Dietary potassium requirement of juvenile grass carp (Ctenopharyngodon idella Val.) based on growth and tissue potassium content

A growth trial was conducted to estimate the optimum concentration of dietary potassium (K) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (3.96 ± 0.06 g) were fed diets containing graded levels (0.87, 2.90, 5.37, 7.54, 9.87 and 12.4 g kg^?1) of K for 8 weeks. Final body weight, weight gain and feed efficiency and gill Na⁺‐K⁺ ATPase activity were highest in fish fed with 9.87 g kg^?1 dietary K and lowest in fish fed the basal diet (P < 0.05). The K contents in whole body and muscle were linearly increased up to the 9.87 g kg^?1 dietary K and then levelled off beyond this level, whereas in scales and vertebrae up to the 7.54 g kg^?1 dietary K (P < 0.05). However, dietary K levels had no significant effect on ash, Ca, P and Mg contents in whole body, scales, vertebrae or muscle. Analysis using polynomial regression of weight gain and gill Na⁺‐K⁺ ATPase activity and using the broken‐line regression of whole body K concentrations indicated that the adequate dietary K concentration for grass carp is about 9.45–9.99 g kg^?1 diet.     

乙烯利催熟番茄应用现状及对品质的影响

系统分析了山东省8个地市番茄生产中利用乙烯利催熟现状,针对番茄生产中使用乙烯利存在的问题,设计乙烯利对番茄不同的处理方式和处理剂量,探讨乙烯利不同使用方式对番茄成熟和品质的影响。结果表明:涂抹花梗处理方式对番茄成熟品相和品质的影响最小,正常使用剂量情况下Vc含量降低4.35~5.89%,番茄红素含量降低8.77~9.78%,可溶性固形物含量降低2.45~3.17%;随着使用剂量的提高,对番茄成熟品相和品质的影响加大。     

甘蔗品种的AFLP和SSR标记鉴定及其应用

品种遗传多样性和指纹图谱是育种、品种权保护和新品种推广等工作的重要参考和依据。本研究选用38个来自国家甘蔗品种区域试验的甘蔗新品种(系), 以9对AFLP标记扩增出348个位点, 多态性位点248个, 多态性比率为72.26%; 15对SSR标记扩增出180个位点, 多态性位点176个, 多态性比率为97.78%。38个新品种(系)的遗传相似系数分布在0.668~0.847之间, 其箱线图分布特征显示, 其中的FN、MT、YZ、YG、GT等系列品种(系)遗传基础相似。通过UPGMA聚类表明, 可在遗传相似系数为0.732处将38个甘蔗新品种(系)划分为2个群体, 其中福农09-2201和桂糖06-1492作为一个子群体最先被划分出来, 它们在群体中的异质性较强; 另外, 在遗传相似性系数为0.770处划分出一个子群体a, 其中包含参照品种ROC22、福农07-3206、福农40、海蔗22、桂糖09-12、柳城07-150等品种(系)。ROC22具有广适应性和高产高糖等优良特性, 子群体a中的另外几个品种(系)则更有可能拥有这些特性, 具有更高的推广潜力。本研究选择60个SSR位点构建了38个甘蔗新品种(系)的指纹图谱, 对品种鉴定及品种权的保护具有重要作用, 可望直接应用于指导甘蔗种质资源的遗传多样性评价和分子指纹图谱鉴定, 并将为这些品种(系)推广布局或作为杂交亲本利用提供参考和借鉴。     

柳州甘蔗生育北界气候过渡带大规模种植的气候风险与应对策略

通过分析位于柳州甘蔗生育北界气候过渡带的融安县气候资源对甘蔗生长发育的利弊条件以及霜冻、干旱、洪涝灾害的气候风险,提出融安县大规模发展甘蔗生产的气候应对策略,从而论证了：只要合理利用山区特殊的气候资源,通过物力、人力做到趋利避害,位于甘蔗生育北界气候过渡带的融安县完全具备大规模发展甘蔗种植的气候可行性。     

Potassium and Silicon Improve Yield and Juice Quality in Sugarcane (Saccharum officinarum L.) under Salt Stress

Soil salinity is a major abiotic stress which adversely affects the yield and juice quality in sugarcane. However, the mineral nutrient status of plant plays a crucial role in increasing plant tolerance to salinity. We investigated the effects of K and/or Si on plant growth, yield and juice quality in two sugarcane genotypes differing in salinity tolerance. Addition of K and Si significantly (P ≤ 0.05) increased K and Si concentrations and decreased the accumulation of Na⁺ in plants under salt stress. Cane yield and yield attributes were significantly (P ≤ 0.05) higher where K and Si were added. Juice quality characteristics like Brix (% soluble solids in juice), Pol (% sucrose in juice), commercial cane sugar (CCS) and sugar recovery in both sugarcane genotypes were also significantly (P ≤ 0.05) improved with the supplementation of K and Si. For most of the growth parameters, it was found that K either alone or in combination with Si was more effective to alleviate salt stress in both sugarcane genotypes than Si alone. Moreover, the beneficial effects of K and Si were more pronounced in salt sensitive genotype than in salt tolerant genotype. The results suggested that K and Si counteracted the deleterious effects of high salinity/sodicity in sugarcane by lowering the accumulation of Na⁺ and increase in K⁺ concentration with a resultant improvement in K⁺/Na⁺ ratio which is a good indicator to assess plant tolerance to salinity.     

甘蔗低温灾害减灾技术措施

2008年1月12日至2月20日广西出现近50年没有的、持续低温雨雪冰冻灾害天气,给广西的甘蔗生产带来了不利影响。文章结合不同阶段甘蔗受灾情况调查分析,指出甘蔗低温灾害类型以及不同类型灾害对甘蔗生产的影响,并针对不同的受灾情况提出了相应的减灾措施与建议,以利及时进行甘蔗受害评估和指导蔗农生产。     

不同春大豆品种与甘蔗间种的产量结果分析

2007年春季在广西武鸣县两江镇进行不同春大豆品种与甘蔗间种对比试验。结果表明,在参试的6个春大豆品种中,以桂816的综合表现最好、产量最高,单产达1267．5kg／hm^2,比对照增产378．0kg／hm^2,增产42．5％,增产达显著水平;其次是桂春1号和桂春2号,分别比对照增产220．5、120．0kg／hm^2,这3个春大豆品种均适合与甘蔗进行间种。     

长期施用含氯化肥对甘蔗和土壤氯积累的影响

在甘蔗上连续四年施用含氯化肥的长期定位试验,结果表明:在等氮、磷、钾养分条件下,含氯化肥的施用对甘蔗的蔗茎产量和蔗糖产量未产生显著不良影响;蔗叶和蔗汁的氯含量随施氯量的增加而增加,但施氯量对蔗叶和蔗汁中氮、磷、钾含量无不良影响;在第四年,施氯量最大的处理,其0～20cm土层土壤的氯含量较基础土壤仅增加15～17mg/kg;施含氯化肥可使土壤pH值降低。因此,含氯化肥可以在甘蔗上使用,但在酸性土壤施用,应适当配合碱性肥料,防止土壤的酸化。     

云南甘蔗蓟马种类研究*

 甘蔗是云南主要的经济作物之一,蓟马类是甘蔗的重要害虫,以成虫和若虫集中在甘蔗未展开的心叶内危害,影响甘蔗产量。本研究调查云南省陇川、元江等17个甘蔗种植县、市,共采集成虫标本1142头。经鉴定,得出害虫种类9种,即蔗腹齿蓟马（又称甘蔗蓟马）（Fulmekiola serratus）、竹直鬃蓟马（Stenchaetothrips bumbusae）、黄蓟马（Thrips flavus）、褐蓟马（Thrips fusca）、黄胸蓟马（Thrips hawaiiensis）、花蓟马（Frankliniella intonsa）、禾蓟马（Frankliniella tenuicornis）、玉米黄呆蓟马（Anaphothrips obscurus）和华简管蓟马（Haplothrips chinensis）;天敌1种,即横纹蓟马（Aeolothrips fasciatus）。蔗腹齿蓟马（F. serratus）是所有甘蔗种植区的绝对优势种,在所调查甘蔗种植区均有,占所采集鉴定蓟马总数的80.21%。     

甘蔗收获机喂入分流系统的设计与试验

甘蔗收获机普遍使用的双圆盘切割台系统在收获过程中存在明显"居中堵塞现象"。为了合理利用收获机物流通道空间,使喂入的甘蔗流主动分流居中并行且均匀输出,设计了一种新型的甘蔗收获机喂入分流系统,通过三维设计软件Pro/E建立了甘蔗喂入分流机构虚拟样机模型,并导入多体动力学仿真软件ADAMS,在不同的分流转速、分流辊上的橡胶管按不同的角度安装及选择不同的橡胶管与甘蔗的摩擦因数进行了虚拟仿真试验并在仿真的基础上进行了物理样机实验。仿真与样机实验表明:当此机构分流辊机构转速为300r/min、分流辊上偏置胶管的偏置角度为30°,且偏置胶管与甘蔗间的静摩擦因数f0=0.3 5、动摩擦因数f1=0.2 5时,在保证甘蔗进给速度的前提下,可以使甘蔗流分布较为理想。