大血藤叶的生长及光合生理生态特性研究

对大血藤叶的生长及光合生理生态特性进行了研究,结果表明:大血藤叶的长度、面积和干重的增加有共同的趋势,即在叶的生长早期增长很快,以后逐渐降低,叶长度、面积约在7月中旬达到最大值,叶干重8月初达到最大值。随着叶的生长,叶绿素含量、硝酸还原酶活力逐渐增加,至8月达到最大值,以后逐渐下降。春、夏期间的光补偿点低于秋季,而光饱和点则高于秋季。叶的光合日进程在春季呈"单峰"曲线;在夏、秋季则呈"双峰"型,有明显的"午休"现象。日均净光合速率在整个生长季节的变化是随着叶的生长,先是上升,至8月初达到最大值,然后逐渐下降。夏季,大血藤日均净光合速率比常绿阔叶树种低,比落叶阔叶树种高。     

提前钩梢对雷竹地上构件生物量分配及其异速生长的影响

为摸清提前钩梢对雷竹地上构件生物量积累与分配及其异速生长模式的影响,为雷竹林合理钩梢提供参考,调查了5月(提前钩梢)、6月(常规时间钩梢)钩梢和未钩梢雷竹林新竹当年(1年生立竹)和第2年(2年生立竹)秆、枝、叶生物量,分析了立竹地上构件生物量积累与分配特征及其异速生长。结果表明:钩梢使雷竹1年生立竹秆、枝、叶生物量显著下降,秆生物量分配比例显著升高,枝、叶生物量分配比例显著下降,枝、叶-总生物量异速生长指数显著增大,秆-总生物量异速生长指数显著减小,且常规时间钩梢立竹叶生物量及其分配比例和出叶强度均显著高于提前钩梢立竹。钩梢也导致雷竹2年生立竹秆、枝、叶生物量明显下降,但秆、枝、叶-总生物量异速生长指数均显著增大,常规时间钩梢立竹叶生物量仅略低于未钩梢立竹,且叶生物量分配比例及出叶强度均显著高于未钩梢和提前钩梢立竹。研究表明提前钩梢对雷竹叶生物量及其分配比例、出叶强度及异速生长均有明显的负面影响,不利于雷竹林光合能力的发挥,因此,雷竹林不宜提前钩梢。     

玉米幼苗叶片生长部位和瞬时生长速率的测定

研究植物生长不但需要知道生长的部位,更需测定其生长速率。过去曾用“等距线条或方格”、“水平显微镜”、“生长自动记录仪”以及直接度量生长器官等方法,测定植物生长部位和生长速率。本文介绍另一种测定玉米等单子叶植物叶片生长部位及生长速率的方法。 1.叶片生长部位的测定单子叶植物     

温度和淹水深度对水稻幼苗生长的影响

(1)银坊品种水稻的幼苗,在本实验的条件下以25℃(本实验所用最高温度)和不淹水时生长良好,10℃以下生长即受到阻礙,除胚芽鞘稍能生长外,根、叶不能正常生长。 (2)胚芽鞘在低温舆淹水时比根、叶生长较快,根、叶在高温不淹水时相对的比胚芽鞘生长的好。并且,根最不能忍耐水层。因此,稻苗不同器官对温度的要求由高到低依次是叶>根>胚芽鞘。而对水层的忍耐能力由大到小依次是胚芽鞘>叶>根。 (3)整株稻苗淹水时对稻苗的危害性最大。淹水可能使稻苗生长所利用的物质转变为能量的效率减低,消耗胚乳的物质较多而新叶及侧根的出现速度减慢成为柔弱的稻苗。 (4)在水稻幼苗生长时期,旱育苗比水育苗生长良好,主要是增加了氧的供应条件。 (5)本实验的结果指出了,水稻幼苗的不同器官对外界环境的要求是不一样的。在淹水的条件下,胚芽鞘比根、叶生长的好,而在通气良好的条件下,根则较胚芽鞘和叶生长的好,在较低的温度下根比叶相对的生长的好。     

密度对尖头叶藜生物量分配格局及异速生长的影响

植物器官指示植物不同的功能,而植物器官生物量分配比例的变化表征了植物对资源获取能力的调整。在植物生长发育过程中,植物各器官呈一种明显的异速生长规律。利用异速生长分析方法,通过模拟不同密度(16、44.4、100、400株/m~2)下尖头叶藜(Chenopodium acuminatum)的生长特性,研究密度对尖头叶藜器官生物量分配格局及异速生长的影响。结果表明,随密度增加,尖头叶藜地上和地下器官都存在不同程度的竞争:其中,根和主茎生物量分配增加,茎和地上生物量分配减少,而叶和繁殖生物量分配不随密度变化而变化。研究发现,尖头叶藜各器官间具有显著的异速生长关系:其中叶∶主茎、根∶地上部分、根∶茎、根∶主茎、繁殖器官∶地上部分及繁殖器官∶根生物量间的异速生长不随密度变化而变化,属于表观可塑性;而叶∶地上部分、叶∶根、叶∶茎、茎∶地上部分、主茎∶地上部分、繁殖器官∶茎、繁殖器官∶主茎生物量间具有极显著的异速生长关系,异速指数和个体大小显著受密度变化影响,属于真正可塑性,这表明密度能够影响尖头叶藜各器官的生长变化。尖头叶藜叶∶主茎、叶∶根及主茎∶地上部分生物量间的异速指数在D4-密度时与3/4差异不显著(P0.05),符合生态代谢理论,而在D1—D3密度时与3/4差异显著(P0.05),表明充分竞争的植株更符合代谢理论,而竞争不激烈的植株对资源的投入具有物种特异性。     

高粱不同器官生长对NaCl胁迫的响应及其耐盐阈值

用砂基培养研究高粱不同器官生长对NaCl胁迫的响应及其耐盐阈值。NaCl胁迫下,独角虎和糖高粱均表现为生长叶叶鞘鲜重下降最大,其次是生长叶叶片、成熟叶叶鞘和叶片变化最小。长期胁迫单株叶片数及叶面积也明显下降。相同胁迫情况下,糖高梁的生长抑制明显大于独角虎。独角虎和糖高粱耐盐阈值分别为135和82mmol／LNaCI。以上结果表明独角虎耐盐能力明显大于糖高粱。讨论了不同器官生长抑制的机制。     

宽叶缬草繁殖生物学特性研究

报道了药用植物宽叶缬草自然生长的历程,并对其不同生长环境及传粉环境下收获的瘦果千粒重和发芽率进行了统计分析。结果表明在不同的生长环境中,宽叶缬草瘦果千粒重有极显著差异;而在不同传粉环境中,养蜂实验区和防蜂实验区瘦果的发芽率有极显著差异,且前者高出后者近4倍。证明了通过增加传粉媒介蜜蜂的数量能够解决宽叶缬草人工栽培中的制种问题,从而使大面积栽培宽叶缬草成为可能,实现对宽叶缬草资源的可持续利用。     

沙地云杉苗期生长与干物质生产关系的研究

本文用不同_的模型定量地研究了沙地云杉苗期的生长规律、季节动态及不同生长时期干物质在各器官之间的分配规律。1)1年生幼苗一直保持较高的生长速度,根生长尤为迅速。5年生幼苗在接近生长上限时,增长越来越慢。2)根、茎、叶干物质的生产符合理查德模型;根、茎、叶干重与全株干重之百分比表现出不同的变化趋势,反映了于物质在各器官中的分配规律。3)不同年度各器官的干重变化反映了由于自疏造成的叶的脱落和部分枝的脱落情况。4)各模型的相关系数几乎都达到了极显著的水平。     

耳叶马兜铃引种试验初报

本文介绍了药用植物耳叶马兜铃在桂林引种试验的初步结果。文章对耳叶马兜铃引种试验的材料与方法、试验内容与结果、生长特性及产量以及病虫害的防治,分别作了阐述。     

高梁不同器官生长对NaCl胁迫的应用及其耐盐阈值

用砂基培养研究高梁不同器官生长对ＮａＣｌ胁迫的响应及其耐卤阈值。ＮａＣｌ胁迫下,独角虎和糖高梁均表现为生长叶叶鞘鲜重下降最大,其次是生长叶叶片、成熟叶叶鞘和叶片变化最小。长期胁迫单株叶片数及叶面积也明显下降。相同胁迫情况下,糖高梁的生长抑制明显大于独角虎。独角虎和糖高梁而盐阈值分别为１３５和８２ｍｍｏｌ／Ｌ ＮａＣｌ。以上结果表明独角虎耐卤能力明显大于糖高梁。讨论了不同器官生长抑制的机制。     

缺锰降低大豆叶片叶绿素荧光的高能态猝灭

缺锰大豆叶片光合速率比对照低 5 0 %左右。缺锰叶片的Fv/Fm较对照低约 30 %～ 40 % ,而Fo比对照高 2～ 3倍左右。强光下 ,缺锰叶片的qP为对照的5 0 %。缺锰降低了叶片的高能态猝灭 (qE) ,仅占其NPQ的 6 0 %左右 ;而对照 qE组分占NPQ的 90 %左右。对照和缺锰叶片叶黄素库的脱环氧化程度分别为36 %和 2 1%左右。认为缺锰叶片 qE的降低可能是由于叶黄素脱环氧化程度减少所致     

金叶马褂木叶片特性及其 RAPD 分子鉴定

金叶马褂木是从当地金边马褂木中发现的春季至初夏间全叶呈金黄色至淡黄色的芽变材料。对该芽变种质的叶片特性进行了连续8年的观察与调查,同时结合RAPD技术进行了初步的分子鉴定。叶片特性观察与调查结果表明,金叶马褂木叶片大小与金边马褂木、北美马褂木差异不大,但叶片叶绿素含量显著少于金边马褂木和北美马褂木,叶片色泽也与金边马褂木有显著性差异。结合RAPD分子鉴定结果,认为金叶马褂木是一个发生变异的新种质。     

适应不同光环境小蜡叶片气孔导度、气孔开度和气孔密度的时空变化

对生长在强光环境和弱光环境小蜡叶片的气孔参数测定发现 :气孔导度和气孔开度在 4个取样部位存在异质性分布。气孔导度和气孔开度经回归分析呈线性、指数或多项式分布。统计分析表明 :强光下的叶片气孔导度和气孔开度的相关性明显高于弱光环境叶片的数值。无论强光环境还是弱光环境下的叶片 ,在取样部位编号为1和 3,其气孔导度和气孔开度均存在显著的线性关系。弱光环境下叶片的气孔密度要远低于强光环境下的叶片。强光环境下叶片对变化环境的敏感性要大于弱光环境下的叶片 ,这可能与强光环境叶片具有较高的气孔密度有关。     

菊花黄绿叶突变体不同类型叶片的叶绿素含量和结构特征比较

以菊花黄绿叶突变体-NAu04-1-31为试验材料,测定了黄叶、黄绿叶和绿叶3种不同类型叶片的叶绿素含量,并观察比较了叶片的显微与超微解剖结构.叶绿素含量测定表明:黄叶、黄绿叶的叶绿素含量显著低于绿叶,而黄叶叶绿素a与叶绿素b的比值大于绿叶.叶绿体显微与超微结构观察发现:黄叶细胞内叶绿体形状不规1则,缺乏正常的叶绿体膜结构,无类囊体,无淀粉粒,嗜锇颗粒较多;黄绿叶叶片栅栏组织绿色部分与绿叶的栅栏组织相似,黄色部分与黄叶的栅栏组织棚似,黄色部分的海绵组织中有类似于绿色叶片的海绵组织结构,而绿色部分含有类似于黄叶的海绵组织的结构特征.绿叶细胞内叶绿体较多,形状规则,基粒片层清晰,其内淀粉粒多而大,嗜锇颗粒较少.     

适应不同光环境小蜡叶片气孔导度、气孔开度和气孔密度的时空变化

对生长在强光环境和弱光环境小蜡叶片的气孔参数测定发现:气孔导度和气孔开度在4个取样部位存在异质性分布.气孔导度和气孔开度经回归分析呈线性、指数或多项式分布.统计分析表明:强光下的叶片气孔导度和气孔开度的相关性明显高于弱光环境叶片的数值.无论强光环境还是弱光环境下的叶片,在取样部位编号为1和3,其气孔导度和气孔开度均存在显著的线性关系.弱光环境下叶片的气孔密度要远低于强光环境下的叶片.强光环境下叶片对变化环境的敏感性要大于弱光环境下的叶片,这可能与强光环境叶片具有较高的气孔密度有关.     

Nitrogen resorption and photosynthetic activity over leaf life span in an evergreen shrub, Rhododendron ferrugineum, in a subalpine environment

Here, the advantages for a shrub of having long vs short-lived leaves was investigated in Rhododendron ferrugineum by following nitrogen(15N) and carbon(14C) resorption and translocation, and photosynthetic capacity over the life span. Mean leaf life span was 19 months. Nitrogen (N) resorption in attached leaves occurred mainly in the first year (23%) and reached a maximum of 31% in the second. Although, resorption was similar in attached and fallen 1-yr-old leaves, it was on average one-third higher in fallen than in attached older leaves. Final N resorption of a leaf compartment reached 41%, half occurring from healthy leaves during the first year. Photosynthetic capacity decreased slightly during the life span. Before shoot growth, plant photosynthesis was mainly supported by 1-yr-old leaves, although the contribution of the 2-yr-old leaves was nonnegligible (15% of the capacity and higher carbon transfer toward the roots). After shoot growth, the current-year leaves made the greatest contribution. Our results suggest that short-lived leaves (half of the cohort) are mainly involved in a photosynthetic function, having a high photosynthetic capacity and drawing most of their resorbed N towards current-year leaves; and long-lived leaves are also involved in a conservative function, increasing N resorption and mean residence time (MRT).     

ABA and polyamines act independently in primary leaves of cold-stressed tomato (Lycopersicon esculentum)

The effects of ABA and putrescine, a polyamine, on cold-induced membrane leakage were investigated using primary leaves of wild-type and an ABA-deficient mutant, flacca , of tomato ( Lycopersicon esculentum Mill.). The amount of chilling-induced electrolyte leakage from flacca leaves was much higher than that from the wild-type leaves. When applied exogenously ABA reduced cold-induced electrolyte leakage from leaves of both wild-type and the flacca mutant. However, the cold-induced electrolyte leakage from flacca leaves was not as pronounced as in the wild-type indicating that ABA is an important mediator in response to cold stress in the leaves. Putrescine reduced cold-induced electrolyte leakage from both wild-type and flacca leaves. Synthesis of putrescine in the leaves was increased by cold treatment. DFMO, a biosynthetic inhibitor of the polyamine, increased electrolyte leakage from cold-treated leaves, and exogenously applied putrescine decreased the enhanced leakage to the control level. Therefore, this polyamine is thought also to be involved in the response to cold stress of tomato leaves. Both ABA and putrescine were protective against cold stress, but exogenously applied ABA decreased the endogenous level of putrescine in the leaves. Furthermore, the DMFO-increased electrolyte leakage in cold-stressed leaves was completely abolished by the application of ABA. These results suggest that ABA is a major regulator in the response to cold stress in tomato leaves and that it does not exert its role via putrescine in the response to cold stress.     

Leaf developmental stage affects sulfate depletion and specific sulfate transporter expression during sulfur deprivation in Brassica napus L

BRASSICA NAPUS was grown under hydroponic conditions and responses to the removal of the external supply of sulfur (S) were analysed in roots and in leaves of different developmental age. The concentrations of sulfate and nitrate were greatest in the older leaves and least in younger leaves, whilst phosphate was greatest in roots and youngest leaves and least in old leaves. S-deprivation resulted in decreases in tissue sulfate concentrations at variable rates in the order: roots and young leaves > middle-aged leaves > oldest leaves. Phosphate concentrations were unaffected and nitrate concentrations were only depleted in the oldest leaves. Expression of representative members of the sulfate transporter gene family was assessed by Northern blotting in the respective tissues. Group 1 transporters (high affinity type) were induced in response to S-deprivation in all tissues except old leaves, where no expression was detected, and to the greatest extent in roots. Groups 2 and 5 (a BRASSICA Group 5 sulfate transporter is reported here, accession number: AJ311389) transporters showed either no or only a small induction by S-deprivation. Group 4 transporters (localised in the tonoplast membrane and thought to be involved in vacuolar sulfate efflux) were induced by S-deprivation with a complex pattern: 4;1 was expressed in root and mature leaves, was strongly induced by sulfur-deprivation in roots, and was also induced in the middle-aged leaves alone; 4;2 was only expressed under S-deprivation in parallel with the observed pattern of tissue sulfate concentrations. Expression patterns indicated that both differences in intracellular sulfate pools and localised aspects of the signal transduction pathway link tissue sulfate-status and sulfur-nutrition regulated gene expression.     

Senescence of rice leaves XXXI. Changes of chlorophyll,protein, and polyamine contents and ethylene production during senescence of a chlorophyll-deficient mutant

Leaf senescence of a chlorophylldeficient rice mutant (LT-8) was investigated. At 10 days after planting, the chlorophyll level in the third leaves of rice seedlings of the mutant was about one half that of normal leaves (Norin no. 8), whereas no difference in the protein level could be detected in the two genotypes. The protein level in leaves decreased with increasing age, and no significant difference could be detected during senescence in the two genotypes. Chlorophyll level in the normal leaves also decreased with increasing age. However, the chlorophyll level in the mutant leaves began to decrease only after more than 60% of the initial protein had been degraded. The pattern of ethylene production in the normal leaves was, in general, similar to that in the mutant leaves. Ethylene production first decreased with age, increased to a maximum at day 18, and decreased thereafter. Both spermidine and spermine levels in the leaves of the two genotypes decreased with increasing age. The pattern of the putrescine level in the normal leaves behaved somewhat similar to that in the mutant leaves. However, during the course of senescence, the putrescine level in the mutant leaves was always higher than that in the normal leaves. The possible relationship between endogenous polyamine levels and ethylene production is discussed.