西葫芦不同节位叶片的形态解剖学数量性状研究

在自然条件下,对西葫芦幼苗不同节位叶片的形态解剖结构进行了研究.结果表明:节位由上至下,叶片上、下表皮细胞密度及气孔密度呈下降趋势,表皮细胞及气孔大小呈上升趋势,上部叶片栅栏组织厚度与下部叶片栅栏组织厚度之间存在极显著差异,栅栏组织厚度与海绵组织厚度比值在0.84～0.88之间.不同节位之间西葫芦单叶重、叶长及叶面积之间具有极显著相关性.     

大花萱草对水分胁迫的光合响应

对黄色(T1)、金黄色(T2)和红色(T3)3个不同大花萱草的品系进行水分胁迫,利用CI- 340便携式光合仪测定了其水分胁迫下叶片的光合特性.结果表明:3种大花萱草的光合速率日变化呈双峰曲线,在中午有明显的“午休”现象,干旱处理下的3种大花萱草光合速率明显低于对照;随胁迫程度的增大,各品系的光合速率均呈缓慢增加然后迅速降低的变化趋势,T1黄色品系表现出较强的光合能力,T3红色品系其次,T2金黄色品系的光合能力表现最弱.     

叶片微形态结构特征与柑桔溃疡病抗性的关系

为了研究叶片微结构特征与柑桔溃疡病抗性的关系,选择对柑桔溃疡病具有高抗(罗浮金柑)、抗(新生系3号椪柑)、耐(纽荷尔脐橙)和高感(星路比葡萄柚)特性的4个品种为试材,在室内涂抹接种验证抗病性的基础上,采用扫描电镜及树脂包埋半薄切片等技术对成熟叶片的解剖结构及下表皮进行观测,并采用细菌分离法测检各品种健康叶片浸泡接种病菌侵入数量.结果表明:4个品种对柑桔溃疡病抗性差异明显;叶片浸泡接种病菌侵入数量与品种抗性密切相关,依次为星路比葡萄柚＞纽荷尔脐橙＞新生系3号椪柑＞罗浮金柑;不同品种的气孔密度、气孔大小、叶片厚度、栅栏组织厚度、海绵组织厚度和下皮层厚度存在差异,但是只有气孔密度与抗性之间能呈现出有规律的对应关系;气孔密度可作为柑桔植株抗柑桔溃疡病早期选择的辅助形态指标.     

葡萄砧木抗旱性的叶片解剖学研究

该试验采用组织解剖学调查法,对16种葡萄砧木的抗旱性与叶片解剖结构的关系进行了研究.结果表明:气孔密度、叶片组织紧密度、角质层厚度与抗旱性正相关,而气孔大小、叶片上表皮细胞大小与抗旱性负相关.     

袖叶片与抗旱性相关的解剖结构指标研究

以柚为试材,测定了10个品种柚的叶片厚度、上表皮厚度、下表皮厚度、栅栏组织厚度、海绵组织厚度、叶片组织结构紧密度、气孔纵径、气孔横径、气孔大小、气孔密度和气孔相对面积,采用隶属函数分析法进行柚不同品种的抗旱性分析。结果表明:10个品种在各项叶片解剖结构指标上差异极显著。对11个抗旱指标进行了主成分分析和隶属函数分析,10个品种的抗旱性大小排序为:左氏柚>矮文柚>东风早柚>虎蜜柚>脐柚>华蓥山柚>通贤柚>梁平柚>早熟柚>强德勒。     

低温弱光对西葫芦叶片解剖结构的影响

研究了不同温度和光照条件对西葫芦幼苗叶片解剖结构的影响。研究结果表明,低温弱光处理使得西葫芦叶片上下表皮细胞密度、细胞直径、气孔密度以及气孔长度均变小,叶片厚度变薄,栅栏组织厚度及叶片厚度均减小,海绵组织也变得更为疏松,栅栏组织/海绵组织的比值减小,细胞间隙变大。     

蓝莓叶片与抗旱性相关的解剖结构指标研究

为用叶片解剖结构指标评价蓝莓(Vaccinium spp.)的抗旱性提供科学依据,并为蓝莓抗旱性品种的选育提供便捷有效的方法,测定分析了蓝莓8个品种的7项与抗旱性相关的叶片解剖结构指标,分别为叶片主脉直径、叶片厚度、上表皮厚度、上表皮角质层厚度、栅栏组织厚度、叶片组织结构紧密度和气孔密度。方差分析结果显示,8个品种在每项叶片解剖结构指标上总体差异均为极显著。对各品种进行了两两之间的单因素多重比较,筛选出叶片厚度、上表皮厚度和上表皮角质层厚度3项主要指标,并用隶属函数值法对8个品种的抗旱性大小排序为:园蓝>阳光蓝>梯芙蓝>灿烂>密斯黛>南月>布里吉塔>蓝鸟。     

苗期夜间低温对番茄叶片气孔开张度日变化及叶片超微结构的影响

以15℃夜温为对照,研究了6℃夜间低温对番茄叶片气孔开张度日变化及叶片结构的影响。结果表明:处理7d时,处理植株叶片气孔器大小和叶面积显著小于对照,气孔密度显著大于对照。表皮厚度极显著大于对照。叶片厚度大于对照,但与对照差异不显著。处理植株番茄叶片气孔张开程度一天中皆小于对照,气孔张开率上午与对照差异不显著,14:00显著小于对照。16:00极显著小于对照;恢复7d时,夜低温处理番茄叶片气孔器显著大于对照。气孔密度、每叶气孔数及单叶叶面积、气孔张开率皆小于对照,叶片气孔开口程度、叶片表皮厚度及厚度大于对照,但差异都不显著;夜间低温处理后叶片栅栏组织显得更紧密,恢复7d后无显著差异。     

不同品种紫斑牡丹叶片结构与抗寒性关系的初步研究

以气孔密度、表皮厚度、角质膜厚度和叶片组织结构紧密度等为观测指标,采用石蜡切片法和叶表皮离析法,对玫瑰红、玉瓣绣球和青春3个品种紫斑牡丹叶片解剖结构进行观察和对比分析,以探究不同品种紫斑牡丹与抗寒性的关系。结果表明:玫瑰红的抗寒性最强,玉瓣绣球次之,青春最弱。     

柱型苹果和矮生型梨组培苗叶片表皮结构研究

以柱型和普通型苹果各3个品种,矮生型和普通型梨各3个杂种实生苗的组培苗为试材,用扫描电镜观察其叶片表皮结构。结果表明,供试苹果和梨组培苗叶片上表皮细胞均为不规则的多边形,排列无方向性,上表皮无气孔分布。柱型和普通型苹果的上表皮细胞平均密度分别为2986个·mm-2和2087个·mm-2;矮生型和普通型梨的上表皮细胞平均密度分别为2633个·mm-2和1635个·mm-2。柱型苹果和矮生型梨的上表皮细胞密度分别显著高于其普通型。苹果和梨组培苗叶片下表皮气孔分布密集,气孔类型均为无规则型。柱型和普通型苹果的气孔平均长×宽分别为23.21μm×19.58μm和24.17μm×22.96μm,气孔密度平均分别为401.17个·mm-2和262.50个·mm-2;而矮生型和普通型梨气孔平均长×宽分别为29.57μm×20.30μm和26.93μm×24.51μm,气孔密度平均分别为265.67个·mm-2和158.00个·mm-2。柱型苹果、矮生型梨和其普通型之间的气孔长度差异不明显,而气孔宽度均显著小于其普通型,气孔密度均显著高于其普通型。     

草石蚕不同海拔叶表特征的比较研究

用过氧化氢-醋酸离析法对生长于不同海拔高度草石蚕的叶片表皮细胞形态、气孔特征进行了观察比较。结果表明:植物的叶表特征与其所处的环境密切相关。草石蚕表皮细胞形状,横切面观:上、下表皮细胞呈长方形;表面观:上表皮细胞呈多边形,而下表皮细胞形状不规则,其垂周壁浅波状;气孔形态随海拔上升呈现椭圆型—近圆形—椭圆型的转变,气孔器散生分布于下表皮细胞中,气孔取向无规则;气孔密度、气孔指数随海拔升高并不成线性关系。     

Impacts of water stress on gas exchange,water relations,chlorophyll content and leaf structure in the two main Tunisian olive (Olea europaea L.) cultivars

Leaf structural adaptations for the reduction of water loss were examined in two olive (Olea europaea L.) cultivars (Chemlali and Chétoui) growing under water stress conditions. Leaf measurements included leaf tissue thickness, stomatal density, trichome density, specific leaf area, leaf density, water relations, and gas exchange. We found considerable genotypic differences between the two cultivars. Chemlali exhibited more tolerance to water stress, with a thicker palisade parenchyma, and a higher stomatal and trichome density. Chemlali leaves also revealed lower specific leaf area and had higher density of foliar tissue and lower reduction in net CO₂ assimilation rate. The mechanisms employed by these two cultivars to cope with water deficit are discussed at the morpho-structural level. The morphological and structural characteristics of the leaves are in accordance with physiological observations and contribute to the interpretation of why the olive cv. Chemlali is more drought-tolerant than cv. Chetoui. Furthermore, from the behaviour of Chemlali plants we consider this cultivar very promising for cultivation in semi-arid areas.     

辣椒幼苗叶片解剖特征及光合特性对弱光的响应

 以弱光适应性不同的4个辣椒(Capsicum annuum L. )基因型（甜味型和辣味型）为试材，在人工气候室内研究了弱光（75~100 μmol·m^-2·s^-1）条件下辣椒幼苗叶片显微结构、叶绿体超微结构、气孔特征特性，以及光合特性的适应性变化。结果表明，弱光下辣椒幼苗叶片变薄，栅栏组织/海绵组织比值增加，'伏地尖'（辣味型）和'上海园椒'（甜味型）具有较高的栅栏组织/海绵组织比值；叶绿体数目减少，但叶绿体变大，基粒数、基粒厚度和基粒片层增加，淀粉粒增大、增多，2个辣味型材料比2个甜味型材料具有较高的叶绿体数和基粒数。辣椒（甜味型）展叶过程中下表皮气孔密度下降，而展叶14 d以后的气孔指数和单片叶气孔数变化不大。弱光下叶片气孔密度、气孔指数和单片叶气孔数减小，但气孔变大，其中'上海园椒'气孔纵轴、横轴较正常光照下增加，'20078'则横轴显著增加；弱光环境中叶片表皮细胞变大并发生扭曲皱褶，气孔与表皮平齐或略显外突，保卫细胞角质层上可观察到明显的环状褶皱。弱光下辣椒幼苗的光饱和CO₂同化速率(Asat)、暗呼吸速率(Rd)、夜间呼吸速率(R_n)、光呼吸速率(R_p)、光补偿点(LCP)、光饱和点(LSP)、CO₂补偿点(Г)、CO₂饱和点(CSP)、羧化效率(CE)以及RuBP最大再生速率下降，表观量子效率(Фi)上升；辣味型较甜味型材料Asat下降幅度较小，并且具有较低的LCP 、LSP 及其Rd 、Rn和Rp。弱光下各基因型辣椒的光合启动时间均有所延长，弱光敏感性材料表现更为明显。     

不同光质对水培脱毒马铃薯光合与结薯特性的影响

以红、蓝、红蓝(7︰1)、红蓝(5︰1)和白光5种光质LED灯作为光源,其中白光为对照,研究光质对水培脱毒马铃薯植株叶片发育、叶片光合性能、叶绿素荧光特性和结薯特性的影响。结果表明,在红蓝光(5︰1)处理条件下,水培马铃薯植株生长前期叶面积系数、叶绿素含量、气孔密度、气孔导度(Gs)均高于其他处理,P_n、Φ_(PSⅡ)、q_P、和ETR等显著高于白光处理,块茎形成和膨大最快。且定植60 d时叶绿素含量下降,P_n和PSⅡ活性中心开放程度显著下降,成熟期提前,微型薯产量和成薯率最高。在单色红光处理下,植株叶面积系数、叶绿素含量、G_s、P_n、F_v/F_o、Φ_(PSⅡ)和q_P下降,NPQ升高,块茎的形成和膨大缓慢,产量最低。在单色蓝光处理下前期叶片生长较快,块茎形成早,但不利于匍匐茎的形成,并引起叶片早衰,制约了块茎产量的提高。基于上述结果,光质调控前期可增加红光比例,诱导匍匐茎形成,后期增加蓝光比例,促进块茎形成和膨大,提高块茎的数量和产量。     

Effect of increasing climatic water deficit on some leaf and stomatal parameters of wild and cultivated almonds under Mediterranean conditions

The prevailing environmental conditions, temperature in particular, drive seasonal changes both in leaf development and stomatal characteristics. In order to ascertain the effect of increases in climatic water deficit on some leaf and stomatal parameters under field conditions, a study was carried out on two sets of leaves (spring and summer) on a large sample of Amygdalus communis L. cultivars in comparison with several Amygdalus webbii Spach seedlings, a species more adapted to arid environments and probable ancestor of cultivated almonds. Observations were performed between spring and summer of a particularly hot season. The results showed a significant and general reduction of both leaf area and stomatal frequency and an increase in stomatal size. Nevertheless, there were evident differences between cultivated and wild almonds. A stronger reduction of leaf area was observed in A. webbii (−31%) with respect to A. communis (−14%); on the contrary, the latter reduced stomatal frequency more than the former (−25% and −19%, respectively). The examined cultivated almonds, in response to the increase in climatic water deficit, tended to arrange their stomatal structures like those of wild almonds. Finally, increasing the climatic water deficit, the slope of the linear regressions between stomatal frequency and size did not change in either species, leading to a better understanding of the mechanisms of almond acclimation to environmental stresses.     

Air exchange rate affects the in vitro developed leaf cuticle of carnation

The leaf surfaces of Dianthus caryophyllus plants cultured in vitro in either airtight or ventilated vessels were examined using scanning electron microscopy (SEM). The resultant hyperhydrated, non-hyperhydrated and acclimatized plants were compared for stomatal density, cuticular wax development and stomatal function. The leaf surfaces of in vitro cultured plants were basically the same as those of acclimatized plants but less wax deposition was observed on their leaves. Stomata were found both open or closed after transfer of plants ex vitro. However, stomata of in vitro leaves grown in ventilated culture vessels were more functional than plants grown in other conditions. Acclimatized plants had a normal leaf epidermal surface, and were wholly covered with waxes; their stomatal density being similar to that of highly ventilated plants but lower than that of less ventilated plants. Leaves of plants grown in airtight culture vessels or under a low number of air exchanges per hour had less waxes than plants grown at a higher number of air exchanges per hour or than acclimatized plants. In contrast, hyperhydrated plants had abnormal, malformed stomata and no wax deposition was detected. The adaxial surface of non-hyperhydrated leaves seemed more normal than the abaxial, especially in the most ventilated vessels, and this may be due to the former receiving more light and so developing in a more favourable microenvironment.     

Effect of alleviating products with different mode of action on physiology and yield of olive under drought

Two years old self-rooted Koroneiki olive trees (Olea europaea L.) were subjected to two irrigation regimes, i.e. the fully irrigated and the severely water stressed trees, while they were treated with three alleviating products of different mode of action. The products used were the osmolyte glycine betaine, the antioxidant Ambiol and the heat and irradiance reflecting kaolin clay particles. The effects of product application and water regime on leaf characteristics, shoot and root growth, photosynthesis, leaf compatible solids (carbohydrates) concentration and yield were evaluated. All products applied, exhibited significant alleviating action, based on the relative alleviation index. Irrigated trees exhibited greater growth than drought stressed ones, while the ameliorating products maintained the water content of the leaves under drought conditions and resulted in lower leaf tissue density. On the other hand carbon assimilation rate, stomatal conductance and intrinsic water use efficiency were significantly reduced under drought stress, while the opposite stood for intercellular CO₂. Drought stress resulted in elevated sucrose leaf concentration, while the application of Ambiol increased stachyose concentration and that of glycine betaine did the same with the mannitol concentration. Among the alleviating products tested in this experiment Ambiol and glycine betaine had a significant positive effect on leaf water content, photosynthesis and yield under both drought and well irrigated conditions.     

Effects of water deficit on olive trees cv. Chemlali under field conditions in arid region in Tunisia

Water scarcity in the Mediterranean basin in addition to the extension of irrigated lands is one of the main factors limiting agricultural development. The need for supplementary irrigation of the Chemlali olive cultivar (Olea europaea L.) during summer and autumn periods was investigated. Leaf water content, gas exchange parameters, fruit development and yield in rain-fed and in irrigated plants have been monitored in 12-year-old olive trees grown under environmental conditions in semi arid regions characterized by high temperatures and high light intensity. Trees were subjected to three irrigation treatments, T0, T1 and T2 corresponding respectively to 0, 33 and 66% of crop evapotranspiration (ET_c) by a drip irrigation system. The water deficit during the summer (from June to August) led to the decrease of soil moisture, leaf water content and gas exchange parameters. Irrigated trees showed the same slow activity in the three summer months as the rain-fed trees. For all treatments, net CO₂ assimilation, stomatal conductance and transpiration rates were markedly decreased by environmental conditions (high air temperature and high light intensity) during the summer period. At the partial active growth phase of the Chemlali olive cultivar (September–November), a significant re-increase in all parameters was observed. However, net photosynthesis and stomatal conductance of control plants (T0) were, respectively, 57 and 40% lower than those of plants conducted under milder water contribution (T1). The decrease of physiological activity in irrigated plants during hot and dry (summer time) and cold (winter) seasons was a clear evidence that water supply during such periods will be without a great benefit for photosynthetic activity, and thus growth, if applied under critical conditions inducing the rest phase of the plant. The non-statistically significant slight differences as well in photosynthetic performances activities (Pn, Gs and E rates), as in olive production between the two irrigated treatments will not cover the expenses of water loss when applying irrigation at 66% of ET_c especially in arid region characterized by scant and irregular rainfall. On the light of these results, we can conclude that the irrigation of this species during the vegetative growth phase (in spring and autumn), and stopping it during the olive rest phase (in summer and winter) could be recommended at least under the experimental conditions of this study; and that the contribution of 600 mm of water per year (33% of ET_c) can respond to the needs of the Chemlali olive cultivar in a semi arid region without impairing photosynthetic activity and olive production.     

Variation in baobab seedling morphology and its implications for selecting superior planting material

With the aim of helping to select superior planting material for drought characteristics, baobab seedlings from two countries, one in western and one in south-eastern Africa, were grown in a greenhouse and their growth and morphology were studied. Seedlings were grown for 18 weeks and several morphological characteristics (length, diameter and dry weights of different plant parts, number of leaves, stomatal density, among others) were recorded at different harvesting times. Biomass allocation changed with time: seedlings invested more in fine roots and leaves in the beginning of their growth while later they invested more in the development of the taproot. In general, at any harvest time, seedlings from Malawi were larger; but seedlings from Mali had higher relative growth rates and a faster ontogeny. Seedlings from Mali had shorter hypocotyls, their stems were thicker, they had fewer leaves, lower leaf area ratios and, in general, they had a higher stomatal density than those from Malawi. Significant differences between provenances within one country could also be observed. In general, seedlings from drier provenances were smaller overall, they had fewer leaves, higher taproot water content and stomatal density, characteristics often related to drought adaptation. Seedlings from drier provenances also invested more in their taproot, a key organ for baobab seedling survival. Although our seedlings were only grown under optimal conditions in a greenhouse, results from this study indicate that there is a great variation in baobab seedling growth, biomass allocation to plant parts and morphology, which gives opportunities to select high quality planting material.