柑桔矮化砧木的生理生化预选指标研究

以７４－１积、紫花宜昌橙、Ｒｕｓｋ枳橙、Ｔｒｏｙｅｒ枳橙、江南柑、９２号红桔和蟹橙为标准系列砧木,研究了它们的生理生化特征,从中筛选出了茎还原性糖含量、叶片还原性糖含量、叶片氨基酸含量、茎蛋白质含量、叶片过氧化物酶活性５个柑桔矮化预选指标和叶片可溶性糖含量、叶片蛋白质含量２个辅助预选指标。     

水杉异砧嫁接植株体内激素的分布和含量变化(简报)

同一生育期不同器官或同一器官不同生育期的水杉异砧嫁接植株砧穗各器官中均含有GA3、IAA、ZT和ABA,以GA3含量最高。10、11月休眠前期,接穗水杉叶片中GA3、ZT和ABA含量显著高于砧木叶片,砧木叶片中IAA含量分别是接穗叶片的1．5和1．9倍。砧木根和接穗叶芽、花芽中4种激素含量均高于砧穗的茎,而接穗的雌球花芽则高于雄球花芽。     

水杉异砧嫁接植株体内激素的分布和含量变化

同一生期育不同器官或同一器官不同生育的水杉异砧嫁接植株砧穗各器官中均含有ＧＡ３,ＩＡＡ,ＺＴ和ＡＢＡ,以ＧＡ３含量最高,１０、１１月休眠前期,接穗水杉叶片中ＧＡ３,ＺＴ和ＡＢＡ含量显著高于砧木叶片,砧木叶片中ＩＡＡ含量分别是接穗叶片的１．５和１．９倍。砧木根和接穗叶芽,花芽中４种激素含量均高于砧穗的茎,而接穗的雌球花芽则高于雄球花芽。     

矮砧果树为什么变矮

在果树矮化密植栽培中,有以下几种方法使果树变矮:①利用矮化砧或矮化中间砧;②采用紧凑型品种;③采用致矮的农业技术;④使用生长调节剂。现仅用矮化砧为例,分析一下矮砧果树变矮的原因: 什么是矮化砧木具有矮化作用的砧木,叫矮化砧。矮化砧具有比其接穗细胞渗透势低的生物学特性。由于细胞的渗透势与溶质浓度成反比,所以,矮化砧组织细胞渗透势低而细胞液浓度较高。通过嫁接后,将与其接穗细胞形成浓度的逆生理差。     

3种薯蓣属植物珠芽糖类含量变化与茎叶生长的关系

以山药、日本薯蓣和黄独3种薯蓣属植物为材料,研究珠芽育苗中其茎叶生长与珠芽内的干物质、淀粉、可溶性糖、还原糖含量和淀粉酶活性变化的关系.结果表明: 3种薯蓣在茎蔓生长过程中珠芽内的干物质和淀粉含量均逐渐降低.山药和黄独的珠芽可溶性糖含量在茎蔓生长初期不断增加,随着茎蔓节数继续增加又逐渐降低,而还原糖含量在叶片展开前不断增加,叶片展开后又急剧降低;日本薯蓣珠芽的可溶性糖和还原性糖含量随着茎蔓节数增加逐渐上升,但保持相对较低水平.3种薯蓣珠芽内α-淀粉酶活性均强于β-淀粉酶,其在茎蔓和叶片生长中发挥重要作用.研究发现,薯蓣珠芽内淀粉主要在α-淀粉酶作用下转化分解为还原糖和可溶性糖,从而为茎蔓和叶片生长提供能量,且还原糖含量与叶片生长的关系更为密切.     

柑桔中间砧对接穗叶片和基砧根系碳水化合物含量的影响

以华红脐橙/3 种中间砧/枳为试材进行田间试验,研究不同中间砧对接穗叶片和基砧根系中碳水化合物含量的双重影响。结果表明,接穗叶片可溶性糖含量、基砧根系淀粉和总糖含量的年动态变化趋势基本相似,而在接穗叶片淀粉含量年动态变化的早期趋势和总糖含量年动态变化的后期趋势、基砧根系可溶性糖含量的年动态变化趋势上则有明显的差异。在一年中的绝大多数时期里,接穗叶片和基砧根系的 3 种碳水化合物含量在不同中间砧之间有明显的差异。     

嫁接对盐胁迫下西瓜幼苗体内离子和内源激素含量与分布的影响

以小型西瓜‘秀丽’为接穗、耐盐砧木瓠瓜‘超丰抗生王’为砧木,以自根嫁接苗为参照,分析了砧木嫁接对NaCl胁迫下西瓜幼苗根、茎、叶中离子和内源激素含量的影响。结果表明:(1)盐胁迫下,自根嫁接苗Na+主要积累在地上部,K+含量和K+/Na+比下降幅度大;砧木嫁接苗大部分Na+积累在根系中,K+含量和K+/Na+比下降幅度小且在不同部位皆高于自根嫁接苗。(2)盐胁迫下,自根嫁接苗吲哚-3-乙酸(IAA)以及玉米素和玉米核苷的总量(Z+ZR)在根系和接穗茎中显著增加,在叶片中明显下降,赤霉素(GA3)含量在不同部位保持不变或明显增加;而砧木嫁接苗不同部位IAA和(Z+ZR)的含量均显著增加,GA3含量在不同部位保持不变或明显下降。(3)盐胁迫下,两种嫁接组合根系和茎中脱落酸(ABA)含量均明显下降,叶片中ABA含量则显著增加。(4)盐胁迫下,自根嫁接苗和砧木嫁接苗根系和接穗茎中IAA/(Z+ZR)的比值均明显上升,叶片中明显下降,但砧木嫁接苗上升和下降幅度均远大于自根嫁接苗。研究表明,瓠瓜根系对进入根系的Na+具有截留作用;采用瓠瓜砧木嫁接可有效防止Na+在西瓜接穗地上部尤其是在叶片中的大量累积,从而防止离子毒害的发生;瓠瓜砧木嫁接植株体内具有较高的K+含量和K+/Na+比,可有效维持盐胁迫下西瓜嫁接植株体内的离子稳态;瓠瓜砧木嫁接植株体内具有较高的IAA和(Z+ZR)含量,IAA/(Z+ZR)比值较高,对提高西瓜嫁接植株盐胁迫耐性起到了积极的作用。     

‘LD-1'砧米良一号猕猴桃的耐涝性

猕猴桃是一类不耐涝的植物,为了解决猕猴桃的涝害问题,吉首大学近年来尝试用‘LD-1’作为猕猴桃的耐涝性砧木。该研究以米良一号实生苗砧米良一号猕猴桃和‘LD-1’砧米良一号猕猴桃为材料,观测根系淹水后叶片可溶性糖含量、丙二醛含量、叶绿素含量、可溶性蛋白质含量、SOD 活性和形态的变化规律,探讨了‘LD-1’砧米良一号猕猴桃的耐涝性。结果表明：(1)米良一号实生苗砧米良一号猕猴桃根系淹水后,可溶性糖含量6 d 后极显著(P<0.01)升高;丙二醛含量8 d 后显著(P<0.05)升高;叶绿素含量和可溶性蛋白质含量没有显著变化;SOD 活性6 d 后显著(P<0.05)升高,8 d 后不再有显著变化;叶片2 d 后出现轻度萎蔫,10 d后全部枯死。(2)‘LD-1’砧米良一号猕猴桃根系淹水后,可溶性糖的含量4 d 后显著(P<0.05)升高;丙二醛含量、叶绿素含量、可溶性蛋白质含量和 SOD 活性无显著变化;叶片10 d 后未出现显著的萎蔫和枯死现象,30 d 后仍正常。这说明米良一号实生苗砧米良一号猕猴桃耐涝性较弱,‘LD-1’砧米良一号猕猴桃耐涝性较强,‘LD-1’作砧木显著增强了米良一号猕猴桃的耐涝性。该研究结果为‘LD-1’在米良一号猕猴桃栽培上的应用提供了依据。     

柑桔抗寒性与其膜脂脂肪酸组分的关系研究

作者采用气相色谱法对5年生宜昌橙、本地早、国庆一号、锦橙、沙田柚枳砧嫁接树,在抗寒锻炼过程中叶片的膜脂脂肪酸含量的变化进行了研究。结果表明:在日均温为24℃左右时,柑桔叶片开始积累不饱和脂肪酸,冬季叶片不饱和脂肪酸含量最高,比夏季要高60%以上,春季解除抗寒锻炼时,叶片膜不饱和脂肪酸含量下降,饱和脂肪酸含量上升。膜不饱和脂肪酸的积累与气温呈负相关关系。冬季叶片、茎韧皮部和叶绿体等组织器官的膜脂脂肪酸不饱和度、亚麻酸与亚油酸的比值,以及种子中亚油酸与棕榈酸含量之比,均与柑桔品种的抗寒性成正相关。     

云南黑籽南瓜砧木对低温下嫁接黄瓜生理特性的影响

以‘津研4号’黄瓜(Cucumis sativus‘Jinyan No.4’)为接穗,云南黑籽南瓜(Cucurbita ficifoliaBouch啨)和黄瓜为砧木,研究了低温条件下黄瓜/云南黑籽南瓜嫁接株(黄瓜/南瓜)、黄瓜/黄瓜嫁接株和自根黄瓜株叶片的蔗糖(Suc)、葡萄糖(Glc)和可溶性蛋白质(Pr)含量的变化以及叶片羧化效率(CE)及不同叶位叶片、不同节位茎段中异戊烯基腺嘌呤核苷(iPA)含量的差异。结果表明,黄瓜/南瓜嫁接株叶片的Suc、Glc及Pr含量和CE值均显著高于自根黄瓜株和黄瓜/黄瓜嫁接株,自根黄瓜株与黄瓜/黄瓜嫁接株间差异不显著。iPA在嫁接植株和自根植株茎中均呈梯度分布,其含量在生长锥中最高,其次为上部茎段,下部茎段中的含量最低;自根黄瓜株和黄瓜/黄瓜嫁接株茎中的iPA含量显著低于黄瓜/南瓜嫁接株,而叶片中iPA含量显著高于黄瓜/南瓜嫁接株。研究结果表明,以黑籽南瓜为砧木可提高嫁接黄瓜对低温的耐受性。     

铁胁迫对三种柑橘砧木的生长、生理特性及铁分布的影响

以枳壳、酸橙和红橘三种柑橘砧木实生苗为材料,采用溶液培养法研究了铁胁迫对其生长、生理特性及铁分布的影响.结果表明:缺铁胁迫(0 μmol·L-1)时,三种柑橘砧木的生长指标及叶片叶绿素含量均显著低于低铁(5 μmol·L-1)和适量铁(50 μmol·L-1)处理;三者叶片和根系的POD、CAT活性显著降低,SOD活性...     

Root and stem hydraulic conductivity as determinants of growth potential in grafted trees of apple (Malus pumila Mill.)

The anatomy of the graft tissue between a rootstock and its shoot (scion) can provide a mechanistic explanation of the way dwarfing Malus rootstocks reduce shoot growth. Considerable xylem tissue disorganization may result in graft tissue having a low hydraulic conductivity (k(h)), relative to the scion stem. The graft may influence the movement of substances in the xylem such as ions, water and plant-growth-regulating hormones. Measurements were made on 3-year-old apple trees with a low-pressure flow system to determine k(h) of root and scion stem sections incorporating the graft tissue. A range of rootstocks was examined, with different abilities of dwarfing; both ungrafted and grafted with the same scion shoot cultivar. The results showed that the hydraulic conductivity (k(hroot)) of roots from dwarfing rootstocks was lower compared with semi-vigorous rootstocks, at least for the size class of root measured (1.5 mm diameter). Scion hydraulic conductivity (k(hs)) was linked to leaf area and also to the rootstock on to which it was grafted, i.e. hydraulic conductivity was greater for the scion stem on the semi-vigorous rootstock. Expressing conductivities relative to xylem cross-sectional areas (k(s)) did not remove these differences suggesting that there were anatomical changes induced by the rootstock. The calculated hydraulic conductivity of the graft tissue was found to be lower for grafted trees on dwarfing rootstocks compared to invigorating rootstocks. These observations are discussed in relation to the mechanism(s) by which rootstock influences shoot growth in grafted trees.     

马哈利樱桃矮化砧的DNA甲基化水平及模式分析

该研究利用MSAP技术,对25株矮化马哈利樱桃和25株半矮化马哈利樱桃进行甲基化水平和模式分析,以探讨其矮化的表观性状与其基因组甲基化修饰的关系。结果表明:(1)从64对引物中筛选出15对引物,在半矮化组中共扩增4 577个条带,其中半甲基化336个,全甲基化1 274个;在矮化组中共扩增4 444个条带,其中半甲基化349个,全甲基化1 383个;t检验和方差分析表明,矮化组与半矮化组在总甲基化水平和全甲基化水平上差异极显著,在半甲基化水平上差异显著,矮化组甲基化水平高于半矮化组。(2)半矮化组单态性位点23个,多态性位点136个;矮化组单态性位点17个,多态性位点142个,表明矮化组多态性高于半矮化组。(3)多态性类型分析表明,矮化组出现A4类型的频率较半矮化组高,A2类型的频率较半矮化组低,即矮化组中发生超甲基化的位点多于半矮化组,且‘马哈利’基因组甲基化多态性位点主要发生在双链内侧甲基化位点以及超甲基化位点上。研究认为,马哈利樱桃矮化和半矮化的基因组甲基化水平及模式存在差异,马哈利砧木的矮化性状与其基因组甲基化修饰有关。     

重庆三峡库区柑橘硼营养状况及其影响因子

为了解重庆三峡库区柑橘叶片硼营养状况及其影响因子,在该区域12个主产县(区)的代表性果园采集叶片样品954份和土壤样品302份,测定叶片硼含量,并分析了土壤有效硼、土壤pH值、品种、砧木和树龄对叶片硼营养的影响.结果表明: 该区域柑橘叶片硼含量不足(<35 mg·kg^-1)的果园比例达41.6%,土壤有效硼含量不足(<0.5 mg·kg^-1)的果园比例高达89.4%,柑橘叶片硼含量与土壤有效硼含量的相关性未达显著水平.土壤pH值、品种、砧木和树龄均影响叶片硼含量.pH值4.5～6.4土壤上的柑橘叶片硼含量显著高于pH值6.5～8.5土壤上的柑橘;品种间叶片硼含量为:温州蜜柑>柚类>夏橙>普通甜橙>杂柑>脐橙;枳砧和酸柚砧柑橘叶片硼含量显著高于枳橙砧和红橘砧柑橘;3～8年生柑橘树叶片硼含量适宜(35～100 mg·kg^-1)样品比例比8年生以上柑橘树高6.6%.     

Hydraulic resistance components of mature apple trees on rootstocks of different vigours

Dwarfing of fruit trees is often achieved through the use of dwarfing rootstocks. Dwarf trees are characterized by sustained reductions in vegetative growth during the lifetime of the tree. The dwarfing mechanism is not well understood, but it has been hypothesized that hydraulic properties of the rootstock and the graft union are involved. It is hypothesized here that leaf- or stem-specific resistance of at least one hydraulic component of the water transport system would be negatively correlated with rootstock 'vigour', and this could be useful for selection of rootstocks. Hydraulic resistance (R) of fully grown apple trees on a variety of rootstocks of different 'vigours' was measured. Most measurements were with the evaporative flux (EF) method, where water uptake measured with sap flow sensors was related to the pressure gradient from soil (taken as pre-dawn leaf) and midday root (taken as covered root-sucker), stem (from covered leaf), and exposed and shaded leaf water potentials (Psi(l)). R of trees on dwarfing M9 rootstock was compared with that of more vigorous MM106 and MM111 rootstocks in Israel and Vermont, USA. In Israel, M9 consistently had higher leaf-specific hydraulic resistance (R(l)) in the soil to scion stem pathway, but this difference was only significant for one summer. R was larger in M9 between the root and stem, implicating the graft union as the site of increased resistance. In Vermont, R(l) of 9- and 10-year-old trees on six rootstocks of various vigours was not consistently related to vigour, and stem-specific resistance (R(s)) increased with increasing vigour. High pressure flow meter (HPFM) measurements gave a lower R than the EF method in all but one case, perhaps indicating a significant amount of xylem dysfunction in these trees, and demonstrated the increased resistivity of stem sections that included dwarf graft unions as compared with non-graft stem sections. It is concluded that stem- and leaf-specific R are not consistently positively correlated with dwarfing, although the increased resistivity of the graft union in dwarfing rootstocks may influence the transport of water and other elements across the graft union, and therefore be involved in the dwarfing mechanism.     

Cotton shoot plays a major role in mediating senescence induced by potassium deficiency

The objective of this study was to determine the roles of shoot and root in the regulation of premature leaf senescence induced by potassium (K) deficiency in cotton (Gossypium hirsutum L.). Two contrasting cultivars (CCRI41, more sensitive to K deficiency; and SCRC22, a less sensitive cultivar) were selected for self- and reciprocal-grafting, using standard grafting (one scion/one rootstock), Y grafting (two scions/one rootstock) and inverted Y grafting (one scion/two rootstocks) at the seedling stage. Standard grafting was studied in the field in 2007 and 2008. There were no obvious differences in senescence between CCRI41 and SCRC22 scions while supplied with sufficient K. However, SCRC22 scions showed significantly greater K content, SPAD values (chlorophyll content), soluble protein content and net photosynthetic rates than CCRI41 scions while grown in K deficient solution or soil, regardless of rootstock cultivars, grafting types, growth stage and growth conditions. Also, SCRC22 scions had greater yield and less variation in boll weight either between upper- and lower sympodials, or between proximal and distal fruit positions from the main stem in the field under K deficiency, probably owing to reduced leaf senescence. Although the effect of rootstocks on leaf senescence under K deficiency was significant in some cases, the scion cultivars explained the highest percentage of variations within grafting treatments. The shoot-to-root feedback signal(s), rather than high shoot demand for K nutrition, was involved in the shoot regulation of premature senescence in cotton plants, achieved possibly by altering root K uptake.     

The physiological and nutritional responses of seven different citrus rootstock seedlings to boron deficiency

Key message

Carrizo citrange was the most tolerant citrus rootstock to B-deficiency and some physiological performance could be attributed to the decreased mineral nutrient concentrations caused by B-deficiency.

Abstract

Boron (B) is an essential microelement for normal growth and development in vascular plants, and adequate B nutrition is crucial for agricultural production. Although citrus plants are not classified as the most sensitive species to B-deficiency, the occurrence of B-deficiency has been reported in the major citrus producing countries of the world, including the east and south of China. In this study, in order to evaluate the effects of B-deficiency on plant growth, root-morphological traits, B and other nutritional responses of citrus rootstock and to investigate the relationship between this physiological performance and mineral nutrients seven common rootstock seedlings, including Trifoliate orange (TO), Carrizo citrange (CC), Chongyi tangerine (CT), Red tangerine (RT), Cleopatra mandarin (CM), Fragrant citrus (FC), and Sour orange (SO), were treated by B-deficiency (0 mg L^?1) or moderate B (0.25 mg L^?1). All the seedlings were grown in hydroponics situation with modified 1/2-strength Hoagland’s solution under greenhouse conditions for 10 weeks. The results showed that B-deficiency inhibited the growth and development of all tested citrus rootstocks, but substantial differences were observed among these rootstocks. Different visible symptoms were observed both in the leaf and root. Corking of the leaf veins and leaf yellowing symptoms were observed on all rootstock genotypes except on CC, which exhibited a little discoloration at the end of the experiment. In addition, root growth of the citrus seedlings were also decreased by B-deficiency, but the decreases were more obvious in TO and FC. It was worth noting that B-deficiency inhibited lateral root growth and development more significantly than tap root, but not in lateral root initiation. The different performance of these rootstock genotypes indicated that CC was the most tolerant while TO was the most sensitive to B-deficiency. In addition, under B-deficiency conditions, not only the B concentration, but also the other mineral nutrient concentrations were influenced, especially in Mg, Fe and Mn. This change in nutrient concentrations might partly contribute to the seedlings’ physiological performances under B-deficiency.     

Drought tolerance of apple rootstocks: Production and partitioning of dry matter

The drought tolerance of the commercial apple ( Malus domestica Borkh.) rootstocks M9, M26, M27 and MM111, and some new selections from the rootstock breeding programme at HRI-East Malling (AR69-7, AR295-6, AR360-19, AR486-1 and AR628-2), was assessed using potted, glasshouse-grown, unworked rootstocks. After an initial period of growth under well-watered conditions the amount of irrigation was gradually reduced, for some treatments, to simulate natural drying in the soil. At the end of a six-month growth period, the rootstocks were harvested and the production of dry matter and its partitioning to various plant parts determined. The rootstocks exhibited large differences in shoot and root dry matter, and root length but not all the rootstocks showed declines in root mass or length in response to the droughting treatment. The dwarfing rootstocks tended to have smaller amounts of both coarse (>2 mm diameter) and fine roots (<2 mm diameter), than the more vigorous rootstocks. Irrespective of rootstock or irrigation treatment there was a close linear relationship between coarse and fine root. There was also no change in the length/weight relationship for fine roots irrespective of rootstock or irrigation treatment, i.e. 42 m of fine root weighed 1 g dry weight. In some cases the amount of root produced could be directly correlated with the rootstock known potential to control scion vigour, but this was not true for all the rootstocks examined. The absence of this relationship was particularly evident in some of the new selections of rootstock. The possible causes for these differences, compared with commercially used rootstocks, is discussed in relation to the origin and parentage of the rootstock selections. Despite this lack of a root length/vigour relationship, the amount of dry matter partitioned to shoot growth reflected the rootstocks' known vigour. The different responses of these rootstocks to drought are discussed along with their implications for understanding the mechanisms by which rootstocks are thought to dwarf scion shoots.     

Investigation of tissue structure and xylem anatomy of eight rootstocks of sweet cherry (Prunus avium L.)

Reduction of crop yield from high water stress is a serious agricultural problem worldwide, which is expected to intensify under future global change scenarios. Efforts are underway worldwide to improve crops resistance to drought. One possible way is the careful choice of rootstock-scion combination. It is well known that water stress symptoms of grafted cherry trees to a large extent depend on the rootstock variety. Scions grafted on dwarf rootstocks show more serious stress symptoms, so it is reasonable to hypothesize that these symptoms and the tissue structure of the rootstock stem are connected. This paper examines this connection for 1-year-old seedlings of eight cherry rootstocks with different degree of vigor. Tissue structure was observed via scanning electron microscope images. Investigations were focused on number, size, and distribution of vessels, because they are principally responsible for water transport. Stem porosity (i.e., the total vessel area relative to the stem area, in cross-sectional view) of the dwarfing rootstocks was found to be significantly smaller than that of the others, supporting the notion that stem anatomical characteristics might contribute to water stress sensitivity.