Growth, stomata aperture, biochemical changes and branch anatomy in mango (Mangifera indica) cv. Chokanan in response to root restriction and water stress

Mango production is often subject to space and tree size management pressures among growers. This study found that root restriction contributed to reduced leaf expansion, thus inhibiting the growth of mango trees. There was even less leaf expansion under water stress conditions. Under well-watered conditions, restricted roots considerably reduced stomatal conductance and leaf water potential compared to control root growth. More rapid reductions in stomatal conductance and leaf water potential occurred under restricted root and water stress conditions compared to control trees. Leaf proline concentrations and abscisic acid (ABA) levels increased as a result of root restriction and water stress but decreased with re-watering. Re-watering also increased stomatal conductance, leaf water potential and peroxidase accumulation in plants with both restricted and non-restricted root growth. Anatomical studies of cross sections of secondary branches showed that root restriction and water stress brought about various changes: compacted cells, as estimated by epidermis thickness and area, as well as by cortex thickness, but with increases in schelerenchyma thickness, phloem and xylem thickness, schelerenchyma area, and pith area and diameter. These results suggest that reduction of soil volume and water stress could effectively control tree size through physiological and morphological changes; thereby bringing higher sustainable returns per hectare and greater effectiveness in orchard management.     

外源甜菜碱对盐胁迫下加工番茄生理特性的影响

研究了外源甜菜碱对加工番茄幼苗抗盐性的影响。结果表明:外源甜菜碱可以显著提高加工番茄叶片中脯氨酸和可溶性糖含量,可以提高加工番茄叶片SOD活性,降低膜透性和MDA的含量,从而有效的提高加工番茄的抗盐性。在该试验中叶面喷施高浓度的甜菜碱比低浓度的甜菜碱效果更明显。     

山西部分梨品种抗寒性测定及生理指标研究

通过鉴定山西部分梨品种的抗寒性以达到对抗寒育种中亲本的选择。以1 年生梨枝条为试材,在人工低温处理下研究7 个梨品种枝条中相对电导率、可溶性糖、可溶性蛋白、脯氨酸和束缚水含量的变化规律,并分析各生理指标之间的相关性。结果表明：（1）供试梨品种的抗寒性顺序为：‘苹果梨’>‘晋酥梨’>‘晋蜜梨’>‘玉露香梨’>‘雪花梨’>‘玉酥梨’>‘库尔勒香梨’。（2）相对电导率、可溶性糖、脯氨酸和可溶性蛋白含量随处理温度的下降而上升。（3）可溶性糖含量与抗寒性呈显著正相关,而脯氨酸和可溶性蛋白含量与抗寒性无明显相关性。综合以上研究结果,在低温胁迫条件下,可溶性糖可单独作为抗寒性的鉴定指标。鉴定指标。     

脯氨酸代谢途径在调控水稻phyB突变体干旱胁迫耐性中的作用

本研究分析了水稻野生型和phyB突变体中脯氨酸代谢途径关键基因的表达水平。结果显示,干旱处理能够诱导脯氨酸生物合成相关基因OsP5CS1和OsOAT的表达,抑制脯氨酸生物降解基因OsP5CDH的表达。且phyB突变体中OsP5CS1基因的表达水平明显高于野生型,据此推测phyB负调控OsP5CS1基因的表达。为了分析OsP5CS1基因的高水平表达是否与phyB突变体较强的干旱胁迫耐性有关,本研究进一步培育了转OsP5CS1基因烟草。离体叶片失水速率结果表明,转基因烟草的失水速率小于野生型;盐胁迫条件下,转基因烟草的分化率明显高于野生型。综上所述,phyB对脯氨酸代谢途径的调控是phyB突变体具有较强干旱胁迫耐性的重要因素之一。     

4种内吸性杀虫剂对番茄幼苗生长的影响

为明确吡蚜酮、吡虫啉、螺虫乙酯和溴氰虫酰胺4种内吸性杀虫剂对番茄幼苗生长的影响及生理生化响应.以'粉印三号'为供试植株,测定4种杀虫剂不同浓度处理8片真叶期植株15 d后植株株高、茎粗、主根长、根系活跃吸收面积、叶绿素、3种抗氧化保护酶[超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)]和游离脯氨酸...     

低温胁迫下两品种羽衣甘蓝叶中渗透物质含量比较

以2个羽衣甘蓝品种为材料,研究了低温胁迫下其叶片中渗透物质的含量,初步探究2种羽衣甘蓝的耐寒性。结果表明,低温胁迫下,2种羽衣甘蓝叶片中可溶性糖含量皆在11.3%左右,差异不显著。与奶白色品种相比,紫红羽衣甘蓝叶片中脯氨酸和可溶性蛋白含量较高,分别为0.448%和0.566%,且差异显著。另外,紫红色品种中叶片各色素含量皆高于奶白色品种。由此证明,紫色品种羽衣甘蓝比白色品种羽衣甘蓝有较强的抗寒性。     

Tissue distribution of glycinebetaine,proline and inorganic ions in barley at different times during the plant growth cycle.

The study of tissue distribution of glycinebetaine in barley grown hypoponically revealed that, during the vegetative growth period, young actively growing leaves accumulated higher levels than the mature lower leaves. Proline showed a complex pattern of leaf distribution. While K⁺ and Cl^‐ were uniformly distributed, the former being at a much higher concentration, levels of Na⁺ Ca²⁺ and Mg²⁺ were generally higher in the older leaves than the younger leaves. As the plants matured their leaves contained higher levels of divalent cations. The ear contents of glycinebetaine, proline, Ca²⁺ and Mg²⁺ increased with the ear maturity. The relative contribution of cations to the tissue osmotic pressure is discussed.     

Physio-Biochemical Responses of Oil Palm (Elaeis guineensis Jacq.) Seedlings to Mannitol- and Polyethylene Glycol-Induced Iso-Osmotic Stresses

References

The aim of this investigation was to comparatively examine the physio-biochemical responses of oil palm seedlings to mannitol- and PEG-induced iso-osmotic stresses. The water content of osmotically stressed oil palm seedlings decreased, but the proline content and the electrolyte leakage of the seedlings increased with decreasing water potential (Ψ_w). However, the responses varied with the strength of osmotic stress and type of osmotic agent. Relative electrolyte leakage (REL) was negatively correlated to chlorophyll content in the osmotically stressed leaves. Chlorophyll a (Chl_a), chlorophyll b (Chl_b), total carotenoids (C_x+c) and total chlorophyll (TC) in the seedlings were significantly reduced by osmotic stress, subsequently reducing maximum quantum yield of PSII (F_v/F_m) and photon yield of PSII (Φ_psii), thereby lowering net-photosynthetic rate (P_n) and inhibiting growth. Physio-biochemical parameters, including REL, F_v/F_m, and Φ_psii in oil palm seedlings were reduced more greatly by PEG-induced osmotic stress than by mannitol-induced stress. A deterioration in morphological characters, including leaf chlorosis, leaf burn, and green leaf area reduction were demonstrated in oil palm seedlings under osmotic stress induced by either mannitol or PEG. However, the toxic symptoms in oil palm seedlings under PEG-induced stress were severer than in those under mannitol-induced iso-osmotic stress, especially under severe osmotic stress.     

胡杨不同冠层叶片的形态特征及对水胁迫的响应

该研究以长势良好、冠高相近的3棵成年胡杨为采样株,在树冠垂直方向上进行3等分,取每个冠层东西南北4个方向的混合树叶为试验材料,研究不同冠层叶片的形态特征,以及在不同浓度PEG-6000下生理特性.结果显示:成熟胡杨植株树体上从树冠基部到树顶依次为披针形、卵形、宽卵形叶片,3种叶形指数、叶面积和叶柄长上存在着显著差异;水分胁迫时,第1层叶片通过维持细胞膜的稳定性来增加抗逆性,第2层叶片通过快速积累脯氨酸来适应干旱环境,第3层叶片通过维持可溶性蛋白含量的稳定性,提高代谢水平弥补水胁迫造成的伤害;在抗逆性隶属函数法评价上第3层叶片的综合抗逆性＞第2层叶片综合抗逆性＞第1层叶片综合抗逆性.     

绿竹P5CS基因的扩增及序列分析

采用同源克隆方法从绿竹基因组中获得2个P5CS基因组片段:Do P5CS1长度为2 178 bp,包含7个内含子和8个外显子,外显子编码序列为976 bp,编码325个氨基酸残基,编码蛋白分子量34.787 4 k D,等电点(PI)5.27,N端有一个氨基酸激酶超家族(Amino Acid Kinases(AAK)superfamily)功能区,C端有一个醛脱氢酶超家族(Aldehyde Dehydrogenase(ALDH)Superfamily)功能区;Do P5CS2大小与Do P5CS1外显子序列相同为976 bp,相似性达99.6%,但缺失内含子,推测Do P5CS2为返座假基因。该研究为基因全长序列的获取和功能分析以及通过分子生物学手段提高绿竹乃至其他竹类植物的抗逆性奠定基础。