果实裂果影响因子研究进展

裂果是一类生理性病害,果实开裂后既影响外观,又容易受到病菌的侵染出现浆烂果,果实商品价值严重降低并造成重大经济损失。笔者从果实的表型特征、遗传因素、生理特性、矿质元素、环境、植物生长调节剂、栽培措施等方面对裂果的影响因子进行了分析,并就今后研究的方向进行了讨论。     

土壤调盐改良对咸水灌溉冬小麦光合和蒸腾的影响

在天津滨海地区高水位、黏重土壤利用田间小区试验研究土壤调盐改良技术对咸水灌溉的冬小麦光合速率、蒸腾速率、气孔导度、叶绿素含量指数等生理指标的影响,试验结果表明,冬小麦播种前采用适当土壤调盐改良技术能够提高冬小麦抽穗期、灌浆期的光合速率、叶绿素含量指数,降低气孔导度、蒸腾速率.小麦冬前施用75 kg/100 m2改良剂(40％风化褐煤+40％磷石膏+20％脱硫石膏)有利于提高冬小麦灌浆期的光合速率,有降低抽穗期、灌浆期小麦的蒸腾速率的效果,冬前施用45 kg/100 m2改良剂(20％风化褐煤+40％磷石膏+20％脱硫石膏+20％沸石粉)对提高冬小麦抽穗期光合速率有利,同时也提高抽穗期小麦的蒸腾速率;土壤调盐改良剂对咸水灌溉冬小麦的气孔导度有明显抑制作用,冬前施用30kg/100 m2改良剂(40％磷石膏+20％脱硫石膏+40％沸石粉)的冬小麦气孔导度与不采用改良措施相比,抽穗期降低52.28％,灌浆期降低39.51％;冬前施用45 kg/100 m2或75 kg/100 m2改良剂(40％风化褐煤+40％磷石膏+20％脱硫石膏)和30 kg/100 m2改良剂(40％磷石膏+20％脱硫石膏+40％沸石粉)均能够显著提高抽穗、灌浆期冬小麦的叶绿素含量指数;冬前施用45 kg/100m2改良剂(20％风化褐煤+40％磷石膏+20％脱硫石膏+20％沸石粉)和30 kg/100 m2改良剂(40％磷石膏+20％脱硫石膏+40％沸石粉),即使在较高土壤含盐量也能够使冬小麦光合速率保持在较高水平,使冬小麦蒸腾速率受到土壤含盐量影响不明显.     

Compensatory Growth Responses During Reproductive Phase of Cowpea after Relief of Water Stress

Unpredictable drought affects growth and yield of dryland cowpea ( Vigna unguiculata [L.] Walp.) during rainy season. With the objective of identifying compensatory growth responses after relief of water stress, pot-grown plants (cv. C-752) were water-stressed at flowering, and physiological responses, short term dry matter partitioning upon relief of water stress, and productivity at maturity were studied. Water stress decreased, to varying degrees, leaf water potential, stomatal conductance, photosynthesis rate and transpiration rate. Recovery in assimilation lagged behind that in water relations. Assimilate supply seemed to be limiting early pod growth upon relief of water stress due to low photosynthesis rate, reduced leaf area per pod, and increased partitioning to leaf expansion. However, later pod growth was not limited by assimilate supply and final dry matter per pod was similar in both non-stressed and stress-affected plant. Cowpea exhibited the following growth responses during pod-fill stage upon relief of water stress: 1. increase in leaf area, 2. shift in dry matter partitioning in favour of leaf expansion, 3. extended green leaf duration, and 4. increase in pod number. These partially compensating physiological responses probably ensure reasonable productivity of dryland cowpea during rainy season.     

Photosynthetic acclimation of shade-grown red pine (Pinus resinosa Ait.) seedlings to a high light environment

Photosynthetic light acclimation in red pine (Pinus resinosa Ait.) seedlings was examined in a greenhouse study to better understand the physiological response of this species to increased light intensity following release from competition. Seedlings grown in a high (HL), medium (ML) or low (LL) light environment for 12 weeks were transferred to high light. Gas exchange and chlorophyll fluorescence of ML and LL seedlings were measured prior to and following transfer and compared with the HL control treatment. Photosynthetic characteristics were related to initial light treatment and time after transfer. Acclimation of gas exchange features to high light in shade formed ML and LL foliage was relatively rapid, with similar values among light treatments within 57 days of transfer. Acclimation of net photosynthetic rate was similar in ML and LL seedlings, and was associated primarily with increased mesophyll conductance to CO₂. The ratio of variable to maximal chlorophyll fluorescence (F_v/F_m) decreased initially after transfer, especially in LL seedlings, but recovered to normal values after 57 days. Red pine seedlings appear to be well adapted for photosynthetic acclimation to high light intensity, consistent with that reported for other early successional tree species.     

Influence of irrigation regimes on growth and yield of potato cv. Spunta

Summary The effect of furrow and drip irrigation giving 0, 33, 66, 100 and 133% of the maximum evapotranspiration (ETM) was studied on leaf transpiration, stomatal resistance, tuber growth, yield and yield response of cv. Spunta. The research was carried out in Sicily in 1988 and 1989 on early potato crops grown during the winter/spring cycle. Increased water supply increased leaf transpiration, plant fresh weight, tuber growth rate, yield and earliness, and decreased stomatal resistance and tuber dry weight. A higher yield response was obtained at the lower water regimes (ETM of 33 and 66%). There were no significant differences between the two methods of irrigation.     

蝴蝶兰倍性与叶部和花部性状的相关性

【目的】研究蝴蝶兰Phalaenopsis倍性与主要性状的相关性.【方法】采用压片法对85份蝴蝶兰资源的倍性进行了鉴定,测量了这些资源的气孔长度、气孔密度、叶长、叶宽、叶厚、花朵直径和花朵数.【结果和结论】85份蝴蝶兰资源中3份为二倍体,占3.5%;9份为三倍体,占10.6%;73份为四倍体,占85.9%.四倍体蝴蝶兰的气孔长度和花朵直径显著大于二倍体和三倍体,而气孔密度和花朵数显著少于二倍体和三倍体(P0.05).三倍体蝴蝶兰的气孔长度、花朵直径和花朵数与二倍体蝴蝶兰差异均不显著(P0.05),但气孔密度显著小于二倍体(P0.05).四倍体蝴蝶兰的叶长显著大于二倍体(P0.05),但二倍体与三倍体、三倍体与四倍体在叶长上差异不显著(P0.05).二倍体、三倍体和四倍体在叶宽和叶厚上差异均不显著(P0.05).蝴蝶兰倍性与气孔长度、叶长和花朵直径呈极显著的正相关关系,与气孔密度和花朵数呈极显著的负相关关系.     

不同土壤条件对番茄叶片气孔导度的影响

以番茄为试验材料,研究有机土壤与普通土壤培养条件下番茄叶片气孔导度的变化.结果表明,有机土壤条件下的番茄气孔长度与气孔宽度均高于无机土壤,但有机土壤条件下番茄叶片的气孔密度低于无机土壤条件.     

十个芍药品种气孔特性研究

选取10个品种的芍药作为研究对象,观察芍药叶片气孔的形态、分布规律,并对其气孔大小、气孔长宽比、表皮细胞密度、气孔密度及气孔指数等进行品种间比较及差异分析.结果表明:10个品种的芍药叶片气孔形态及分布规律一致.各项指标的品种内变异系数均较小.4个品种(1、2、8、9)的4项指标(气孔长度、宽度、长宽比及气孔指数)均没有差异.2个品种(1、9)的5项指标(气孔长度、宽度、长宽比、气孔密度及气孔指数)均没有差异.各项指标相比较,气孔宽度和气孔指数在各品种间变化较小.气孔密度与气孔长度呈反相关.结果不支持将气孔长度、宽度、气孔长宽比、气孔密度、气孔指数及表皮细胞密度作为芍药种或品种分类的依据.     

Stomatal and Non-stomatal Effects of Salinity on Photosynthesis in Faba Beans (Vicia faba L.)

The effect of salinity (40 and 80 meq/1 NaCl) on stomatal conductance, chlorophyll content, ultrastructural damage and photosynthetic performance of six cultivars of faba beans ( Vicia faba L.) from different agroclimatic regions were investigated. Low levels of salinity (40 meq/1 NaCl) increased chlorophyll content in some cultivars but did not lead to simultaneous increase in photosynthesis (P). Increased salinity levels (80 meq/1 NaCl) decreased chlorophyll content and stomatal conductance. Ultrastructural damage was observed in sensitive cultivars even at low salinity levels. Based on the parameters investigated, there was no concrete evidence to suggest that the physiological processes of cultivars from arid and semi-arid regions are less affected under saline conditions as compared to cultivars from temperate regions. The results suggested increased salinity affects P not only due to its effect on stomatal closure but also due to other non-stomatal effects like ultrastructural damage and decrease in chlorophyll content below a threshold level.     

Physiological responses of Populus euphratica Oliv. to groundwater table variations in the lower reaches of Heihe River, Northwest China

Riparian vegetation in the lower reaches of Heihe River serves important ecological functions. However, the riparian ecosystems have been constantly deteriorating in the past 30 years simply due to water interception for oasis agricultural irrigation in the middle reaches of the river. This study pays a particular attention to Populus euphratica Oliv. forest because it is a dominant component of the riparian ecosystem in the lower reaches of Heihe River where the depth of groundwater table is the controlling factor in sustaining riparian ecosystems. To reveal leaf-related physiological responses of Populus euphratica Oliv. forest to groundwater table variations, we analyzed the relationships between the depth of groundwater table (DG) and three leaf-related parameters, i.e. leaf stomatal density (SD), specific leaf area (SLA), and stable carbon isotopic composition (δ 13 C). Our results show that the relationship between DG and leaf SD is a bi-mode one shaped by both salt stress and water stress. That is, salt stress appeared in shallow groundwater conditions and water stress happened in deep groundwater conditions, and the thin layer around 2.7 m of DG is a stress-free layer. Leaf SD fluctuated according to the DG variation, first decreased with increasing DG, then increased at depths ranging 2.7-3.7 m, and after a relatively stable plateau of SD at depths ranging 3.7-5.2 m, decreased again with increasing DG. Our results also show that SLA decreased exponentially with increasing DG and foliar δ 13 C values are also strongly dependent on DG, further demonstrating that these two parameters are sensitive indicators of water stress. The exponential curve suggests that SLA is more sensitive to DG when groundwater table is shallow and 3 m seems to be a threshold beyond which SLA becomes less sensitive to DG. Foliar δ 13 C becomes more sensitive when the groundwater table is deep and 7 m seems to be a threshold below which the δ 13 C signature becomes more sensitive to DG. These findings should be helpful in monitoring the growth and development of Populus euphratica Oliv. forests and also in providing protection measures (i.e. DG related) for Heihe River riparian forests.