朝鲜白头翁不定根分生结节形态学和解剖学观#br# 察

 以朝鲜白头翁幼嫩叶片诱导产生的不定根为材料诱导分生结节。采取Epon 812 树脂和石蜡 包埋切片技术分别对诱导初期的单个分生结节和培养5 ~ 6 周的组织进行组织切片研究。结果显示：（1） 不定根在诱导培养基上分化形成独立的表面光滑的球形分生结节。（2）单个分生结节顶端为3 ~ 4 层分生 细胞,其表皮和皮层上也观察到分生细胞。（3）分生结节分化后,结构上存在两种类型,一种为由分生 细胞、维管束、薄壁细胞和分化形成的小芽原基组成的结构,芽原基基部由排列整齐的表皮细胞组成, 不定芽之间结合较松散,与母体结合不紧密,易脱离,为独立的个体;另一种结构由排列规则的表皮细 胞环绕而成,其表皮细胞上广泛分布染色较深的球形、椭圆形或心形的体细胞胚状体,整个结构细胞大 小一致,无内部结构。结果证实,朝鲜白头翁不定根来源的分生结节上同时发生器官分化和直接体细胞 胚分化,分生结节也可分化形成胚性愈伤组织,通过愈伤组织间接再生体细胞胚。     

矮紫杉插条生根的解剖研究

用石蜡制片法室内解剖研究矮紫杉不定根的发生。结果表明：矮紫杉扦插生根属愈伤组织生根类型在切口处产生愈伤组织,再由愈伤组织内部分化形成分生组织结节和维管组织结节。在愈伤组织生长后期可见到大量的维管组织结节,当维管组织结节作单向分裂时形成根原基。     

Propagation characteristics of Eucalyptus globulus Labill. ssp. globulus stem cuttings in relation to their original position in the parent shoot

The rooting ability of one-node leafy cuttings of Eucalyptus globulus decreased rapidly with distance from the (decapitated) apical node. The young and immature leaves close to the shoot apex usually promoted rooting whereas the apex itself had little effect or was detrimental. In apical cuttings with an equivalent complement of leaves, increasing stem volume (and woodiness at the base of the cutting) slightly reduced rooting. The swelling of the stem at the base of shoots from coppice or potted plants also reduced rooting when present at the base of the cutting, whereas the inclusion of the root/shoot junction of seedlings promoted rooting. Cuttings from small seedlings rooted well and the roots sometimes emerged directly from the stem, whereas in non-seedling cuttings, roots nearly always arose from callus. The survival of cuttings in the propagation environment varied between trials. In apical cuttings with the same leaf complement, survival tended to increase with woodiness at the base of the cutting, but in contiguous one-node cuttings this tendency was overcome by the leaves, the soft apical nodes surviving better than the more proximal woodier nodes.     

Effect of leaf retention and flavonoids on rooting of Ilex paraguariensis cuttings

The effect of the mature leaf retention and the exogenous application of flavonoids (naringenin, quercetin and rutin at 30 μM for 12 h) was studied for adventitious rooting of Ilex paraguariensis cuttings. Softwood cuttings harvested from young 3-year-old plants and adult 10- and 20-year-old plants were rooted under intermittent fog. A strong correlation (r² = 0.72) between leaf retention and rooting was noted. The highest percentage of adventitious root formation (40%) was obtained when the leaf was artificially removed after 42 days of incubation. This data was supported by the histological analysis which provided anatomical evidence that cuttings have initiated root primordia by 21 days and the regenerated roots emerge through the epidermis after 35 days of incubation. A strong correlation between the position of the leaf and the site of roots regeneration was observed. A 100% of the rooted cutting with a single leaf only formed roots along the leaf axis at the base of the cutting. Quercetin increased the rooting percentage more than three times compared to the control and all flavonoids tested improved the distribution of roots around the stem without impacting the number of regenerated roots per rooted cutting from 20-year-old plants.     

Effects of boron-deficiency on anatomical structures in the leaf main vein and fruit mesocarp of pummelo [Citrus grandis (L.) Osbeck]

Summary

Boron (B)-deficiency is a nutritional problem in the citrus industry worldwide. Under B-deficient conditions, symptoms such as corky split veins, small fruit, low tree vigour, and low fruit yield appear. In this study, we investigated the anatomical responses of mature leaves and the albedo of mature fruit of HB pummelo [Citrus grandis (L.) Osbeck] to B-deficiency. Under B-deficient conditions, the numbers of parenchyma cells in the vascular bundles of the leaf and fruit mesocarp increased significantly. The ratio of the area of the phloem to the area of the vascular bundle also increased, while the ratio of the area of the xylem to the area of the vascular bundle decreased in both tissues. Moreover, we observed alterations in the xylem elements under B-deficient conditions. The average lengths of xylem vessels were 216.7 µm and 175.4 µm in leaf main veins and in fruit mesocarp, respectively, both significantly lower than the corresponding values in B-sufficient control plants. However, B-deficiency reduced the average diameter of xylem vessels only in leaf main veins. On the other hand, B-deficiency increased the numbers of pitted vessels to 63 and 59 among 100 xylem vessels sampled at random in leaf main veins and in the fruit mesocarp of B-deficient pummelos, respectively, while the corresponding numbers were 43 and 35, respectively, under B-sufficient conditions. B-deficiency also decreased the numbers of scalariform and reticulated vessels. Possible mechanisms for these anatomical modifications under B-deficient conditions are discussed.     

The effect of node origin on the development of cuttings of the tea plant (Camellia sinensis (L.) O. Kuntze)

The growth of roots and shoots of cuttings taken from nodes 3 to 9 on the parent stem, counting from the apex, have been compared. Comparisons also included dry weight of parts of the cuttings and leaf areas.

The number of cuttings with roots was unaffected by node origin; the weight of roots was similarly unaffected with the exception of one doubtful case.

Shoot growth, on the contrary, was found to be much more advanced in cuttings from older nodes, presumably because the buds were more highly developed. The cutting buds produced the flush-type growth and leaf forms typical of a mature tea bush.

The effect of node position on dry weights of cuttings was irregular. The greater loss of original leaves among cuttings from older nodes appeared to counteract the expected greater dry weight of these cuttings.     

冬春季温室切段扦插快繁马铃薯脱毒苗

在近几年试验研究的基础上,提出冬春季温室切段扦插快繁马铃薯脱毒苗模式.试验结果表明,温室温度25~28℃,相对湿度90%,光照5000~10000 lx,脱毒苗切段长2.5~3 cm,蘸生根液NAA 20 mg/L+KT 2 mg/L+GA30.5 mg/L,扦插密度1000~1300株/m2,扦插后喷雾生长调节液(NAA 5 mg/L+6-BA 0.5 mg/L+GA31 mg/L)和1/2 MS营养液或1/2 K5营养液+植物叶面肥,20~35 d后,苗高8~10 cm、茎节6~7个时,进行继代切段繁殖,如此重复继代切段繁殖3~4次,脱毒苗增殖20~25倍.     

叶片切除对番茄扦插苗茎基部糖含量及不定根发生的影响

以番茄品种中杂302 为材料，采用幼苗叶片切除和茎基部水扦插的方法，研究叶片切除对番茄扦插苗茎基部糖含量和不定根发生的影响。结果表明：切除幼苗叶片处理，改变了番茄扦插苗茎基部糖代谢相关酶SUS、CWIN 的活性和相对表达量，显著降低了茎基部葡萄糖、果糖、蔗糖和可溶性总糖的积累水平（P ＜ 0.05），抑制了不定根发生。表明保留适当的叶片数对番茄扦插苗不定根发生有非常重要的促进作用。     

东南景天茎插和叶插繁殖研究

研究了人工气候箱里东南景天在不同植物激素(NAA 1 000 mg/L、IBA 500 mg/L)和不同空气湿度(60％、80％)组合下茎插繁殖和在不同基质的叶插繁殖.结果表明:光照强度80％和温度20～25℃下东南景天叶插插穗在蛭石∶珍珠岩=1∶1基质上生根最快、根长最长、根量最多、成活率最高,且都显著优于其它基质(p＜0.05,下同);东南景天茎插在60％空气湿度下显著优于湿度80％的、插穗用IBA处理比用NAA处理要好;60％空气湿度下经IBA 500 mg/L处理过的东南景天茎插插穗的生根最快,成活率、累计发芽率、根量评分最高,发芽略慢,最长根长略短,但植株整体生长状态最好,且都明显优于其它处理,是进行茎插繁殖的最佳处理组合.该研究为东南景天的快速繁殖、资源保护以及重金属污染土壤修复应用提供技术保障.     

桃PpSnRK1α在番茄中过表达对营养胁迫下植株生长的影响

以番茄(Solanum lycopericum)超表达桃SnRK1(蔗糖非发酵蛋白激酶–1)基因PpSnRK1α的株系及野生型为试材,研究在养分供应不足时SnRK1对植株生长的影响。结果表明,低营养条件下,转基因番茄叶片和根系中的Sn RK1酶活性比野生型高41.55%和39.46%;功能叶片的净光合速率平均比野生型高18.98%;低营养胁迫12 d的叶片SOD、POD、CAT活性比野生型高35.56%、28.85%和14.90%;根系活力比野生型高26.39%;茎和叶中氮磷含量显著高于野生型,钾含量两者差别不大,在根系中氮磷含量差别不大,而钾含量显著高于野生型,且氮素向地上部茎和叶中的分配比率增加。上述结果说明,在营养缺乏条件下,超表达PpSnRK1α可以提高番茄功能叶净光合速率,促进植株对氮素的吸收利用,从而延缓叶片衰老。     

镉胁迫对‘丽春’桃树体中镉积累及根系生长的影响

以水培‘丽春’桃（Prunus persica L.Batsch.）幼苗为试材,研究不同镉浓度（1、2 、4 、8、16、64 mg.L^-1 ）和pH 5.6的条件下,根的生长长度,生长速率以及树体器官、茎组织、根、叶亚细胞结构中镉积累的变化。结果表明,处理2 d后,营养液中镉浓度小于4 mg.L-1时根生长速率较对照显著（P<0.05）增加,表现为促进生长,随处理天数的增加,刺激生长效果减弱。当营养液中镉浓度超过4 mg.L^-1、处理时间超过6 d,根生长速率随镉浓度增加而减少,表现为抑制生长。营养液中镉浓度为64 mg.L^-1时,根系停长。镉在桃树体中的积累量：器官中,根>茎>叶;茎组织中,木质部>韧皮部;根、叶亚细胞中,细胞壁>可溶性部分、细胞核>线粒体;根细胞壁中镉含量显著（P<0.05）高于其它亚细胞组分,这说明细胞壁在抵御桃树受镉胁迫时起到关键性作用。     

Vector analysis in the study of the nutritional status of Philodendron cultivated in compost-based media

Compost (CP) made from 70% ligno-cellulosic compounds and 30% sewage sludge was studied as a component of growing media in a 6-month Philodendron cultivation. CP's agronomic viability was evaluated via four plant-growth media containing 25–50–75–100% CP and white sphagnum peat (WP) in comparison to a commercial substrate with white and black peat. Plant nutrition conditions were investigated by determining macro- (TKN, P, K, Ca, Mg and micronutrients (Mn, Fe, Cu, Zn, Na) and heavy metals (Ni, Cd, Cr, Pb) in roots and shoot tissues. Data were compared by vector analysis against control. Even if no leaf injuries were visible after 6-months’ growth, a CP ratio of up to 50% caused growth depression of canopy tissues, as attested by the 37 and 36% reduction in total leaf dry weight and leaf area, respectively. Root growth decline was also notable at 25% CP, where 38% root dry weight reduction implied a significant increase (46%) in shoot–root dry weight ratio. The investigation on nutrient tissue content showed high accumulation of Ni, Fe, Cr, Zn, Cd, Mn, Mg and P in roots; Mg appeared related to K deficiency. Above-ground nutritional status showed a severe lack of P, Mg and Mn. Vector analysis suggests the sewage sludge CP in Philodendron pot cultivation produces many such effects like direct toxic action and antagonistic action, resulting in a general nutrient imbalance in plants.     

狗蔷薇类根体和类原球茎发生发育的组织学研究

以狗蔷薇叶片为对象观察其类根体和类原球茎发生发育的过程。发现叶片外植体叶柄维管束的原形成层细胞在2,4-D的诱导下分裂并扩大形成狭长的微管组织细胞,进一步衍生形成根源基细胞,根源基细胞分裂形成根尖分生组织,并最终形成类根体。类根体具有根冠、生长点、伸长区和根毛区,类根体只有初生结构,不具备次生结构。携带有愈伤组织的类根体在含TDZ的1/2MS培养基和光照协调作用下,根尖分生组织消失并分化成成熟的薄壁细胞,中柱鞘上部的细胞形成胚性愈伤组织,其分化为胚性细胞并形成新的分生中心,突破皮层和表皮,进而形成类原球茎。     

对羟基苯甲酸胁迫下尖孢镰刀菌侵染草莓根系的组织结构观察

以‘丰香’（Toyonoka）和‘土特拉’（Tutela）草莓品种为试材,利用石蜡切片技术研究了在自毒物质对羟基苯甲酸胁迫下,尖孢镰刀菌草莓专化型（Fusarium oxysporum f. sp. fragariae）侵染根系引起的组织结构变化。结果表明：对羟基苯甲酸胁迫下,尖孢镰刀菌菌丝在‘丰香’和‘土特拉’根系中的侵染速率明显加快,对根系表皮、皮层、中柱薄壁细胞及导管壁结构的破坏程度也明显加重,且对‘丰香’的破坏程度明显重于‘土特拉’。对羟基苯甲酸胁迫显著提高了‘丰香’和‘土特拉’根系组织含菌丝导管的比例,分别为22.5%和15.8%;但‘土特拉’根系含胶状物导管的比例为26.3%,明显高于‘丰香’（16.3%）。在对羟基苯甲酸胁迫下,‘土特拉’根系组织产生胶状物比‘丰香’早。‘土特拉’单独接菌处理根系内含有侵填体导管的比例为1.6%,明显高于‘丰香’单独接菌处理和对羟基苯甲酸胁迫下‘土特拉’接菌处理（1.0%和1.2%）。对羟基苯甲酸胁迫下接种尖孢镰刀菌可明显加重草莓根系组织受损程度,且‘丰香’枯萎病发生较重。     

土壤水分对西瓜幼苗生长的影响

以种子大小不同的4个品种为试验材料,研究了土壤水分胁迫条件下西瓜幼苗的生长状况和几个生理特性变化。结果表明:种子大的品种,幼苗个体大,素质好,苗期生长状况也好;土壤水分条件对西瓜幼苗生长具有显著影响,地上部干物质积累量随着土壤含水率降低而降低,但根系干物质积累量与土壤水分呈负相关;在土壤水分胁迫下,西瓜大种子品种具有大根系吸水优势,而小种子品种以较小蒸腾面积和较强叶片保水能力为适应对策。     

Effect of the amount and position of leaf tissue on the yield of single-truss tomatoes

Immediately after first anthesis, leaf removal treatments were applied, involving varying amounts of leaf tissue at different positions on the stem of widely spaced single-truss tomato plants.Yield was shown to be related to leaf dry weight, while leaf position did not appear to be important, except for those leaves closest to the roots. The leaves and roots were shown to be in competition with the reproductive tissues for dry matter.     

The Vacuum-Operated Nutrient Delivery System: hydroponics for microgravity

A nutrient delivery system that may have applicability for growing plants in microgravity is described. The Vacuum-Operated Nutrient Delivery System (VONDS) draws nutrient solution across roots that are under a partial vacuum at approximately 91 kPa. Bean (Phaseolus vulgaris L. cv. Blue Lake 274) plants grown on the VONDS had consistently greater leaf area and higher root, stem, leaf, and pod dry weights than plants grown under nonvacuum control conditions. This study demonstrates the potential applicability of the VONDS for growing plants in microgravity for space biology experimentation and/or crop production.     

银杏吸收根营养元素吸收及分配规律的能谱分析

 能谱分析银杏吸收根组织对营养元素的吸收规律，结果表明：1．根对营养元素的吸收有两次高峰，第一次出现在营养液培养处理后的4～6 h左右，第二次出现在10-24 h左右；2．营养元素的吸收规律和在银杏根不同组织分布与培养液中元素种类、离子的类型和银杏根系对营养元素需求特性有关;3．银杏根系中K、Na元素积累量较高，显示银杏是一种代谢强度大、耐盐的植物。     

不同废弃物混合基质对脱毒马铃薯原原种生长发育和经济效益的影响

网棚内,采用无土栽培模式,研究了不同废弃物混合基质与脱毒马铃薯生长发育和经济效益间的关系,结果表明：粗沙、牛粪、糠醛渣、菇渣、锯末屑按体积比0.3：0.1：0.2：0.2：0.2配制的混合基质符合脱毒马铃薯原原种生长发育规律,与单采用蛭石（CK）相比,脱毒马铃薯原原种株高、茎粗、叶片数、根系长分别增加了2.98cm,0.16cm,2.16片,0.59cm;存活率、单株粒质量、单粒质量、单株粒数、繁殖效率分别增加了15.30%,8.15g/株,1.72g,0.47粒/株,156.51粒/m2;产值、利润、投资效率分别增加了46.95元/m2,113.36元/m2,16.62元/元。处理间差异显著性经LSR检验达到显著和极显著水平。     

Growth,allocation of N and carbohydrates,and stomatal conductance of greenhouse grown apple treated with prohexadione-Ca and gibberellins

Summary

Potted M.26 apple (Mahis domestica) liners were treated with the gibberellin biosynthesis inhibitor prohexadione-Ca (Apogee®) at 0 to 500 mg l”¹ as a foliar spray. Apogee inhibited stem elongation, leaf formation, total leaf area and shoot dry weight, while significantly increasing specific leaf weight, root dry weight and root: shoot ratio, regardless of rate. Foliar application of gibberellin A4₊₇ (GA4₊₇) at 200 mg l”¹ to Apogee-treated plants one day later reversed these effects, especially stem elongation, root dry-matter production and root: shoot ratio. Apogee increased N concentration in stems but not in leaves and roots. There was no effect on the pattern of N allocation amongst organs. GA4+7 increased leaf N concentration but decreased stem and root N concentrations compared with untreated controls, with N allocation shifting from roots to stem. Total nonstructural carbohydrates (TNC), expressed either on a concentration or content basis, increased in all parts of the Apogee-treated plants, due to increased levels of starch rather than soluble sugars, without altering allocation pattern. Conversely, GA4₊₇ reduced TNC levels (mainly starch levels) in all parts, with the pattern of allocation slightly shifted from roots to stem. The afternoon decline in stomatal conductance occurred earlier in the Apogee treated plants, measured 10 d after stem elongation had ceased. Starch buildup in the Apogee-treated plants appeared to be associated with this effect, suggesting an involvement of a feedback inhibition of photosynthesis in the Apogee-induced stomatal control.