苹果缺钙对果实钙组分、亚细胞分布与超微结构的影响

 通过苹果幼果期果面喷钙获得试材,采用逐级提取法测定红富士和新红星两个品种贮藏过程中钙形态的变化;采用焦锑酸钾沉淀-透射电子显微镜观察方法,研究果实细胞中钙的亚细胞分布特点及其相应的超微结构变化。结果表明,随贮藏时间增加,红富士和新红星苹果果实水溶性钙和果胶钙含量下降,磷酸钙和草酸钙以及硅酸钙含量相应增加,与对照不喷钙比较,喷钙明显增加贮藏苹果果实各种形态钙的含量;品种间红富士苹果全钙及各种形态钙含量均显著高于新红星。钙均匀分布于细胞壁、细胞膜、液泡膜、核膜和核质,并在液泡内堆积;缺钙时核膜模糊或断裂,且钙颗     

7个梨主栽品种生长季钙含量的动态变化

缺钙会引起许多果实生理性病害。为给梨树合理补钙提供理论依据,以7个梨主栽品种为试材,研究了其叶片、果实和新梢钙含量的动态变化规律。结果表明：随着梨的生长发育,参试品种的叶片和新梢钙含量均大体呈增加趋势,果实钙含量呈逐渐降低趋势（其中幼果期至果实成熟前期降速最快）,且同一品种幼嫩器官与成熟器官的钙含量差异均达到了显著水平,同一发育时期相同器官钙含量最大值与最小值的差异也达到了显著水平。钙含量最高的器官是叶片,其次是新梢,果实钙含量最低。不同梨品种的钙素营养水平存在差异,其中各器官发育末期的钙含量,均以鸭梨最高,黄冠和大南果较低。     

柑橘园土壤·植株叶片及根的钙含量调查与分析

[目的]研究广西柑橘主产区耕层土壤、叶片和侧根中的钙含量现状及其之间的相关关系,为钙肥的合理施用提供理论参考。[方法]采集不同树龄的土壤、叶片和侧根样品,分析钙元素含量状况,并用SPSS软件进行统计分析。[结果]柑橘园土壤交换性钙含量范围为162~7 550 mg/kg,平均1 343 mg/kg,叶片钙含量范围为1.35%~5.29%,平均3.15%,侧根钙含量范围为0.45%~2.67%,平均1.28%;柑橘侧根钙含量随树龄的增长而增加,二者呈0.01水平显著的正相关关系,而果园耕作层土壤交换性钙、柑橘叶片钙含量与树龄之间相关性不显著,但与土壤pH的相关性在0.01水平显著;柑橘园耕作层土壤交换性钙、柑橘叶片及侧根钙的含量之间存在0.01水平显著的正相关关系。[结论]柑橘园土壤、叶片和侧根中的钙含量差异较大,大部分的土壤和叶片样品钙含量低于临界值。在柑橘生产中,应因地制宜合理施用钙肥。     

喷施不同钙肥对富士苹果果实品质和矿质元素含量的影响

[目的]研究喷施不同钙肥对红富士苹果品质、矿质营养元素含量的影响。[方法]以12年生红富士苹果为试材,于2011年盛花期(5月10日)、新梢旺长期(6月11日)、花芽分化期(7月10日)、果实膨大前期(8月7日)、果实膨大后期(9月7日)、果实成熟期(10月11日)7个时期采样并测定。[结果]在同一生理期内,SPAD值含量变化规律一致:以CK值最低,各处理大于CK,且各处理间差异性达极显著水平;从盛花期(5月)至果实采收后(11月),各处理SPAD值含量变化规律也一致,即由盛花期至果实膨大前期SPAD值含量逐渐升高,在果实膨大期至果实成熟期达到最高范围,果实成熟期后逐渐降低;各处理提高和维持SPAD值含量效果最佳为处理2、5(分别喷CaNO3、新禾丰果蔬钙肥)。喷施钙肥处理能显著提高富士苹果果实硬度、可溶性固形物含量、可溶性糖含量、单果重、套袋数目、单株产量等各项指标,但不同类型叶面喷施钙肥对提高富士苹果不同品质指标的效果也不同,其中处理4[喷施众德(康朴盖美膨)]对提高富士苹果品质效果最佳,处理3、8对提高其产量效果最好。各处理果实中元素含量顺序均表现为:K含量最高,其次是N、P,其他中、微量元素含量由大到小顺序分别为Mg、Ca、Fe、B、Zn、Cu。以Ca元素为中心,与果实品质、贮藏性密切相关的K、Mg与Ca呈正相关,其他各元素(除Cu外)与Ca也均呈正相关,其中Ca与K相关系数为0.74**,达极显著相关。各元素(除K、Cu)与果实硬度均呈正相关但均不显著;各元素(除Cu、Zn、B)与果实中可溶性固形物、可溶性糖含量均呈正相关,但仅Ca与可溶性固形物含量、P与可溶性糖含量正相关性达显著和极显著水平,其相关系数分别为0.63*、0.74**;各元素(除Cu)与单株产量均呈正相关,其中Ca、Mg与单株产量间正相关性达极显著水平,其相关系数分别为0.76**、0.80**。[结论]喷施钙肥能够显著提高富士苹果品质和同时对果实中各元素含量及其相关性也有影响。     

钙镁对甜瓜椰糠半基质栽培的影响

为了探索椰糠半基质条件下,钙镁肥对甜瓜产量、品质的影响,确定钙镁肥施用的必要性,配制不同钙镁含量的肥料进行比较。结果显示,不同钙镁含量的肥料与不含钙镁的肥料相比,产量、品质没有差异。在土壤水溶性钙1197.1mg?kg-1,水溶性镁690.8 mg?kg-1,灌溉水钙含量68.0 mg?kg-1,镁含量22.7 mg?kg-1的条件下,能为甜瓜椰糠半基质栽培提供足够的钙镁营养。这对简化施肥设施,减轻投入成本,加速该模式在中小企业及个体种植户中推广有较大的现实意义。     

Calcium nutrition of the sugarbeet

Abstract

When sugarbeet seedlings are transferred from a complete nutrient solution to one from which Ca has been withheld, the rootlets and tops fail to develop. The same transfer at the eight‐leaf stage causes the rootlets to become stubby and swollen at the tips and blade expansion becomes modified; particularly the upper portions of the blades attaining nearly full development, which pucker and often develop a cupping or hooding effect; a unique symptom characteristic of Ca deficiency. As each new leaf develops, the blade area becomes smaller until only a black tip remains at the apex of the petiole, which is the symptom referred to as tip‐burn for this petiole and the successively . shorter petioles formed as Ca deficiency increases in severity. Strangely, these symptoms also appear during periods of rapid growth when the nutrient solution contains as much as 10 to 28 milliequivalents per liter of Ca or when soils are high in Ca. This implies that Ca absorption and possibly translocation limits the Ca supply at the growing point. Increasing Mg in the nutrient solution decreases Ca uptake and increases Ca deficiency. Potassium deficiency, unexpectedly, induces Ca deficiency apparently by decreasing the translocation of Ca to the growing point.

These phenomena suggest the hypothesis that when ion absorption takes place from the root exchange site that has the affinity for H > Ca > Mg > K > Na, then the H generated internally replaces, and the roots absorb, Na, K and Mg preferentially. Externally, Ca would be adsorbed preferentially from the nutrient solution by the exchange complex, and with the addition of Mg, it would compete for the common adsorption site of Ca and limit Ca absorption internally. Under these conditions potassium‐deficient nutrient solutions would not induce Ca deficiency by decreasing Ca absorption but rather by decreasing Ca translocation. Theoretically, Ba would replace H more readily than Ca on the exchange complex, and therefore, Ba would be adsorbed preferentially and Ca uptake would increase. This effect of Ba was verified experimentally.

Since the translocation of ⁴⁵Ca to the growing point was found to be unrestricted under Ca‐sufficient and Ca‐deficient conditions and since the formation of insoluble Ca compounds such as phosphate or oxalate did not account for the Ca deficiency at the growing point, the cause of the Ca deficiency at the growing point is most likely the higher priority of the storage root for Ca over tops when leaf blades and storage root are both expanding rapidly. However, Ca retransport from older to younger parts of the sugarbeet plant may be restricted by the formation of Ca phosphate under Ca‐deficient conditions and Ca oxalate under Ca‐sufficient conditions.

Calcium deficiency increases net photosynthesis per unit blade area initially, probably because of blade puckering, but not on a per unit chlorophyll basis.     

高钾血症模型的建立及抢救措施机理的分析

高钾血症是临床上多种疾病所并发的一种常见病理生理过程。血钾升高的最大危害是心肌毒性,它可引起机体心律失常甚至心脏停搏危及生命。因此,预防高钾血症的发生和采取有效的处理方法,一直是病理生理学研究的热点问题之一。了解高血钾对心肌细胞的毒性作用及寻找抢救方法。制备高血钾家兔模型,并分别用葡萄糖酸钙、NaHCO3进行抢救。高钾血症时,心电图可见家兔心律失常,并且T波高耸,Q—T间期缩短,同时,还会使机体的呼吸系统发生变化;用葡萄糖酸钙、NaHCO3后,抢救成功。高血钾对心脏有毒性作用,浓度升高速度越快,毒性作用越大。静脉推注高葡萄糖溶液、NaHCO3溶液都对缓解高血钾症有一定的作用;心电图可作为诊断高血钾,判定其程度和观察疗效的重要指标。     

钙锌对蛋用型鸡育成期体组织中矿物元素含量的影响

试验研究了在玉米—豆饼型基础饲粮中添加不同水平锌和钙对蛋用型鸡育成期体组织中矿物元素含量的影响。结果表明,随着饲粮锌水平的提高,肝脏(P<0.01)、肾脏(P<0.05)、胰脏(P<0.01)中锌含量显著升高,而肺脏中锌含量没有显著变化(P>0.05)。饲粮高钙对组织中锌含量的影响未达到显著水平(P>0.05)。饲粮高锌使肝脏磷含量(P<0.05)、肾脏磷(P<0.01)和铜含量(P<0.05)、肺脏钙(P<0.01)和镁含量(P<0.01)显著降低。饲粮商钙使胰脏铜含量(P<0.05)显著提高,使胰脏锰含量显著降低(P<0.05)。     

Effect of dietary moisture and sodium content on urine composition and calcium oxalate relative supersaturation in healthy miniature schnauzers and labrador retrievers

The aim of this series of studies was to evaluate two possible feeding strategies as methods for reducing the risk of calcium oxalate (CaOx) formation in two breeds of healthy dog. The studies compared the effect of dietary moisture (Study 1) and dietary sodium (Na), (Study 2) on urine composition of labrador retrievers (LR) and miniature schnauzers (MS). A nutritionally complete dry dog food was fed to 16 dogs (eight LR, eight MS; Study 1) and 15 dogs (seven LR, eight MS; Study 2) for 24 days (Study 1), or 36 days (Study 2). The dogs were fed the diet alone (7% moisture, 0.06 g Na/100 kcal), or supplemented with deionised water to 73% moisture (Study 1), or dietary Na, to deliver 0.20 or 0.30 g Na per 100 kcal (Study 2). Urine pH, volume, specific gravity, and concentrations of 12 analytes were measured for each dog. Urinary relative supersaturations (RSS) with CaOx were calculated from these values. The effects of supplemental Na or water were established using t tests (Study 1) or analysis of variance, and multiple range tests (least significant difference) (Study 2); P<0.05 was considered significant. Increasing dietary moisture significantly increased total moisture intake (P=0.001), and reduced urine specific gravity (P=0.003), urinary oxalate concentration (P=0.04), and CaOx relative supersaturation (P=0.04) in the MS. Urinary parameters remained unchanged in the LR, indicating that feeding a high moisture diet may reduce the risk of CaOx formation in high-risk breeds. Increasing dietary Na led to production of urine with a significantly lower CaOx RSS in both breeds, indicating that sodium supplementation to dry diet formats may reduce the risk of CaOx formation. These feeding strategies should be considered when evaluating methods for preventing CaOx formation within high-risk groups.