteristics among faba bean varieties; however, the predicted production performance was not different within faba bean genotypes. These outcomes suggest that faba bean can be used as nutritive ingredient for dairy cattle without a significant genotype or tannin level effect on metabolic characteristics. Results from vibrational spectroscopic study showed a higher ATR-Ft/IR absorbance (p < 0.05) in NT on inherent structural CHO (STCHO), total CHO (TCHO) area and peaks (H_1015, H_1076, H_1145), and cellulosic compounds (CEC) to total CHO (TCHO) ratio. Significant correlations could be found between CHO spectral profiles and metabolic characteristics of faba bean, which indicates that structural spectral features of faba bean could be used to predict metabolic characteristics in ruminants.