沉水植物对沉积物中铜锌铅的富集

选用4种南方常见水生植物(狐尾藻、轮叶黑藻、金鱼藻和水绵),以郴州重金属污染土样作为底泥,通过4种藻类单独及两两组合的水培方式,在室内模拟条件下培养1周,培养结束,比较各藻类的生长情况;经过浓盐酸+浓硝酸+高氯酸消化处理后,利用原子吸收光谱法测定藻体内铜锌铅3种重金属的含量。结果表明,单独培养和组合培养,藻体均有不同程度的增长,以狐尾藻的长势最好,狐尾藻+轮叶黑藻的培养中狐尾藻的生长百分比达到最大值65.7%。轮叶黑藻+水绵的组合方式可用于治理铜污染严重的区域,轮叶黑藻和水绵体内的铜含量可分别达到4.69mg/kg和20.13mg/kg,富集系数分别为0.041和0.178;金鱼藻+轮叶黑藻的组合方式可用于治理锌污染严重的区域,金鱼藻和轮叶黑藻体内的锌含量可分别达到139.96mg/kg和117.93mg/kg,富集系数分别为0.301和0.253;金鱼藻+狐尾藻的组合方式可用于治理铅污染严重的区域,金鱼藻和狐尾藻体内的铅含量可分别达到302.01 mg/kg和290.33mg/kg,富集系数分别为0.337和0.324;     

4种水生植物深度净化村镇生活污水厂尾水效果研究

通过设置动态模拟试验,持续进水、出水条件下分析比较了漂浮植物凤眼莲和水浮莲、沉水植物轮叶黑藻和挺水植物黄菖蒲对村镇生活污水厂(一级A标准)尾水深度净化效果,筛选出具有去污效果优势的水生植物,为优化水生植物生态修复工程技术在尾水深度净化中的应用提供依据。结果表明:经水生植物深度净化后,尾水水质得到明显改善,漂浮植物凤眼莲和水浮莲对尾水氮、磷的净化效果优于挺水植物黄菖蒲和沉水植物轮叶黑藻。试验周期内,污水厂尾水总氮、总磷和高锰酸盐指数(CODMn)平均浓度为12.22 mg?L-1、0.38mg?L-1和3.88 mg?L-1,凤眼莲、水浮莲、轮叶黑藻、黄菖蒲和对照各系统的总氮平均去除率分别为46.25%、45.74%、43.41%、38.39%和29.22%,总磷去除率分别为36.84%、34.21%、31.58%、28.95%和26.32%,CODMn去除率分别为42.27%、30.93%、32.47%、32.47%和37.89%。凤眼莲、水浮莲、黄菖蒲和轮叶黑藻生物量净增长率分别为550.5%、418.8%、210.6%和80.3%,凤眼莲生物量净增率最大。各处理系统内凤眼莲、水浮莲、黄菖蒲和轮叶黑藻对尾水氮富集量分别为7.36 g、2.33 g、5.12 g和4.46 g,对磷的富集量分别为0.60 g、0.19 g、0.33 g和0.78 g,凤眼莲富集氮能力优于另外3种水生植物,轮叶黑藻磷富集量高于另外3种水生植物。凤眼莲、水浮莲、黄菖蒲和轮叶黑藻植株吸收作用对尾水总氮去除的表观贡献率分别为15.29%、4.90%、11.17%和11.34%,对尾水总磷去除的表观贡献率分别为50.34%、17.17%、35.24%和76.34%。因此,可利用漂浮植物凤眼莲和沉水植物轮叶黑藻立体复合种养的方式深度净化生活污水厂尾水。     

沉水植物对再生水景观水体水质变化的影响和净化效果

为揭示沉水植物对以再生水作为水源的景观水体富营养化变化趋势的影响和对水体水质的维持和改善作用,对西安市一个再生水景观水体开展了不同区域和不同季节的水质监测试验,并采用室外玻璃缸装置研究伊乐藻和轮叶黑藻对再生水中氮、磷等营养盐的去除效果。结果表明:有沉水植物生长的区域氨氮、总氮浓度明显低于主湖区,且水质能够维持在低富营养化状态。伊乐藻和轮叶黑藻对再生水水质具有良好的改善作用,且伊乐藻优于轮叶黑藻。伊乐藻对再生水中CODCr、氮、磷的去除率分别为38.55%～57.54%,43.13%～51.81%和61.76%～77.45%,可使水体中叶绿素a含量维持在20μg/L左右,对藻类具有较好的抑制作用,可作为西北地区再生水景观水体水质修复的先锋植物。     

不同处理对核桃萌芽率、成枝力和着果的影响

通过对核桃轻截、中截、重截和长放几种修剪方法的研究,探讨了不同修剪强度对成枝长度、枝条粗度、萌芽率、成枝力的形响。结果表明:对水平枝中萌芽率最高的是中短截,为45.6%。45°短截对枝条萌芽率的影响中,中短截萌芽率最高,为45.1%。对水平枝发枝量影响中短截处理平均发枝数量最高,为3个。对45°枝条影响中长度最高的是中短截,为38.53 cm。     

非生长时期6种植物枝条的抗折力学特性

[目的]对内蒙古自治区中西部非生长时期6种植物枝条抗折力学特性进行研究,为该区防风阻沙植物种的选择及其混交配置提供生物力学方面的科学参考。[方法]采用YG(B)026 H-250型织物强力机和自制夹具,室内进行枝条抗折试验,比较6种植物枝条抗折力和抗折强度,分析枝长和直径对抗折力学强度指标的影响。[结果]①在0.5～2.5 mm测试径级范围,6种植物枝条抗折力随直径的增加而增大,抗折强度则随直径的增加呈幂函数递减;②在测试径级0.5～2.5 mm范围内枝长在60 mm时柠条枝条抗折力、抗折强度最大,其值分别为51.700 N和33.510 MPa,枝长在80 mm时种间抗折力、抗折强度最大为柽柳,其值分别为61.777 N和30.821 MPa,枝长在100 mm时种间抗折力、抗折强度最大为沙柳,其值分别是62.237 N和33.156 MPa。[结论] 6种植物枝条在非生长时期其抗折力和抗折强度随着直径、枝条长度的增加其变化特点表现不一致,表明植物种不同、枝长不同则对枝条抗折力、抗折强度的影响亦有差异,这也从另外一方面证明生态修复中只有实现多树种结合的修复方式才是最优水土保持功能实现的模式。     

6种连翘属植物在第四纪红壤上的生长适应性比较

为了丰富南方红壤侵蚀区水土保持植物资源库和改善其脆弱生态环境,以连翘(Forsythia suspensa)、秦连翘(Forsythia giraldiana)、卵叶连翘(Forsythia ovata)、东北连翘(Forsythia mandshurica)、金钟花(Forsythia viridissima)和垂枝连翘(Forsythia suspensa Vahl. var. sieboldii Zabel)6种连翘为试材,在南方第四纪红壤上开展了扦插种植试验;通过调查100 d后的幼苗成活率及植株生长状况,评估了它们的生长适应性。结果表明:(1)垂枝连翘平均存活率最高,达86.9%,其次为金钟花与连翘,分别为60.3%,56.5%;石灰表施、塑料覆膜、地膜+石灰表施3种种植措施可显著影响连翘属植物的成活率。(2)连翘品种对地下/地上生长指标均具有极显著的影响,而种植措施仅对地上部叶片具有极显著的影响,二者交互作用对除根系总长以外的3个生长指标均具有极显著的影响。金钟花的根系干重、根系总长、叶片干重和叶面积等指标值均最大,其次是连翘,而卵叶连翘所有指标均最小。(3)采用模糊数学隶属函数值法评价连翘属适应性结果表明:金钟花属于高度适应,连翘与垂枝连翘属于中度适应,秦连翘、东北连翘和卵叶连翘属于弱适应。因此,金钟花、连翘和垂枝连翘在第四纪红壤上引种栽种比较合适。     

塔克拉玛干沙漠头状沙拐枣光合器官生长对风蚀的 响应与适应策略分析

风蚀是沙区生态建设工程的重要危害形式。分析不同植物种生长对风蚀的响应和适应策略,确定其耐风蚀阈值,是优良耐风蚀生态建设植物种筛选的重要理论基础。本文以塔克拉玛干沙漠腹地纵向复合沙垄上栽植的头状沙拐枣人工林为研究对象,对不同风蚀深度植株的部分枝条节上和全株光合器官生长状况进行了观测和分析。结果表明,随风蚀强度增加,头状沙拐枣植株光合器官的单节同化枝数量、单节同化枝总长度和单根同化枝平均长度、单根同化枝平均重量、单株光合器官鲜重、单株同化枝表面积呈降低趋势,光合器官生长均与风蚀深度呈线性负相关。当风蚀深度小于40 cm时,头状沙拐枣的单节同化枝数量、单根同化枝长度、单节同化枝总长度降低幅度较小,但当风蚀深度大于40 cm后,单节同化枝数量、单根同化枝长度、单节同化枝总长度都大幅降低,全株光合器官的重量和表面积也大幅下降,而过强的风蚀可使植株死亡。头状沙拐枣光合器官对风蚀的适应方式是数量和形态变化,同化枝数量、长度、直径、表面积降低。对风蚀的适应策略是有限资源重点配置,即植株把能量主要分配在有限的节上,节上保持一定数量的光合器官生长,以维持植株存活。研究结果可为沙区生态建设适宜植物种筛选提供参考。     

冬枣秋季不同枝条叶施~(15)N-尿素的贮藏、分配及再利用

大田条件下,以6年生冬枣为试材,研究冬枣晚秋不同枝条叶施15N-尿素后,休眠期15N的贮藏、分配及翌年盛花期15N的再分配和利用。结果表明:晚秋叶施15N-尿素,休眠期树体枝干和根系中可检测到15N;翌年盛花期时,处理枝新生器官(枣吊、叶片、花)中可检测到15N。休眠期15N主要贮藏于地上部多年生器官,包括处理枝条和附近多年生器官。与休眠期相比,翌年盛花期时处理枝条的Ndff%显著下降,新生营养枝和多年生枝分别下降了59.13%和69.05%。贮藏15N再分配到新生器官,主要用于叶片和枣吊的生长,分配势随新生器官生理年龄的增加而增大(枣吊>叶片>花)。与新生营养枝处理不同,多年生枝处理的地上部枝干中贮藏15N向新生器官及枝干运输同时向下分配运输用于根系生长。     

基质、处理剂及其浓度对黑果枸杞硬枝扦插育苗的影响

[目的]探索黑果枸杞硬枝扦插育苗对土壤环境的选择性,为优质苗木的工厂化生产提供技术参考。[方法]以甘肃省永靖县黑果枸杞一年生枝条为材料,对4种土壤基质中不同生根粉(BBT)和萘乙酸(NAA)处理浓度下黑果枸杞硬枝扦插后的成活率、生长状况、生根率及根系性状进行了测定和评价。[结果](1)泥炭土、壤土、沙土均可用作黑果枸杞硬枝扦插基质,各浓度BBT和NAA处理下的成活率均分别在95%和80%以上;沙盐土不宜用于黑果枸杞扦插育苗;(2)扦插后第10周,生根率最高的是泥炭土,其次是壤土,沙土最低,但沙土中已形成的根系在后期表现出快速生长的特点。(3)新生枝条长度在扦插后的前5周增长缓慢,之后显著增加;随育苗时间增长,植株间枝条生长量出现明显差异。[结论]从透气性和根系发育来看,泥炭土硬枝扦插的效果最好。从保水性来看,普通壤土和沙土均较好,但沙土生根率低,不建议使用。     

可用于地被和微型盆栽观叶观花的堇菜植物——河南野生观赏植物（二）Ⅱ

9戟叶堇菜戟叶堇莱（Viola betonici- folia）为堇莱科堇菜属多年生野生宿根草本花卉。地下茎很短,无匍匐枝。叶基生,具长柄,条状披针形或条形，长2～9cm，基部稍下延于叶柄，截形或略带心形，有时稍成戟形，顶端钝或稍圆，边缘有疏而浅的波状齿，近基部的齿较深，两面近无毛或无毛，花期后叶增大，基部常有显著的垂片；托叶分离部分有疏齿。花具长梗，两侧对称；萼片5片，披针形，基部附器长约1mm，顶端圆；花瓣5片，淡紫色或少白色，距管状，顶端等粗，长3～4mm。果椭圆形，长约1cm，无毛。     

Standardization of Litchi Leaf Nutrient Composition for Tissue Analysis in Sub Tropics of India

ABSTRACT

Variation in leaf nutrient composition with leaf age and position of leaflets was assessed for ‘Calcuttia’ and ‘Dehradun’ litchi cultivars under loam to sandy loam soils of north India. Leaf samples were collected from first to sixth pair of leaflets starting from the apex of terminal shoots to downward positions during December to May at monthly intervals at two locations for three successive years. The leaves were analyzed for N, P, K, Ca, Mg, Fe, Zn, Cu and Mn concentrations. In both litchi cultivars, leaf N, P, Zn and Cu contents remained more in young leaves; whereas, leaf Ca, Mg, Mn and Fe contents were observed higher in older leaves. Leaf K concentration exhibited inconsistent patterns; however, leaf K concentration in pair of leaflets on the shoot declined basipetal, being maximum in upper pair of leaflets and minimum in lower pair of leaflets. Levels of macro and micronutrients exhibited a degree of stability at second and third pair of leaflets when sampled during February–March. Leaf compositions differed significantly during active vegetative growth, flowering, and fruit development. The results revealed that 4–5 months old leaves from autumn flush at second and third pair of leaflets from the apex of terminal litchi shoots at the advent of panicle initiation (February–March) should be collected to assess the nutritional concentrations of litchi orchards under North India conditions.     

Biomass and Accumulation of Potassium,Calcium, and Magnesium in Gladiolus as Affected by Heat Units and Corm Size

In México, gladiolus is an important crop cultivated in the central part of the country. In ornamental geophytes, the size of bulbs is a critical factor, impacting plant growth and quality. The objective of the present study was to model the accumulation of potassium (K), calcium (Ca) and Magnesium (Mg) in gladiolus plants as affected by corm size (3.5, 3.0 and 2.5 cm). Regardless of corm size, total dry mass of plants accumulated in three different stages. The initial stage occurred during the corm sprouting phase and continued through the vegetative phase, ending either shortly before (plants from 3.5 cm corms), at (plants from 3.0 cm corms) or shortly after (plants from 2.5 cm corms) the heading phase. The second stage, on which the plants exhibited a rapid dry mass accumulation, occurred shortly before or shortly after the heading phase, finishing with the elongation of the flowering stem. The third stage showed the highest dry mass accumulation rate, coinciding with the elongation of the flowering stem and ending at the blooming of the spike. To complete all the phenological phases, gladiolus required 1818 heat units regardless of corm size. Not considering the nutrients provided by the corm, gladiolus required a total of 6.33, 5.59 and 5.01 mmol plant^?1 of K, 2.22, 1.69 and 1.38 mmol plant^?1 of Ca and 2.49, 2.00 and 1.68 mmol plant^?1 of Mg when grown from 3.5, 3.0, and 2.5 cm corms. At the beginning of the vegetative phase, plants tended to increase Ca content at the expense of K, whereas the proportion of Mg remained unaffected, however, between the vegetative and heading phases, the proportion of Ca declined while that of K and Mg increased. At the end of the study, the proportion of K was much higher than that of Ca and Mg, whereas the proportion of Ca and Mg was similar.     

半日光间歇弥雾果树育苗系统及其应用

为解决某些果树树种繁育困难的问题,研制了半日光间歇弥雾果树育苗系统,用于甜樱桃矮化砧木吉塞拉6号嫩梢扦插育苗。通过对育苗环境主要因子的宽范围高精度调控,45 d育成新苗,生根率93.66%以上,每株平均生根7.29条,新苗移栽成活率95%以上。与传统扦插育苗和组培繁育相比,育苗周期和成本均显著降低。     

Intense fragmentation and deep burial reduce emergence of Rumex crispus L.

Abstract

Mechanical control through different tillage methods is a common measure against perennial weeds. However, non-optimal tillage can potentially increase the vegetative regeneration instead of reducing it. Aspects of regenerative capacity in the perennial weed species Rumex crispus L. was studied in three pot and box experiments as follows: (1) regeneration from different root fragments under varying test conditions; (2) effects of root size and burial depth on time of emergence and emergence rate; and (3) effects of burial depth and cutting on biomass production and seed production. In experiment 1, sprouting occurred mainly from the neck of the roots, consisting of underground stem tissue. A few shoots were observed also from the upper half of the true taproot and from a side root. No difference in sprouting was found between test conditions. In experiment 2, total emergence rate was positively related to root size and negatively related to burial depth. Time to first emergence was defined by an interaction between the two factors. Roots larger than 100 g gave rise to a high degree of emergence from all burial depths, while emergence from roots weighing 20–30 g was less than 30% from 12 cm and nonexistent from 18 cm. When emergence and shoot production were tested under different cutting regimes (experiment 3), the separated top fragments of the roots sprouted faster and produced more shoot biomass than intact rootstocks, even at a second harvest. Our results indicate that fragmentation can stimulate sprouting from the regenerative tissue of the taproot. Hence, if tillage is carried out as weed control it is important that root fragments are buried at ploughing depth, especially if the population consists of adult plants.     

Yield components and nutrients content in summer cover plants used in crop rotation in no-tillage system

This study aimed at identifying the proper developmental stage for the cutting of cover crops with high nutrients content in the shoots of plants to be used as green manure on crop rotation in the no-tillage (NT) system. Crotalaria juncea, Cajanus cajan, Mucuna aterrima, and Sorghum bicolor were collected at five different vegetative stages for assessing of fresh weight yield (DWY) and dry weight yield (DWY), as well as determining the carbon (C)/nitrogen (N) ratio and the contents of nutrients in the shoots of plants. The experiment was performed on a completely randomized design, with five replicates. Except for the nutrients contents in S. bicolor, for the assessed legumes the DWY, FWY, C/N ratio, nutrient concentration and nutrient accumulation in the shoots have increased with the development of plants. Therefore, it can be inferred that grasses studied will provide greater soil cover, while the legumes will provide a greater nutrient cycling.     

采伐干扰对东北温带次生林土壤碳矿化和活性有机碳的影响

在黑龙江东部的张广才岭选择典型次生杂木林进行不同采伐处理,一个生长季后测定了土壤潜在碳矿化速率和活性有机碳含量.结果表明:在28℃条件下经过90d的培养,土壤潜在碳矿化速率和碳矿化总量在所测定的土层中(0-10 cm,10-20 cm,20-30 cm)均表现为:50%强度采伐>皆伐后农作>25%强度采伐≌对照>皆伐后造林的变化趋势,但各处理间差异不显著.土壤易氧化碳含量在3个土层50%强度采伐均显著高于对照.土壤微生物碳含量在0-10 cm和10-20 cm土层,50%强度采伐显著高于对照.在0-10 cm土层,皆伐后造林显著低于对照.水溶性有机碳含量在0-10 cm和10-20 cm土层,50%强度采伐显著高于对照,在20-30cm土层,皆伐后造林显著低于对照,这说明在东北温带次生林中,较大强度的择伐短期内可增加土壤活性有机碳含量.而皆伐后造林可导致土壤活性有机碳出现下降趋势.     

EFFECT OF PETUNIA STOCK PLANT NUTRITIONAL STATUS ON FERTILIZER RESPONSE DURING PROPAGATION

Fertilization strategies during stock plant and cutting production are linked in terms of cutting nutrient levels and quality. Objectives were to evaluate (1) the effect of stock plant nutrition on tissue nutrient concentration and growth during vegetative propagation and (2) response to fertilizer during propagation for cuttings with 4 different initial tissue nutrient concentrations. ‘Supertunia Royal Velvet’ petunia stock plants were grown under constant fertigation of 0, 50, 100 or 200 mg nitrogen (N)^.L^?1 for 21 days. The 200 mg N^.L^?1 solution contained 150 nitrate (NO₃-N), 50 ammonium (NH₄-N), 24 phosphorus (P), 166 potassium (K), 40 calcium (Ca), 20 magnesium (Mg), 0.7 sulfur (S), 1.0 iron (Fe), 0.5 manganese (Mn), 0.5 zinc (Zn), 0.24 copper (Cu), 0.24 boron (B), and 0.1 molybdenum (Mo). Providing a complete fertilizer during propagation of petunia, beginning immediately after sticking of cuttings, reduces the risk of nutrient deficiency. Particularly in situations where fertilizer is not applied early during propagation, stock plants should be managed to ensure unrooted cuttings have adequate nutrient reserves.     

EARLY FLOODING OF TWO CULTIVARS OF TROPICAL MAIZE. II. NUTRITIONAL RESPONSES

The level of oxygen in soils affects the bio-availability of nutrients as well as the ability of root systems to uptake and transport water and mineral nutrients. However, efforts addressing management practices to reduce yield losses after transient flooding have had limited success. Since after-drainage nitrogen (N) fertilization has been proposed to mitigate crop damage, a closer examination of plant nutrient acquisition during this period is required. In this work, we compare the short-term changes in the tissue levels of macronutrients [N, phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] in two varieties of tropical maize differing in tolerance to poor soil drainage, after a six day period under water saturated conditions, early during the vegetative growth. Two Venezuelan varieties, one labeled as tolerant and the other as susceptible to limited soil drainage, were planted in 10-kg pots and flooded at the seventh-leaf-tip (V4) stage. Treatments included a post-drainage N fertilization. Plant responses were compared to corresponding non-flooded plants. Flooding the soil reduced concentrations of macronutrients in shoots, compared to well aerated plants. Calcium and Mg levels were also reduced in roots, whereas K concentrations increased. After a post-drainage recovery period, nutrient concentration in shoots of flooded plants were above those of non-flooded ones, due to higher uptake rates. The only exception was P, where reduced acquisition appears to limit plant recovery. A post-flood N-urea fertilization increased the concentrations of N, Ca and Mg in shoots, but failed to increase shoot growth after 15 days. Differences in the pattern of Ca accumulation suggested a possible role of Ca nutrition in the tolerance of maize to flooding.     

Reproductive phenology ofStenocereus gummosus (Engelm.) Gibson & Horak. Implications for its cultivation

Summary Stenocereus gummosus (“pitaya agria”, Cactaceae) is a wild native species of the Baja California Peninsula, Mexico. The fruit of these plants is harvested by ranchers for public consumption. There has been no attempt to cultivate this species or to enhance fruit production by selecting highly productive lines with desirable characteristics. Nevertheless, it is relatively easy to propagate asexually. Seed propagation is not practical in spite of its regular flower, fruit, and viable seed generation. Here, the “pitaya agria” was studied over 4 years (1988–1991) to generate basic information that may be useful for its induction to cultivation. A sample of plants was monitored during phenological events of budding, flowering, fruiting, and abortion. Among the results, we found that a third of the original buds developed into fruit, and the first 40 cm of the branches yielded more buds where the conversion into fruit was higher than in the rest of the branch. A statistical analysis revealed slight differences in the phenological events, despite dissimilar rainfall over the four years. In view of its successful asexual propagation, this species can be considered commercially promising.     

Propagule Quantity and Quality in Traditional Makushi Farming of Cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis>): A Case Study for Understanding Domestication and Evolution of Vegetatively Propagated Crops

Modeling how crop plants evolve under domestication requires estimating among-plant variation in important parameters of the reproductive system, including fecundity – the number of propagules produced – and propagule quality. Measuring these traits poses particular problems in vegetatively propagated crop plants. Unlike seeds, vegetative propagules are not intrinsic biological entities but are prepared by farmers. Propagule number and quality are thus determined by the interaction between plant traits and how farmers prepare propagules. We conducted observations, interviews and experiments to study this interaction in cassava grown by Makushi Amerindians, examining how both sources of variation, in plant traits and in farmers’ practices, combine to determine the number and quality of propagules produced. Increased stake mass, determined mostly by stem diameter, leads to increased yield and also to increased asexual ‘fecundity’ of the resulting plant. Farmers’ practices reflect knowledge of this relationship. Diameter is the key criterion in the selection of stems for stakes. Larger diameters are preferred; when thinner stems are used, stakes are cut longer, partially compensating for reduced mass. These results suggest that conscious and unconscious selection to increase ‘fecundity’ and propagule quality in cassava would act to favor plants with thicker stems. Mean stem diameter is greater, and variation in stem diameter is lower, in little-branched plants. Selection for increased asexual ‘fecundity’ can thus have led to reduction in the degree of branching, one of the most striking differences between domesticated cassava and its wild ancestors. Measuring variation in asexual fecundity is a key step in analyzing evolution of the mixed clonal/sexual reproductive systems that characterize many vegetatively propagated crop plants.