The role of calcium,boron and some divalent ions in leaf tipburn of strawberry

Strawberry leaf tipburn occurs commonly in some cultivars in Britain during the summer outdoors, although usually only mildly. Outbreaks are occasionally severe in glasshouses. The damage arises at the time of leaf emergence, but is most evident after leaf expansion.Although the disorder can be induced by deficiencies of boron or calcium in the rooting medium, it also occurs where these elements are freely supplied in nutrient solutions. Where neither calcium nor boron were deficient, drops of aqueous solutions of calcium salts (but not of boric acid) applied to buds and emerging leaves greatly reduced or prevented tipburn. Drops containing manganese, magnesium or strontium salts also reduced tipburn, while drops containing oxalate or citrate induced it. The addition of small amounts of EDTA to the drops decreased the effectiveness of the manganese, magnesium and, to a lesser extent, strontium salts, but not that of calcium nitrate.The evidence suggests that tipburn is caused by a localised shortage of calcium occurring just before and during leaf emergence, resulting either from a deficiency of calcium at the roots or, more frequently, from an inadequate rate of uptake or transport of calcium.     

Relationship between tipburn and leaf mineral composition in strawberry

Malformation of emerging leaves with distortion of leaf tips, a condition known as tipburn, is frequently observed in strawberry. Calcium (Ca) deficiency has been considered the main cause of tipburn. The aim of the present study was to analyse the relationship between leaf mineral composition and the incidence of tipburn in three short-day strawberry (Fragaria x ananassa Duch.) cultivars (‘Ventana’, ‘Camarosa’ and ‘Candonga’) submitted to different concentrations of Ca. The studies were conducted in a hydroponic system in a greenhouse. Calcium was added as Ca(NO₃)₂ at 2 mM, 3 mM, 4 mM and 5 mM. A completely randomized block design (4 Ca concentrations × 3 cultivars) with three replications was used. Each replicate consisted of 12 plants grown in a polyethylene bag (100 cm × 18 cm × 3 cm) filled with coconut peat. Crown diameter and tipburn incidence were evaluated throughout the experimental period, and at the end of the experiment leaf mineral composition was assessed. In general, plants with larger crown diameters had a greater incidence of tipburn. The ‘Candonga’ cultivar had the smallest incidence of tipburn, while the ‘Camarosa’ and ‘Ventana’ cultivars were more susceptible. There was no correlation between level of Ca applied and incidence of tipburn. The incidence of tipburn was associated with foliar K:Ca and K:Mg ratios. Ratios above 3.40 for K:Mg and 1.77 for K:Ca represented a risk of more than 50% of tipburn incidence, when overall means for all cultivars and levels of Ca were used.     

叶面喷施氯化钙对海南高温季节水培生菜生长生理的影响

为了探索高温水培环境下叶面喷施氯化钙对生菜生长生理的影响,以辛普森精英散叶生菜为材料,在35℃/25℃(昼/夜)下设置4个氯化钙浓度1、3、5、7 mmol·L-1处理,以清水为对照.结果表明,与对照相比,5 mmol·L-1氯化钙处理生菜最大叶宽、地上部鲜质量、地下部鲜质量和抗氧化酶活性均显著提高,丙二醛含量和叶片相...     

Expression of calcium sensing receptor during ischemia/reperfusion myocardial damage and relationship between CaSR and injury of myocardium

AIM: To investigate the expression of calcium sensing receptor(CaSR) during myocardial injury induced by ischemia/reperfusion and disclose the relationship between CaSR and myocardial ischemia/reperfusion. METHODS: The experimental model was established by the 30 min ligating and 1 h, 2 h, 4 h, 6 h reperfusing the left descending coronary artery (LAD) in rats. Wistar rats were randomly divided into 5 groups: sham group, ischemia/reperfusion 1 h, 2 h, 4 h, 6 h groups (I/R 1 h, 2 h, 4 h, 6 h group). CaSR mRNA expression was detected by RT-PCR. Left ventricular function was recorded. The levels of plasma lactate dehydrogenase (LDH), alondialdehyde (MDA) and superoxide dismutase (SOD) were measured. The change of ultrastructure in the ischemia/reperfusion myocardium of rats was observed by electron microscopy. RESULTS: LVSP,±dp/dtmax and SOD activity decreased gradually with the reperfusion time prolonged. LDH and MDA peaked at 2 h. The ultramicro-structural injury at the 1 h and 2 h was more serious than that at 4 h and 6 h. The expression of CaSR increased significantly after reperfusion of 1 h and 2 h, and decreased after 4 h and 6 h. CONCLUSION: The increased expression of CaSR mRNA and serious injure of myocardium were observed. CaSR may be associated with the myocardial ischemia/reperfusion injury.     

Effect of organic and inorganic fertilizers applied during successive crop seasons on growth and nitrate accumulation in lettuce

A romaine-type lettuce (Lactuca sativa L.) cv. Corsica was cultivated during three successive crop seasons (late-spring, late-autumn and late-winter) in the same soil of an experimental greenhouse in S.W. Peloponnese, Greece. Seven long-term fertilization treatments were tested for their effect on plant growth and nitrate concentration in the external lettuce leaves. Treatments included: three different doses of organic fertilization (composted sheep manure) applied at the start of each crop season, three different doses of inorganic N fertilization applied via fertigation during each crop season, and a control treatment in which no fertilizer was applied. A drip irrigation system was used to water all plants. The highest nitrate levels were observed in the medium and maximum inorganic fertilization treatments (572–664 mg kg⁻¹) in all crop seasons. They were significantly higher compared to the respective organic fertilization treatments (253–435 mg kg⁻¹) and all other fertilization treatments (148–435 mg kg⁻¹). Crop season affected lettuce growth more than nitrate accumulation in the lettuce leaves: lettuce biomass production was the smallest and most uniform in the late-autumn season and did not respond to the fertilization treatments tested (ranging from 409 to 439 g plant⁻¹), while in the late-spring season biomass production was the highest and most variable (561–841 g plant⁻¹), it correlated with nitrate concentration in the leaves and in the medium and maximum inorganic fertilizer doses it significantly exceeded production from all other fertilization treatments (827–841 g plant⁻¹). Following the three crop seasons the residual availability of N, P and K was clearly enhanced in the soil receiving the organic compared to the inorganic fertilization. Nitrate concentration in lettuce leaves was far below the upper limits set by the European Commission in all fertilization treatments throughout the three crop seasons, a result attributed mainly to the sufficient level of light intensity and duration throughout the year in Southern Greece.     

Studies on the relationship between leaf number and area and fruit development in mango (Mangifera indica L.)

The optimum leaf number: fruit ratio in various mango cuitivars was sought by isolating individual fruits with known numbers of supporting leaves by shoot girdling. ¹⁴CO₂ feeding experiments showed a higher rate of carbon fixation in the leaves of girdled shoots than of control shoots but the translocation of ¹⁴C assimilates to the developing fruits on the girdled and control shoots was comparable. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable to that of leaves on control shoots. In all the cuitivars studied it was observed that 30 leaves, the maximum available on a shoot, could not support the growth of a single fruit to normal size. The results also show that fruit development depends not only on the current assimilates but also to a great extent on reserves. The utilization of reserve metabolites from vegetative organs during the ‘on’ year could be a contributing factor towards biennial and erratic bearing.     

Nitric oxide accumulation and actin distribution during auxin-induced adventitious root development in sunflower

Auxin-mediated adventitious root (AR) formation from the basal ends of hypocotyl segments in sunflower (Helianthus annuus L., cv. Morden) is associated with gradual subcellular and anatomical changes. Pre-mitotic events (induction phase) are evident within 1 d (24 h) in the interfascicular parenchyma. Evidence for nitric oxide (NO) accumulation in the interfascicular cells 2 d after indole-3-acetic acid (IAA) treatment, highlights the involvement of NO specifically during root initiation, following AR induction phase. Thus, adventitious root induction and initiation can be distinguished as NO-independent and NO-dependent phases. Treatment of hypocotyl explants with 10 μM 1-napthylphthlamic acid (NPA), an inhibitor of polar auxin transport in plant cells, leads to complete abolition of NO-associated fluorescence, detected upon incubation of hypocotyl sections with 4,5-diaminofluorescein diacetate (DAF-2DA). This indicates a signaling link between auxin transport and NO accumulation in the target cells. Latrunculin B (Lat B), an actin depolymerizing agent, leads to substantial inhibition of IAA-induced AR response and NO accumulation in the responding cells. Aminoguanidine [an inhibitor of inducible form of nitric oxide synthase (iNOS)] brings about a reduction in the tissue NO content, indicating a significant activity of putative NOS leading to endogenous NO accumulation. Confocal laser scanning microscope (CLSM) imaging has revealed bundling of actin with NPA and Lat B treatments. A probable interaction is thus evident between actin and NO during auxin-mediated AR formation in the initiation and extension phase. Present work, thus, provides novel observations on an interaction among endogenous NO, IAA and actin at specific stages of AR formation.     

Canopy profiles of starch and leaf mass per area in greenhouse tomato and the relationship with leaf area and fruit growth

Better knowledge of patterns of carbon allocation in plants growing in CO₂-supplemented atmospheres may help to guide more efficient management of CO₂ applications in tomato greenhouses. Leaf starch and LMA (leaf mass per unit area) were investigated in commercially grown greenhouse tomato plants to determine the distribution and influence of leaf area and fruit load on these measures.     

杨梅果实发育与糖的积累及其关系研究

以东魁、荸荠种、水梅为试材,研究了杨梅果实发育与糖积累及其关系。根据杨梅果实大小的增加将果实发育大致分为3个阶段,呈双“S型”曲线动态变化:第1阶段(约盛花32d前)果实纵、横径增长最快;第2阶段(32-63d)果核发育硬化,果重增加明显;第3阶段(63d至成熟)果实进入快速增长高峰,果重迅速增加,光合产物在果实中迅速积累。杨梅果实中积累的糖主要是蔗糖,果糖和葡萄糖仅占总糖的1/4,蔗糖含量在发育初期和中期都较低,盛花52d后开始快速积累直至果实成熟,东魁高于水梅、荸荠种;葡萄糖和果糖变化大致保持同步,第1阶段较高,第2阶段降到最低,第3阶段迅速积累达到最高,与蔗糖积累基本保持一致,成熟时东魁与水梅较荸荠种高且相近。杨梅果实中酸性转化酶(Ivr)与中性转化酶(Nvr)活性变化趋势相同,幼果早期最高,中期降低后维持较低活性直至成熟。品种间pH值变幅相似,果实发育第1阶段最高,第2阶段降到最低,转色后上升。相关分析表明:果实发育动态与蔗糖、葡萄糖、果糖的积累存在着极显著的相关关系,其中果实横径的增加与果实糖积累组分中蔗糖的变化2者间相关性最大(r=0.93255**)。     

石榴开花期叶面积指数与坐果率的关系

石榴为石榴科石榴属植物。在我国栽培已有2000年以上的历史,是我国古老的栽培果树之一。其作为栽培的只有一个种,即石榴（Punica granarum L．）。石榴树适应性强,易栽培,易管理。它集食用、药用和观赏于一身,在国内外有着广阔的消费市场。石榴在我国有六个生产区,即陕西临潼产区、山东枣庄产区、安徽怀远产区、四川会理产区、云南产区和新疆叶城产区。在西昌,石榴也是果树主栽品种,为西昌果农创造了丰厚的收入。     

钙素营养与套袋苹果苦痘病的关系

为了探讨苹果套袋后苦痘病加重的原因,以富士苹果为试材,对果实发育过程中钙、氮含量的变化规律,果实幼果期和成熟期钙总量,套袋后果实微环境湿度变化及不同有机质果园苦痘病发生率进行了测定。结果表明,未套袋苹果果实在幼果期吸收钙量占成熟果实总钙量30%左右,后期占70%左右,套袋影响了果实对钙的吸收;套袋使袋内湿度增加,果实表面蒸腾作用降低,使果实对钙的吸收受到影响;同时套袋果氮含量一直高于未套袋果,N/Ca增大,促成了苦痘病的发生。增加果园有机质含量,可以改善根际钙离子供应,降低苦痘病的发生。     

The study on the relationship between transforming growth factor-β1 and lung carcinoma

AIM: To explore the relationship between the expression of transforming growth factor-β1 (TGF-β1) and the pathogenesis of lung carcinoma, and the influence of radiotherapy on plasma TGF-β1 level of patients with lung carcinoma. METHODS: By immunohistochemical method, the expression of TGF-β1 was examined. An enzyme-linked immunoadsorbent assay (ELISA) was used to quantify the plasma TGF-β1 levels in different time as before radiotherapy, at the end of radiotherapy, and at the time of follow-up 6 months after radiotherapy, respectively. The changes of quantity of TGF-β1 in different time above were analysed statistically. RESULTS: There was a significant increase in TGF-β1 expression in the carcinoma compared with normal lung tissue. The mean TGF-β1 level in the 39 lung carcinoma patients before radiotherapy was (11.0±1.5) μg/L, which was significantly higher than control group (3.8±0.2 μg/L) (P＜0.05); but the plasma TGF-β1 level after radiotherapy was significantly lower (5.6±0.5 μg/L) compared with the level before radiotherapy (P＜0.05), and there was not significant differences compared with control group (P＞0.05). At the time of follow-up 6 months, the patients of lung carcinoma had a significantly higher plasma TGF-β1 level (11.3±1.2 μg/L) compared with the level at the end of radiotherapy (P＜0.05), but there was not significant differences compared with before radiotherapy (P＞0.05). Not significant difference was found in TGF-β1 levels among different histologic types. CONCLUSION: These data demonstrated that TGF-β1 was associated with the pathogenesis of lung carcinoma, and it may be a useful tumor marker in patients with lung carcinoma.     

Relationship between early watercore development and leaf photosynthesis or partitioning of photosynthates in apple

Seasonal changes in leaf photosynthetic rate and partitioning of ¹³C taken up by leaves were compared in relation to the development of early watercore using susceptible ‘Orin’ and resistant ‘Fuji’ apples (Malus domestica Borkh.). There was no difference between the cultivars in leaf photosynthetic rate from mid-July to mid-October. The extent of watercore in ‘Orin’ increased from mid-July and peaked in late-August, followed by a decrease through mid-October, while no watercore was detected during the experimental period in ‘Fuji’. Fruit fresh weight and soluble solids content (SSC) were higher in ‘Orin’ than ‘Fuji’ during the earlier stages. Leaf dry weight of ‘Orin’ was higher than that of ‘Fuji’ throughout the experimental period. Accumulation of dry matter in the fruit increased in both cultivars and ‘Orin’ kept significantly higher level than ‘Fuji’ from mid-July to mid-October. The amount of ¹³C distributed to ‘Orin’ fruit at 5 days after labeling was significantly higher than ‘Fuji’ in mid-July just before watercore started to occur. ¹³C taken up by ‘Orin’ fruit with prevalent watercore was also higher than ‘Fuji’ in late-August but the difference was not significant. In mid-October when early watercore was gradually reducing, ¹³C recovered by ‘Orin’ fruit decreased and was significantly lower than ‘Fuji’. The difference of partitioning pattern of ¹³C between the cultivars was associated with the susceptibility to early watercore as well as the changes in fruit growth and SSC. The seasonal changes in the amount of ¹³C distributed to ‘Orin’ fruit were also related to the fluctuations in watercore severity. The results suggest that active phloem transport might be the cause of early watercore in our previous work, which might be induced by the increased partitioning of assimilates to the fruit during summer in susceptible ‘Orin’ compared to resistant ‘Fuji’ and not by the higher potential of leaf photosynthesis.     

The relationship between pod yield and specific leaf area in snapbeans; an example of stepwise multiv ariate analysis of variance

After a detailed (univariate) analysis of variance, stepwise multivariate analysis of variance (stepwise MANOVA) was used on the experimental data obtained from an investigation with snapbeans (Phaseolus vulgaris L.), carried out in the arid regions of Shambat (Sudan). The purpose of the experiment was to examine the relationship, if any, between pod yield and SLA for 3 snapbean cultivars and 4 sowing-dates. Four variables over plots were considered, viz. the yield earliness, the total yield, the SLA earliness and the average SLA. From a stepwise MANOVA, it appeared that the “cultivar” effect was primarily expressed by yield earliness and total yield. SLA earliness and average SLA provided no additional “cultivar” effect. Furthermore, the “sowing-date” effect could be expressed mainly by SLA earliness and yield earliness. Finally, the interaction effect played a minor part compared with the “sowing-date” and “cultivar” effect.     

The protean relationship between boreal forest landscape structure and red squirrel distribution at multiple spatial scales

This paper investigates two fundamental questions in landscape ecology: what influence does landscape context, or the composition of the matrix, have on an animals’ response to landscape structure, and how does this relationship extrapolate between landscapes? We investigate how the distribution of North American red squirrels (Tamiasciurus hudsonicus) in the boreal mixedwood forest is influenced by anthropogenically (forest harvest) and naturally (forest fire) derived landscape structure. We studied the presence and absence of red squirrels over two years in three landscape types: one managed for timber harvest, one recently burned by wildfire, and a third unburned unmanaged landscape. Landscape composition and configuration, measured at several spatial scales, predicted red squirrel’s distribution in all three landscapes, but the significant landscape variables changed across spatial scales, across time, and across landscapes. These findings emphasize the variability in landscape structure/animal distribution relationships, and enforce the need to link pattern-finding studies, such as this one, with searches for the mechanisms behind the observed pattern.     

An investigation of the relationship between reproductive growth and yield loss in hazelnut

This study was carried out in Samsun during a 2-year period to examine the relationship between reproductive and yield loses in the ‘Tombul’ and ‘Palaz’ hazelnut cultivars. In hazelnuts, male and female flowering occur in winter after the breaking of inflorescence dormancy. In the present study, growth of the ovary of the hazelnut started in April and continued until mid-June. At the time of flowering the ovary did not form. The ovule growth showed a rapid increase at the end of June. Change in the diameter of the ovary and ovule with time showed a simple sigmoid growth curve. Fertilization occurred during the period between mid-May and the beginning of June, namely, 3.5–5 months after pollination. At this time, the diameter of the nut was 9.54 mm. Twin kernel was not observed. The ratio of double kernels was close to zero. The time period from fertilization to harvest was 89 days in 1997 and 96 days in 1998 for Tombul cultivar. For the Palaz, this period was 84 days in 1997 and 86 days in 1998. The rate of pistillate flower clusters which dropped in April–May was more than those dropped in June–August.     

Interaction between STIM1 and Orai1 in calcium-sensing receptor-mediated calcium influx and nitric oxide generation

AIM: To investigate the interaction of Ca²⁺-sensing proteins, stromal interaction molecule 1 (STIM1) and calcium release-activated calcium channel protein 1 (Orai1), in Ca²⁺-sensing receptor (CaSR)-mediated extracellular Ca²⁺ influx and production of nitric oxide (NO). METHODS: Human umbilical vein endothlial cells (HUVECs) were incubated with CaSR agonist spermine [activating store-operated calcium channels (SOC) and receptor-operated calcium channels (ROC)] alone or combined with CaSR negative allosteric modulator Calhex 231+ROC analogue TPA (activating ROC, blocking SOC), protein kinase C (PKC) inhibitor Ro 31-8220, or PKCα/β1 selective inhibitor Go 6976 (activate SOC, blocking ROC). The protein expression of STIM1 and Orai1 was determined by the method of immunofluorescence. The interaction between STIM1 and Orai1 was examined by co-immunoprecipitation. The second to third passages of HUVECs were divided into STIM1 and Orai1 short hairpin RNA group (shSTIM1+shOrai1 group), vehicle-STIM1+vehicle-Orai1 group and control group, and then incubated with the 4 different treatments above. The intracellular Ca²⁺ concentration ([Ca²⁺]_i) was detected using the fluorescent Ca²⁺ indicator Fura-2/AM. The production of NO was also determined by DAF-FM DA fluorescent probe. RESULTS: The protein expression of STIM1 and Orai1 was located in the cytoplasm. Compared with control group, the localization of STIM1 and Orai1 in the cytoplasm was reduced after the HUVECs were incubated with Calhex 231+TPA, Ro 31-8220 or Go 6976, and the interaction of STIM1 and Orai1 was decreased significantly. The [Ca²⁺]_i and the net NO fluorescence intensity in shSTIM1+shOrai1 group were significantly reduced after the 4 different treatments (P<0.05). CONCLUSION: STIM1 and Orai1 are components of SOC and ROC in store-and receptor-operated Ca²⁺ entry and NO generation.     

Nickel supplementation effect on the growth,urease activity and urea and nitrate concentrations in lettuce supplied with different nitrogen sources

Effect of nickel (Ni) in the nutrient solution on yield, N metabolism, and nitrate content of leafy vegetables is poorly understood. The aim of this nutrient solution culture experiment was to investigate the effects of Ni supplementation on the nitrogen (N) metabolism and growth of lettuce (Lactuca sativa L. cv. Baker) with either urea or nitrate as the N source. Nickel supplement at 0.04 μM reduced urea toxicity to the urea-fed plants. Addition of Ni to the nutrient solution significantly increased the leaves and root growth of the urea-fed lettuce plants while it increased the growth of lettuce plants fed with nitrate only at N level of 20 mM. At N level of 20 mM, the leaves fresh weight of the urea-fed plants promoted by Ni supplement was comparable with the nitrate-fed plants untreated with Ni. Nickel supplementation increased the leaf total N concentrations in the urea-fed plants, although the nitrate-fed plants accumulated greater N in their leaves compared with urea treated plants at without Ni treatment. Nickel addition decreased the concentrations of leaf urea-N in the urea-fed plants and NO₃-N in the nitrate-fed plants. Nickel addition enhanced urease activity in the leaves of urea-fed plants. The results indicated Ni supplementation enhances the growth of the urea-fed lettuce plants while it has role in decreasing leaf nitrate concentration and thus, improving the health quality of the nitrate-fed plants.     

Combined effects of leaf/fruit ratios and N and K fertigation levels on growth and distribution of nutrients in pot-grown persimmon trees

Responses of pot-grown persimmon trees (Diospyros kaki cv. ‘Fuyu’) with two different leaf/fruit (L/F) ratios and three different fertigation levels were studied. On July 2, the L/F ratios of 4-year-old trees were adjusted to 20 and 10 by fruit thinning. From July 4 to August 26, each pot was fertigated with a solution containing 0–0 g (none), 10–8 g (medium), or 20–16 g (high) of nitrogen (N) and potassium (K), respectively. The L/F ratio of 10 resulted in higher yields but smaller fruits containing lower soluble solids than the ratio of 20. The non-fertigated trees with the L/F ratio of 10 produced the smallest fruits, but the medium fertigation increased the size of the fruit at this ratio. The high fertigation level decreased fruit skin color at both ratios. Fruit dry weight increased the most among the tree components, accounting for 48–57% of the tree total dry weight at the L/F ratio of 20 and for 64–72% at the ratio of 10. The increase in tree total dry weight at the ratio of 10 was greater than that at the ratio of 20. The trees receiving medium fertigation had higher tree total dry weights than those receiving high fertigation, especially at the ratio of 10. As the L/F ratio changed to 10 from 20, the percentages of N and K partitioned to fruits in the non-fertigated trees increased from 38% to 51% and from 67% to 96%, respectively, of the tree total N and K increases; the percentage decreased with increasing fertigation level. Although fertigation significantly increased total N and K contents of the tree, the increase in K at the ratio of 10 was less in high fertigation rather than in the medium level. The results indicated that adjusting supplemental N and K was necessary to ensure fruit growth and N and K accumulation for trees with high fruit loads, but high levels of fertigation are not necessarily preferable.