Effects of irrigation deprivation during the harvest period on leaf persistence and function in mature almond trees

In nut tree orchards in California, irrigation is typically withheld during the harvest period to reduce the likelihood of bark damage during mechanical shaking of the trees. The ensuing water stress, however, may result in premature defoliation and subsequent yield declines. Our objective was to establish and quantify the water stress resulting from irrigation deprivation and determine its impact on leaf function and persistence in mature almond trees (Prunus dulcis (Mill.) D.A. Webb cv. Nonpareil) during a 3-year field experiment. The severity of the water stress was characterized by measurements of predawn leaf (Psi(pd)) and midday stem (Psi(ms)) water potentials, stomatal conductance (gs), net CO2 assimilation rate (A) and leaf abscission. During 1995, Psi(ms) of fully irrigated (FI) trees was maintained above -1.0 MPa. In trees in the moderate- (MS) and severe-stress (SS) treatments, Psi(ms) was reduced to -1.4 to -2.0 MPa and -2.0 to -2.6 MPa, respectively. After 18 days of irrigation deprivation, A was reduced by 32 and 58% at midday and early afternoon, respectively, compared with morning values. A significant decrease in morning values of A only occurred after 30 days of irrigation deprivation. Water-use efficiency and A declined as evaporative demand increased from morning to afternoon. Assimilation also declined seasonally as leaves aged. Midday stem water potential was highly correlated with A, but less so with gs. The coefficient of determination between Psi(ms) and gs improved considerably when vapor pressure deficit and wind were multiply regressed with Psi(ms). Although A recovered rapidly when MS trees were irrigated, recovery in SS trees was slower and incomplete. Integrating the MS and SS effects for an extended period during 1995 resulted in 14 and 30% declines in A, and 6 and 20% declines in gs, respectively. The apparent Psi(ms) threshold for leaf abscission was -1.8 MPa. Daily canopy light interception declined with decreasing Psi(ms) as a result of premature defoliation (and perhaps altered leaf angles) from 67.9% in FI trees to 61.4 and 60.7% in MS and SS trees, respectively.     

板栗旋纹潜叶蛾生物学特性及防治

旋纹潜叶蛾Leucoptera scitella Zeller是危害板栗的主要害虫,在浙江省绍兴市1 a发生4代.以蛹在枝干树皮缝或枝叉处结茧越冬,翌年4月中旬越冬代成虫羽化并产卵,4月下旬第1代幼虫孵化,5月中旬幼虫老熟并结茧,5月下旬1代成虫羽化并产卵.6月上旬第2代幼虫孵化,下旬化蛹,7月上旬第2代成虫羽化并产卵,7月中旬第3代幼虫孵化,8月上旬化蛹、成虫羽化并产卵,8月中旬出现第4代幼虫,9月下旬开始结茧化蛹越冬.在第1代幼虫期,用1.8%阿维菌素乳油1 000倍液、5%吡虫啉乳油1 000倍液和生绿Bt可湿性粉剂800倍液喷雾防治,5 d后效果分别达到97.2%,98.0%和85.7%.     

Soil organic carbon stocks and fractions in different orchards of eastern plateau and hill region of India

Soil organic carbon (SOC) plays an important role in soil fertility and productivity. It occurs in soil in labile and non-labile forms that help in maintaining the soil health. An investigation was undertaken to evaluate the dynamics of total soil organic carbon (C _tot), oxidisable organic carbon (C _oc), very labile carbon (C frac ₁), labile carbon (C frac ₂), less labile carbon (C frac ₃), non-labile carbon (C frac ₄), microbial biomass carbon (C _mic) and SOC sequestration in a 6-year-old fruit orchards. The mango, guava and litchi orchards caused an enrichment of C _tot by 17.2, 12.6 and 11 %, respectively, over the control. The mango orchard registered highest significant increase of 20.7, 13.5 and 17.4 % in C frac ₁, C frac ₂ and C frac ₄, respectively, over control. There is greater accumulation of all the C fractions in the surface soil (0–0.30 m). The maximum total active carbon pool was 36.2 Mg C ha^?1 in mango orchard and resulted in 1.2 times higher than control. The passive pool of carbon constituted about 42.4 % of C _tot and registered maximum in the mango orchard. The maximum C _mic was 370 mg C kg^?1 in guava orchard and constituted 4.2 % of C _tot. The carbon management index registered 1.2 (mango orchard)- and 1.13 (guava and litchi orchard)-fold increase over control. The mango orchard registered highest carbon build rate of 1.53 Mg C ha^?1 year^?1 and resulted in 17.3 % carbon build-up over control. Among the carbon fractions, C frac ₁ was highly correlated (r = 0.567**) with C _mic.     

油茶树体氮磷钾养分的年动态变化

为给油茶生产中采取合理的生产栽培措施提供指导,提高油茶产量,改善果实品质,以普通油茶为材料,测定油茶植株生长过程中N、P、K元素在各部位的含量,研究其在油茶树体中的时空变化规律。结果表明:在油茶树体中,各营养元素总含量最大为K元素,N元素次之,P元素最少。从油茶叶片营养含量变化情况来看,3—5月,叶片吸收的N、P、K元素不断增多;6月,叶片N、P、K元素积累达到最大。从树体部位来看,果实需要养分最多。在生长发育过程中,果实对矿质营养的需求不同,K、N、P的需求量依次为31.60、17.11、7.90 g/kg。     

Analgesic and antidiarrheal properties of Ocimum selloi essential oil in mice

Ocimum selloi essential oil (2, 20, and 200 mg/kg; p.o.) reduced, in a dose-dependent way, the abdominal contraction induced by acetic acid (0.6%; i.p.) and the diarrhea episodes induced by castor oil in mice. At the higher dose (200 mg/kg; p.o.), the essential oil significantly reduced intestinal transit (P<0.05) in the charcoal meal test. The main component detected in O. selloi essential oil was methyl chavicol (98%; GC and GC/MS).These effects seems to support the use of O. selloi against diarrhea, intestinal spasm and visceral pain.     

城市公园树木白蚁危害及防治

温州市区9个公园的树木受白蚁危害比率为0~56.2%,其中翠微山公园和华盖山公园的树木受害最重。危害树木的白蚁共有2科4属5种,分别为黑翅土白蚁Odontoterms formosanus、黄翅大白蚁Macrotermtes barneyi、台湾乳白蚁Coptotermes formosanus、黄胸散白蚁Reticulitermes flaviceps和黑胸散白蚁R.chinensis。在调查的9个公园内共有29科37属41种树木受到白蚁危害,其中香樟、枫杨、构树、大叶桉、女贞等树木受害最为严重。采用草堆诱杀法及诱饵包诱杀法防治园林树木白蚁效果明显,在华益山公园,树木受害率从防治前的42.3%下降到5%左右。     

Photoperiodic control of seasonal development and dormancy in tropical stem-succulent trees

Tropical stem-succulent trees store large quantities of water in their trunks yet remain leafless during the early and mid dry season. In contrast to most other tropical trees, bud break of vegetative buds is not induced in fully hydrated stem succulents between the winter solstice and the spring equinox by leaf abscission, abnormal rain showers or irrigation. Vegetative buds of leafless trees are therefore in a state of endo-dormancy similar to that of temperate perennial plants during early winter. Highly synchronous bud break regularly occurs soon after the spring equinox, often weeks before the first rainfalls of the wet season. These observations suggested that endo-dormancy and bud break might be induced by declining and increasing photoperiods after the autumn and spring equinoxes, respectively. In phenological field observations, we confirmed highly synchronous bud break after the spring equinox in many trees of five stem-succulent species in the northern and southern hemispheres. Shoot growth of potted saplings of Plumeria rubra L. was arrested by a decline in day length below 12 h after the autumn equinox, but continued in saplings maintained in a 13-h photoperiod. Conversely, exposure to a 13-h photoperiod induced bud break of dormant apical buds in saplings and cuttings in January, whereas plants maintained in the natural day length of < 11.7 h remained dormant. Photoperiodic control of endo-dormancy of vegetative buds in stem succulents is thus supported by field observations and experimental variation of the photoperiod. At low latitudes, where annual variation of day length is less than 1 h, bud dormancy is induced and broken by variations in photoperiod of less than 30 min.     

绍兴市古树名木白蚁危害现状及防治对策

通过对绍兴市6县(市、区)古树名木白蚁危害情况的调查,查明危害古树名木的白蚁3科6种,其中黑翅土白蚁和黄翅大白蚁是优势种;古树名木受害率达25.1%以上;分析了易受白蚁危害的树种及古树名木受白蚁严重危害的原因;提出了相应的防治措施。     

柳州市园林树木及城市建筑白蚁危害调查及防治

柳州市城区危害园林树木的白蚁有3科4属4种,危害房屋建筑的白蚁有1科1属1种。调查23种园林树木中,有18种树木受到白蚁的危害,占78.26%,树木受害株率21.35%,严重受害株率4.16%;调查3 694家住户中,有861户受到白蚁的侵害,占23.31%,危害程度16.44%。台湾乳白蚁Coptotermes formosanus Shiraki是危害城区园林树木及房屋建筑的优势种,在272株受害树木中,有185株受台湾乳白蚁危害,在861户受害房屋建筑中,全部是受台湾乳白蚁危害。阴香、樟树、大叶桉、小叶桉、桃树等园林树木和房屋建筑内的木地板、墙裙、门、窗等木构件受到白蚁危害最为严重,建设健康"森林城市"必须同步抓好园林树木及房屋建筑白蚁防治。     

Composition and antifungal activity of the essential oil of Seseli annuum wild-growing in Serbia

The essential oil from the aerial parts of Seseli annuum, wild-growing in Serbia, was obtained by hydrodistillation and analyzed using GC and GC/MS. A total of 43 components were identified representing 96.5% of S. annuum oil. The most abundant compounds were germacrene D (29.8%), sabinene (10.3%), beta-ocimene Z (9.8%) and limonene (8.6%). The essential oil showed antifungal activity against fifteen fungi with MICs between 12.5 to 50 microl/ml.     

Characterization of endophytic bacteria with plant growth promotion and biological control potential isolated from walnut trees

In this study, a total of 68 endophytic bacteria were isolated from different tissues of walnut trees. About 55% and 22% of the strains had the ability to produce indole acetic acid and gibberellic acid, respectively. The capability of isolates to solubilize phosphate, growth on N‐free medium, siderophore, protease and lipase production was varied. Based on phenotypic grouping and plant growth promotion properties, twelve isolates were selected and 16S rRNA gene‐based phylogenetic analysis revealed that strains showed 99%–100% similarity to Pseudomonas, Bacillus, Arthrobacter, Roseomonas and Streptomyces genera. Amongst the selected strains, PS12, KS54, JS66 and KS74 showed root and shoot growth enhancement of poplar cutting. NS70, KS54 and PL36 strains showed antagonistic activity against Pseudomonas syringae pv. syringae;RR47, KS74 and NR69 strains had inhibition effects against Brenneria nigrifluens; and JS66 and RR26 strains had antagonistic activity against both phytopathogens under in vitro conditions. This is the first reported study to elucidate the endophytic bacterial diversity associated with walnut trees with beneficial attributes.     

湿地松等5树种在太湖滩地造林耐淹水性比较试验

在太湖滩地用湿地松、美国白蜡、水杉、池杉和柳树（对照）进行了不同树种、不同区域、不同淹水期和不同淹水深度的耐水湿对比造林试验。在淹水深度20～60．5cm、连续淹水时间达40d时观察结果为：①湿地松和柳树（对照）的成活率分别为99．7％和99．5％;美国白蜡、水杉和池杉的成活率分别为19．5％,30．2％和31．1％。②在太湖滩地湿地松表现与柳树（对照）一样,生长势和生长量一切正常,湿地松为常绿树种,病虫害较少,从绿化、美化和景观考虑,建议湿地松作为太湖滩地造林树种之一,并建议作为我国太湖地区淡水森林湿地植被恢复与重建的的适生树种之一。     

张家口市园林树木害虫危害规律与防治对策

为全面了解张家口市区园林树木害虫的种类、分布及其危害规律,给防治提供理论依据,作者采用踏查和标准地调查的方法对张家口市区内主要街道、公园及城郊周边绿化的园林树木害虫进行了全面调查。结果表明,张家口园林树林害虫群落共有5个目20个科38种,优势种集中于天牛、蚧虫、卷叶蛾等类群及天幕毛虫、舞毒蛾等。并对不同类群的害虫提出了综合防治对策。     

Outbreaks of the tentcaterpillar(Malacosoma neustria L.) on elm trees in Amsterdam and the efforts to control them with derris-powder

Ohne Zusammenfassung     

陕西渭北地区苹果园黑蚱蝉的产卵危害及其控制研究

选取渭南市白水县具有代表性的苹果园,对黑蚱蝉Cryptotympana atrata (Fabriciu)在果树枝条上的产卵危害规律进行了调查分析.结果表明:该地区苹果园最大受害株率可达94％,且受害株率与树龄成正相关;果树不同方位枝条受害程度与栽培走向密切相关;间作不同的果园受害差异不显著.黑蚱蝉趋向于在直径2.6～6.1 mm幼嫩枝条上产卵,产卵部位长度在5.8 ～35.2 cm之间,产卵部位基部与枝梢顶端的距离为10.8～56.2 cm;单枝平均刻槽数为35.1个,单刻槽平均卵量为6.8粒,单枝平均卵量为241.3粒.产卵枝条直径、产卵部位长度、单枝刻槽数和单枝总卵量两两之间均存在极显著相关性.应结合黑蚱蝉产卵规律,通过科学修剪、冬季深翻园土、喷施药剂等综合措施有效降低黑蚱蝉卵及若虫的数量,逐步控制该害虫对果园的危害.     

通道绿化林主要害虫及防治技术研究

对余姚市通道绿化林害虫的调查研究结果显示,重要绿化林带上的害虫共有318种,隶属于5目62科240属,其中有6种主要害虫：杨扇舟蛾、茶袋蛾、山东广翅蜡蝉、矩瘤蛎蚧、樟白轮盾蚧、红蜡蚧。防治强化预测预报集营林技术、生物与化学药剂的综合治理措施,能有效抑制通道绿化林虫害的发生。     

安岳县柠檬栽培管理及病虫害防治现状调查

安岳县是我国柠檬的主产地。该县柠檬产量占全国总产量的 70 %～ 80 % ,60年代中期安岳县出口的柠檬已经成为四川省外销柑桔的主要品种之一。曾经以其柠檬酸含量高、出油率高等优良品质 ,深受国内外市场欢迎。 1 986年 ,国家计委、农业部批准安岳县为全国柠檬商品生产基地县。柠檬已成为安岳县的第一支柱产业。近年来 ,该县柠檬出现了病虫害大量滋生危害 ,个别新发生病害成灾 ,控制困难、树势严重衰弱、出口果品农残超标等问题 ,极大的影响了柠檬产量和品质 ,制约着柠檬产业的发展。为了有针对性地解决以上问题 ,我们于 2 0 0 0年在龙台镇随…     

The tolerance of young trees to applications of clopyralid alone and in mixture with foliar-acting herbicides

The selective herbicide clopyralid is often used to controlcompeting Cirsium arvense in newly planted woodlands. When appliedas an overall spray at different dates in the spring (at 0.2kg acid equivalent (a.e.) ha^–1) to 10 tree species (Fraxinusexcelsior, Prunus avium, Quercus robur, Acer pseudoplatanus,Populus x canadensis cv. ‘Ghoy’, Pseudotsuga menziesii,Pinus nigra ssp. laricio, Larix kaempferi, Picea abies and Piceasitchensis) it did not reduce survival, and had little effecton growth. However, some species showed distortion of the youngestsprayed leaves or needles for several weeks after treatment,particularly F. excelsior, L. kaempferi and P. x canadensis.Sequential applications of clopyralid (first at 0.1 kg a.e.ha^–1 followed by 0.2 kg a.e. ha^–1 after 3 weeks),which are often required to control C. arvense, did not leadto increased leaf damage or growth reduction. Mixtures of clopyralidwith selective graminicides (cycloxydim at 0.45 kg active ingredient(a.i.) ha^–1; fluazifop-p-butyl at 0.38 kg a.i. ha^–1and propaquizafop at 0.15 kg a.i. ha^–1) did not causesignificant adverse effects on survival or growth of any species.If herbicides are required to control mixed stands of susceptibleproblem weeds such as C. arvense and grasses which are overtoppingyoung trees, these herbicide mixtures, applied as overall sprays,are less likely to cause damage to trees than attempts to usedirected applications of broad-spectrum foliar-acting herbicides.     

Nitrogen storage and its interaction with carbohydrates of young apple trees in response to nitrogen supply

Bench-grafted 'Fuji/M.26' apple (Malus domestica Borkh.) trees received a constant nitrogen (N) supply (10.7 mM) from bud break to the end of June, and were then fertigated with 0, 5, 10, 15 or 20 mM N in a modified Hoagland's solution for 2 months during the summer. In mid-October, half of the trees fertigated at each N concentration were sprayed twice with 3% urea, whereas the remaining trees served as controls. All trees were harvested after natural leaf fall and were stored at 2 degrees C. Five trees from each of the N treatment combinations were destructively sampled during dormancy to determine the composition of N and total nonstructural carbohydrates (TNC). As the N supply from fertigation increased, amounts of N in both free amino acids and proteins increased, whereas C/N ratios decreased. Foliar urea applications in the fall significantly increased amounts of N in both free amino acids and proteins, but decreased their C/N ratios. Arginine, the most abundant amino acid in both free amino acids and in proteins, accounted for an increasing proportion of N in free amino acids and proteins with increasing N supply from fertigation or foliar urea application. The ratio of protein N to free amino acid N decreased from about 27.1 to 3.2 as N supply from fertigation increased from 0 to 20 mM, and decreased further to 3.0 in response to foliar urea applications in the fall. Concentrations of glucose, fructose, sucrose and TNC decreased as the N supply from fertigation increased, whereas concentrations of sorbitol and starch remained relatively unchanged. Foliar urea applications decreased the concentration of each TNC component and the TNC concentration in each N fertigation treatment. A negative linear relationship was found between carbon in TNC and N in proteins and free amino acids. The sum of carbon in TNC, proteins and free amino acids remained constant in response to N supply from fertigation. However, foliar urea applications decreased the sum of carbon in proteins, free amino acids and TNC because about 21% of the decrease in TNC carbon was not recovered in free amino acids or proteins. Young apple trees store N and carbon dynamically in response to N supply. As N supply increases, an increasing proportion of N is found in the form of free amino acids, which have a low carbon cost, although proteins remain the main form of N storage. Furthermore, part of the carbon from TNC is incorporated into amino acids and proteins, decreasing the carbon stored as TNC and increasing the carbon stored as amino acids and proteins.     

无公害苹果园山楂红蜘蛛发生规律及防治措施研究

通过对无公害栽培苹果园山楂红蜘蛛发生分布规律及防治措施的研究发现，无公害栽培苹果园越冬态山楂红蜘蛛种群数量为平地园〉阳坡园〉阴坡园；越冬态山楂红蜘蛛在树体上集中分布在主干及第一层主枝的翘皮、环剥缝隙、剪锯口及气生根等处。从山楂红蜘蛛发生动态看，1a中有2次发生高峰，分别为3月底至4月初、6月底至7月初。早春彻底刮皮后，每株树上越冬态山楂红蜘蛛数量仅为未刮老翘皮树的3．77％；萌芽前喷5波美度石硫合剂防治越冬态山楂红蜘蛛，喷药7d后防效达90％以上；生长季应用1．8％阿维菌素3000倍液或24．5％绿维虫螨2000倍液控制山楂红蜘蛛危害的校正防效均在97％以上。