Dolomitic limestone was more effective than calcitic limestone in increasing soil pH in an untilled olive orchard

In acid soils, when no-tillage farmers intend to apply lime, the question arises as to whether it should be incorporated into the soil or whether it can be left on the soil surface. In this study, two types of limestone, calcitic (Lcal) and dolomitic (Lmag), were tested in two olive groves of cv. Cobrançosa, with an initial pH of 4.9 (S. Pedro) and 5.5 (Raparigas). In S. Pedro, limestone was incorporated into the soil (Lburied) and in Raparigas, it was left on the floor (Lfloor). The use of limestone significantly increased soil pH in the 0–0.10 m layer in both experiments. In the 0.10–0.20 m soil layer, only Lmag increased significantly the soil pH in comparison with the control. Lmag was more effective than Lcal in increasing cation exchange capacity (CEC) and reducing exchangeable acidity (EA) and aluminium (Al³⁺) in the Lfloor experiment. Both limes increased leaf calcium (Ca) concentration, and Lmag increased the leaf levels of magnesium (Mg). In Lfloor experiment (higher soil pH), soil microbial carbon (C) decreased, and microbial nitrogen (N) increased with liming, which may indicate an increase in bacteria in the soil and a decrease in fungi. In Lburied experiment (initial pH of 4.9), liming significantly increased accumulated (2018–2021) olive yield (56 and more than 67 kg tree⁻¹, respectively, in the control and liming treatments). In Lfloor experiment (initial pH of 5.5), the accumulated olive yields did not differ significantly between treatments (average values between 105 and 115 kg tree⁻¹). The results of this study provide evidence that liming may increase olive yield in very acid soils and that dolomitic limestone should preferably be used by no-tillage farmers, due its higher solubility and faster effect on soil and trees.     

Drought stress tolerance and photoprotection in two varieties of olive tree

Abstract

The olive tree (Olea europaea L.) is adapted to tolerate severe drought and high irradiance levels. Relative electron transport rate (J), photosynthetic efficiency (in terms of F _v /F _m and Φ_PSII), photochemical (qP) and non-photochemical quenching (NPQ) were determined in 2-year old olive plants (cultivars ‘Coratina’ and ‘Biancolilla’) grown under two different light levels (exposed plants, EP, and shaded plants, SP) during a 21-day controlled water deficit. After reaching pre-dawn leaf water potentials of about -6.5 MPa, plants were rewatered for 23 days. During the experimental period, measurements of gas exchange and chlorophyll fluorescence were carried out to study the photosynthetic performance of olive plants. The effect of drought stress and high irradiance levels caused a reduction of gas exchange, J, Φ_PSII and F _v/F _m and this decrease was more marked in EP. Under drought stress, EP showed a higher degree of photoinhibition, a higher NPQ and a lower qP if compared to SP. Coratina was more sensitive to high light and drought stress and had a slower recovery during rewatering. The results confirm that photoprotection is an important factor that affects photosynthetic productivity in olive, and that the degree of this process varies between the cultivars. This information could give a more complete picture of the response of olive trees grown under stressful conditions of semi-arid environments, and could be important for the selection of drought-tolerant cultivars with a high productivity.     

Effects of High Boron Concentration and Scion-Rootstock Combination on Growth and Nutritional Status of Olive Plants

Own rooted olive plants (Olea europaea L.) of the cvs. ‘Megaritiki’ (M), ‘Chondrolia Chalkidikis’ (C), ‘Amfissis’ (A), ‘Kalamon’, ‘Koroneiki’, ‘Agiou Orous’, and wild olives, as well as the scion x rootstock combinations CxC, MxC, MxM, AxM, CxM, AxA, and CxA were irrigated with a nutrient solution containing 10 mg boron (B)/L for two months. In all the own rooted plants and in the rootstock—scion combinations of the same cultivar stem growth rate was decreased due to high B. The lowest B concentration in leaves and roots was found in ‘Kalamon’ and wild olives, respectively. ‘Megaritiki’ had higher leaf B concentration when grafted on ‘Megaritiki’ or ‘Chondrolia Chalkidikis’ compared to own rooted plants. The same cultivar as own rooted plant had higher root B concentration than as rootstock of the other tested cultivars.     

SEASONAL CHANGES IN LEAF NITROGEN OF OLIVE TREES GROWN UNDER DIFFERENT IRRIGATION REGIMES AND CROP LEVEL

An experiment was conducted over 12 months using field-grown olive trees (Olea europaea) to assess the combined effect of soil water availability and fruit number on seasonal changes in leaf nitrogen (N) concentration. Three irrigation regimes were established and three trees per irrigation treatment were thinned to reduce their yield to about half that of unthinned trees. The N concentration of fully-expanded leaves from either the current-year growth or one-year old part of fruiting shoots was determined every two months. Nitrogen concentration was higher in current-year leaves than in one-year old ones at most sampling dates. Maximum values of leaf N were measured in spring, minimum values in August. Leaf N concentrations were positively correlated with leaf water potential during fruit development. This relationship was weak at the onset of rapid oil accumulation in August and became more evident at harvest. There was no correlation between leaf N and crop level.     

油橄榄不同品种叶片中总黄酮提取工艺的比较

以油橄榄(Olea europaea L.)叶片为原料,以芦丁为对照品,先通过单因素试验、再采用正交试验优选总黄酮提取工艺,确定分光光度法作为测定方法,其选用Al Cl3作为显色剂,在波长415 nm、显色时间15 min条件下,对5个油橄榄品种叶片中的总黄酮提取量进行测定比较。结果表明,最佳提取工艺为提取溶剂90%(体积分数)乙醇、提取温度60℃、料液比1∶19、回流时间1.5 h。不同品种油橄榄叶片中总黄酮的提取量并不相同,在皮瓜尔(O.europaea cv.Picual)、科拉蒂(O.europaea cv.Coratina)、莱星(O.europaea cv.Leecio)、佛奥(O.europaea cv.Frantoio)、配多灵(O.europaea cv.Pendollin)5个品种中,以科拉蒂的叶片总黄酮提取量最高,莱星的含量最低。通过比较不同品种油橄榄叶片中总黄酮提取量的高低,为油橄榄叶片总黄酮的生产和应用提供了试验基础支撑,也将为当地的油橄榄综合开发提供技术保障。     

油橄榄中多酚类物质的研究进展

油橄榄富含多种功能活性成分,主要介绍了油橄榄中多酚类物质的含量特点、提取分离、分析鉴定和生物活性,以期为油橄榄的进一步开发利用提供参考.     

Effect of Soil Management on Olive Yield and Nutritional Status of Trees in Rainfed Orchards

Studies on the effect of groundcover treatments on perennial tree crops have been common in recent decades. However, few have included leaf analysis as an aid to understand the effects of groundcover treatments on tree crop growth and yield, in particular in rainfed olive orchards. Field experiments took place in northeast Portugal, over the course of eight consecutive years, in two commercial orchards selected on the basis of their contrasting situation regarding the floor-management system before the trial started. An orchard located in Bragança, currently managed as a sheep-walk, received the following treatments: sheep-walk (SW), where the natural vegetation was managed with a flock of sheep; mechanical cultivation (MC), which consisted of two tillage trips per year in the spring; and glyphosate (Gly), where the herbicide was applied once during the first fortnight of April. Another orchard near Mirandela, currently managed by tillage, received the following treatments: mechanical cultivation (MC); glyphosate (Gly); and residual herbicide (RH), where an herbicide with a residual component was applied late in the winter. The trees that underwent Gly treatments produced the greatest tree crop growth and olive yield. The worst results were achieved with the SW and MC treatments in the Bragança and Mirandela experiments, respectively. Leaf nitrogen (N) and boron (B) concentrations were significantly higher and lower, respectively, in the treatments that caused the higher and lower olive yields in both experiments. In the Mirandela orchard, where the leaf potassium (K) concentrations were close to the lower limit of the adequate range, the leaf K levels followed the pattern registered for N and B. The results showed a strong link between tree crop nutritional status and tree crop growth and olive yield. The groundcover treatments that facilitate nutrient absorption by olive trees yielded more crops.     

Dissemination of Pseudomonas savastanoi pv. savastanoi populations and subsequent appearance of olive knot disease

Pseudomonas savastanoi pv. savastanoi (Psv) is the causal agent of olive knot disease. The bacterium survives epiphytically and gains ingress through new wounds where infections and colonization result in knot formation. The natural spread of the bacterium and the subsequent appearance of the disease in olive orchards is poorly understood. The aim of this study was to monitor Psv epiphytic populations in inoculated plants with knots versus non‐inoculated healthy trees within the same orchard over four years. Additionally, disease severity was measured in both inoculated and non‐inoculated control trees. Epiphytic Psv populations moved from inoculated to non‐inoculated trees, although average Psv populations were higher in inoculated trees. Olive knot severity increased over the course of the study in all treatments and cultivars, with all plants reaching a high level of disease by the end of the study. However, the delay in the onset of disease was longer in non‐inoculated than in inoculated trees. Molecular typing of Psv isolates recovered from non‐inoculated control trees confirmed that they were similar to the inoculated strain. These data demonstrate that Psv can move over short distances in olive orchards through dissemination of epiphytic bacteria and suggest a relationship between the presence of epiphytic Psv and the number of knots on trees.     

近40年巴中地区油橄榄生长气候条件分析

基于线性倾向估计和多元非线性回归的理论,分析了巴中地区近40年的雨量、温度、日照的变化特征,同时结合油橄榄的生长习性对其进行了统计分析。结果表明,巴中地区近40年降水量的总体变化特征不是很明显,区域性变化不尽相同。年降水量的增多趋势对油橄榄生长的影响不大。年日照时数虽有下降趋势,但大致保持在1 400 h左右,对油橄榄的生长发育不会产生重要影响,影响油橄榄果实发育的关键时期（6～7月）的日照时数是略有增加的,这对油橄榄的生长是有利的。年均温度略有上升的趋势,将会促进该地区油橄榄的生长。综合以上气象要素的变化,巴中地区的气象生长条件对油橄榄生长是有利的,且在短时间内不会有较大的改变。     

油橄榄黄萎病及抗病育种研究进展

由土传性真菌大丽轮枝菌(Verticillium dahliae)引起的黄萎病(Verticillium Wilt),是世界范围内油橄榄种植区最严重的病害之一,降低产量并可导致树木死亡,由于该病原具有广泛的宿主,并能以其休眠体微菌核的形式在土壤中长期存活,并保持对寄主的侵染力,使得油橄榄黄萎病很难甚至无法防治。对其病害表现症状及发生特点、致病菌侵染特点、病害发生的影响因素以及抗病育种等进行了综述。