马铃薯块茎的生长模型及块茎生长率与细胞分裂的关系

块茎的生长率各不相同,其生长的时间变化状态呈S型曲线。现发现逻辑斯蒂克(Logistic)方程适宜于用来模拟块茎的生长。块茎的大小与块茎的生长率及生长的时间密切相关,但生长率是影响块茎大小的主要因素。块茎绝对生长率的加权平均与块茎细胞数量的直线相关证明了块茎的生长在很大程度上受细胞分裂控制。块茎生长率与细胞膨大无显著相关。     

Comparison of methods for measuring dormancy of potatoes

Comparisons were made of different methods of measuring length of the dormant period of Russet Burbank potato tubers as affected by time of planting and harvest. The study resulted in the following conclusions: 1) when measured from planting or tuber initiation to sprouting, the dormant period of tubers harvested on the same date was longer from an early planted crop than from a late planted crop. 2) When measured from harvest to sprouting, the dormant period was shorter for tubers from an early compared to a late planting. 3) With the same planting date and different harvest dates, when measured from planting or tuber initiation to sprouting, the dormant period was shorter for tubers from an early compared to a late harvest. 4) On the other hand, with the same planting date, when measured from time of harvest to sprouting, the dormant period was longer for tubers from an early compared to a late harvest. Planting date to sprouting was considered the best practical field measure of dormancy since it closely correlated with tuber initiation to sprouting, a method which was more accurate but difficult to determine. Both methods were much better than harvest date to sprouting which is commonly used. In addition, larger tubers from earlier planting had shorter dormancy than smaller tubers regardless of method of measurement due to a probable earlier set. From later plantings, tuber size had no relationship to length of dormancy. Moisture stress significantly reduced dormancy of Lemhi, Russet Burbank, and Nooksack but the Butte cultivar was only slightly affected.     

Tuber initiation and development in irrigated and non-irrigated potatoes

Tuber initiation and development are processes basic to potato production and are particularly critical in areas with short growing seasons. It is important to know how and to what extent management decisions affect these processes in order to maximize the yield of marketable tubers. A two-year field study, conducted in southcentral Alaska, examined top growth, tuber initiation, and tuber development in eight potato cultivars grown with and without irrigation. Plants of the cultivars Allagash Russet, Bake-King, Green Mountain, Kennebec, Lemhi Russet, Russet Burbank, Shepody, and Superior were harvested weekly throughout the growing season, and top dry weight, numbers of tubers, and individual tuber fresh weights were recorded. Top dry weight was reduced by moisture stress shortly after emergence in 1993, and about one month following emergence in 1994, when early-season soil moisture was greater. The weight of tubers was similarly affected within approximately 5 wk of emergence in 1993 and 6 weeks in 1994. Tuber weight at harvest was increased two-to three-fold by irrigation in all cultivars. The number of tubers each plant set was affected by irrigation in most, but not all, cultivars. Some varieties (Lemhi Russet in 1994, Allagash Russet both years) set more tubers than were maintained through the growing season. Tuber remnants found during sample collection indicated that tuber reabsorption had occurred. Irrigated Green Mountain had more than one tuber initiation period during the season, whereas other varieties such as Shepody maintained a relatively constant number of tubers following initial tuber set. Tuber size distribution at the end of the growing season showed that larger tubers were favored by irrigation.     

Potato Stolon and Tuber Growth Influenced by Nitrogen Form

Abstract

Potato tuber initiation and its growth are key processes determining tuber yield, which are closely related to stolon growth, and are influenced by many factors including N nutrition. We investigated the influences of different forms of nitrogen (N) on stolon and tuber growth in sand culture with a nitrification inhibitor during 2010 – 2011, and using two potato cultivars. Plants supplied with NO₃-N (N as nitrate, NO₃^-) produced more and thicker stolons than those supplied with NH₄-N (N as ammonium, NH₄⁺) at tuber initiation stage. In the plants fed NO₃-N, the stolon tips swelled or formed tubers earlier and produced more tubers than in those fed with NH₄-N. However, no significant difference was observed among N forms in terms of tuber yield at harvest, this may have been because of the shoot growth rate at tuber initiation stage was lower in the plants fed NO₃-N. During the tuber bulking stage, the difference in shoot DWs among N forms began to decrease, and the shoot DW of plants fed NO₃-N was even heavier than those fed NH₄-N in some cases. The influence of N form on potato plant growth may therefore vary with the potato growth stage.     

Glycoalkaloid accumulation during tuber development of early potato cultivars

Summary Plants of early potato cultivars were sampled at successive harvests during tuber development and individual tubers were analysed for α-solanine and α-chaconine using high-performance liquid chromatography. Mean tuber total glycoalkaloid concentration (α-solanine plus α-chaconine) per plant decreased with time and statistically significant differences between cultivars were observed in the patterns of decline during tuber growth. The mean tuber ratio of α-chaconine to α-solanine increased during tuber development and was also affected by genotype. Total glycoalkaloid concentration for individual tubers of marketable sizes (up to 50 g fresh weight) exceeded the safety limit of 20 mg per 100 g fresh weight for cultivars Home Guard and British Queen but not for Rocket. These differences were attributable to differences in both rates and patterns of glycoalkaloid accumulation during tuber development, although in all cultivars results were consistent with glycoalkaloid accumulation occurring in the expanding peripheral cell layers of tubers for a considerable period after tuber initiation.     

The effect of some environmental factors on potato tuber numbers

Summary Five experiments studied the effects of shading, temperature and stolon growth medium on stolon and tuber formation. The lowest numbers of stolons and tubers were produced at the higher and lower nodes. Numbers of primary stolons and tubers were relatively stable across nodes and treatments and variation in total numbers was largely due to changes in numbers of lateral and branch stolons. In the field, 70% shading reduced numbers of stolons and tubers by reducing lateral and branch stolons, while in hydroponics, 45% shading and temperatures at initiation had no effect on tuber numbers. In both environments later planting tended to reduce numbers of stolons and tubers. There were large effects of the physical environment, with compost producing three times as many tubers as dry vermiculite. The potential number of tubers may be determined by the number of stolons and the environmental conditions affecting stolon formation and development.     

马铃薯丰产群体植株光合产物日变化规律的研究(四) 淀粉含量及其日变化

全生育期中,马铃薯丰产群体和一般群体植株叶片和茎秆的淀粉含量日变化趋势相同,呈昼高夜低的抛物线形的变化。两群体植株块茎淀粉含量的日变化,在生育前期和后期变化趋势一致,均表现为夜高昼低,而块茎增长期,由于丰产群体块茎夜间增长非常迅速,而出现夜间低峰现象。整个生育期间两群体块茎淀粉含量高于叶片和茎秆,并均随生育期的推移而逐渐增加,但丰产群体始终低于一般群体。前期叶片淀粉含量高于茎秆,后期茎秆和叶片含量相近。茎秆既是马铃薯的支撑和运输器官,也是光合作用的重要辅助器官。     

Growth rate and carbohydrate metabolism of potato tubers exposed to high temperatures

Summary The effect of high tuber temperature (30 °C) on the growth rate and carbohydrate metabolism of tubers was studied with 3 cultivars differing in heat tolerance. Subjecting individual tubers to 30°C for 6 days caused cessation of tuber growth. During this period, non-treated tubers (20°C) on the same plant increased in volume. At 30°C, incorporation of¹⁴C-labelled assimilates into the ethanol-insoluble fraction (mainly starch) as well as the starch content was significantly reduced. In contrast, the incorporation of¹⁴C-labelled assimilates into the sugar fraction was not affected by high tuber temperature. At 30°C the activity of some of the enzymes involved in starch metabolism was depressed. Varietal differences in responses of tuber growth rate and carbohydrate metabolism to high tuber temperature were insignificant. From these preliminary results it is concluded that high soil temperatures may decrease starch content of potato tubers directly by inhibition of the conversion of sugars into starch.     

Invertase activity as affected by cytokinin-like compounds during potato tuberizationin vitro

Acid invertase plays an important role in plants by hydrolyzing sucrose. Compounds exhibiting cytokinin activity were examined for their effects on acid invertase activity at three tuberization stages of potato,Solanum tuberosum L. Single nodal segments from the cultivar Atlantic were cultured on Murashige and Skoog (MS) medium with 6% sucrose and maintained under a 16-hr photoperiod. Media were supplemented with either 2 mg kinetin/1, 0.1 mg thidiazuron/1,1.0 mg AC243, 654/1 (a benzyl nitroguanidine), or 0.1 mg AC239, 604/1 (a phenyl nitroguanidine). Basal acid invertase activity was measured in stolon segments at three morphologically distinct tuberization stages: (1) “hook,” (2) “swelling,” and (3) “initiation.” The onset of tuber initiation was significantly advanced by kinetin and thidiazuron compared to controls. Stolons elongated during the hook and swelling stages until tubers were initiated. Basal acid invertase activity in stolons cultured on control medium significantly increased from hook stage to swelling stage and then decreased slightly when tubers were initiated. At the hook stage, highest basal acid invertase activity occurred when the segments were treated with kinetin and thidiazuron. Kinetin and thidiazuron induced basal acid invertase activity significantly decreased following the hook stage to tuber initiation. Basal acid invertase activity were significantly lower in stolons treated with nitroguanidines than the control activity following the hook stage of development. During the swelling and tuber initiation stages, nitroguanidines-treated segments showed reduction in basal acid invertase activity similar to segments treated with kinetin and thidiazuron treatments. Tuber initiation was preceded by a stimulation of basal acid invertase activity followed by a decrease prior to tuber initiation. Kinetin and thidiazuron stimulated enzyme activity early in the growth of stolons which may have resulted in faster stolon growth and in earlier tuber initiation. The two nitroguanidines, although able to mimic many cytokinin effects in bioassays, did not seem to act in the same way as kinetin.     

A device for measuring the growth of individual potato tubers non-destructively and precisely

Summary A device for measuring the short-term fluctuations in volume of individual tubers is described. Its accuracy is mostly independent of tuber growth stage, shape and malformations. The coefficient of variation of volume of a tuber of 40 cm³ was usually well below 0.15% when the tuber was measured four times.     

Effect of year,location, and harvest on susceptibility of cultivars to internal heat necrosis in North Carolina

Internal heat necrosis (IHN) is a physiological disorder that affects potato quality. The influences of year, location, harvest date, and tuber size on the incidence of IHN were investigated toward developing an IHN screening technique. In 1989 and 1990, potato cultivars were grown at two North Carolina locations with normal season (90–105 days) and late (115–125 days) harvests at each location. At each harvest, yield data were taken, tubers were divided into three size classes (1= 48–64 mm, 2 = 65–83 mm, and 3 = > 83 mm), and 20 tubers were evaluated for amount and severity of IHN within each size class. More IHN was observed when tubers were sampled in size class 2 versus size class 1; there were not enough tubers in size class 3 to evaluate. Cultivars differed significantly in their susceptibility to IHN. Location did not influence the amount of IHN observed. Time of harvest also did not significantly affect incidence of IHN. The amount of IHN varied greatly depending on the year. Resistant and susceptible checks are strongly recommended to be included in future IHN field studies to monitor yearly variation in IHN severity.     

Parenchyma cell growth in potato tubers I. Different tuber regions

Enlargement rates of starch-storage parenchyma cells during growth of Kennebec and Russet Burbank potato cultivars were determined for cortical, perimedullary, and pith tissuues of bud ends, midsections, and stem ends of tubers. Average volumetric size of parenchyma cells increased 7 to 18x during growth of Russet Burbank tubers, with the greatest increases occurring in cortical and perimedullary cells of bud ends and midsections, and the least in stem ends and pith tissues. In Kennebec tubers parenchyma cells in both stem end and midsection increased only 5 to 8 x, whereas increases in bud ends ranged from 8 to 20 times. Cell enlargement to tuber enlargement ratios appproached unity early in growth of Russet Burbank tubers. As tubers increased beyond the 45 g size, cell enlargement and tuber enlargement rates were essentially equal. Calculations of cells per unit tissue volume agreed with ratio determinations. The timing of such unity appeared to be delayed in Kennebec tubers, and was not quite as pronounced as in Russet Burbank tubers. This may have been due to differences in growth rates of individual tubers in response to cultural conditions. In general, cells of harvestmature Kennebec tubers were about 60% as large as similar cells of Russet Burbank tubers.     

Manipulation of tuber-size distribution of a potato crop

Summary Tuber-size distribution is regulated by many diverse, interacting mechanisms and is therefore difficult to understand and manipulate. It is determined by plant density, number of stems per plant, number of tubers per stem, and yield. Seed size and plant number per unit area are easy to control, but stem number is affected by less controllable factors. Interactions between stems of different types are important for tuber-size distribution. The hormonal regulation of stolonization and tuberization is still unknown, but under the conditions of north-west Europe the process of tuber set (which is also poorly understood) makes a greater contribution to the final number of tubers than tuberization. The total yield is also relevant, because it affects both the average tuber size and its variation. Tubers on the same stem differ in timing, rate and duration of growth. The resulting hierarchy in sink strength is not consistent over time. Several mechanisms are suggested for this hierarchy.     

Effects of shoot,root and stolon temperature on the development of the potato (Solanum tuberosum L.) plant. III. Development of tubers

Summary The cultivars Bintje and Désirée were growth with their shoots, roots and stolons at different temperatures, to study the effects on tuber development. More tuber sites were initiated in ‘Bintje’ when the air, root or stolon temperature was increased but a combined increase of air and root temperature greatly reduced the number of sites. In contrast, each temperature increase reduced the number of tuber sites in ‘Désirée’ but an increase in temperature in one compartment usually increased the number of tubers set. The relative tuber set was enhanced by a combination of high stolon temperature and low root temperature. Especially an increase in air temperature reduced tuber yield and tuber dry-matter content, but increasing stolon temperature had the largest effects on the induction of second growth. Stolon and tuber development, dry-matter partitioning and initiation of second growth responded differently to variation in temperature around different plant parts suggesting that these processes are affected by different regulation mechanisms.     

Effect of second growth on the quality of tubers as seed in the cultivar Record

Summary Seed quality in a crop harvested in 1984 was compared in tubers which either, (a) were unsprouted prior to harvest (normal), (b) had formed secondary chain tubers prior to harvest (primary), (c) secondary chain tubers. Normal and primary tubers formed substantial sprout growth during storage, while there was little sprout growth from secondary tubers. Plants derived from these seed tuber types differed, in terms of emergence, number of emerged stems, and tuber number. It is concluded that the tuber types can be considered to vary in terms of physiological age; normal and primary tubers appear to be physiologically older than the secondary tubers. This variability in seed condition can lead to variability in the performance of the subsequent crop.     

The effect of short periods of shading at different stages of growth on the development of tuber number and yield

Summary Shading potato plants at the beginning of tuber initiation for a period of 12 days reduced the rate of tuber formation and growth; but after the shades were removed tuber formation continued to give more tubers and the shaded plants eventually produced 30% more tubers than the unshaded, with similar yield. Shading for 12 days during the early stages of rapid tuber bulking had no effect on tuber number or survival, though bulking rate was temporarily reduced, leading to a reduction in final yield. These number results indicate that tuber number can be influenced by the weather during the period of tuber initiation.     

马铃薯库建成动态研究

在马铃薯块茎的形成和增长过程中 ,小薯不断地形成、退化或转化成大中薯 ,其中出苗2 8d以后的 2～ 3周是决定大中薯数的关键期。在不同密度及施肥处理下 ,马铃薯块茎体积及干重的增长均呈S型曲线变化。单株块茎体积随密度增加而减少 ,适量施用氮、磷、钾 ,可增加块茎体积、单株结薯数和大中薯数 ,其中磷钾肥可使结薯时间提前 ,过量氮肥则推迟结薯时间 ;随密度的增加 ,块茎日增重逐渐降低 ,适量增施磷、钾肥可提高库的充实度 ,增加产量。在本试验因素中量 (适量 )组合 ,底西芮品种单株块茎体积最大增长速率为 2 5 7392ml d ,块茎干重的最大增长速率为 10 6 82 6 g d ;种植密度 4 5 0 0株 6 6 7m2 时 ,单株结薯数为 13 5个 ,大中薯数平均为 10个 ,单产可达 30 0 0kg 6 6 7m2 以上     

Is dormancy breaking of potato tubers the reverse of tuber initiation?

Summary Tuber formation is a well orchestrated physiological event that involves many metabolic changes. Dormancy gradually develops in potato tubers from the moment cell division in the stolon tip has stopped and the tuber starts to develop. Dormancy breakage may be the reverse of dormancy initiation suggesting that there may be similarities between tuber induction and dormancy development. Based on a literature review it is concluded that, when comparing tuber induction and the breaking of dormancy, hormonal activities are only partly reversed, whereas carbohydrates and enzyme activities might be reversed. For more definite conclusions more research should be done to assess precisely the moment of dormancy breaking. Moreover, measurements on events associated with tuber induction and dormancy breaking should be carried out using the same techniques and the same material. Molecular genetic analyses may provide well-defined markers for the timing of breaking of dormancy.     

马铃薯块茎生长过程中内源赤霉素和脱落酸含量的变化

以紫花白和晋薯２号两个品种为材料，研究了马铃薯同一个体植株中，处于不同生长阶段上的块茎，其内源ＧＡ３和ＡＢＡ含量的变化规律．结果表明：开始形成的块茎（块茎直径１ｃｍ左右）中ＡＢＡ和ＧＡ３含量最高，但ＧＡ３／ＡＢＡ的比值则较低；之后随着块茎的膨大，ＡＢＡ和ＧＡ３的含量均逐渐降低，但ＡＢＡ的降低速度大于ＧＡ３，从而使ＧＡ３／ＡＢＡ的比值逐渐增高，到块茎成熟时，ＡＢＡ和ＧＡ３都有所增加。而由块茎迅速膨大到成熟的过程中，ＧＡ３／ＡＢＡ的比值则又逐渐降低。两个品种在块茎生长过程中，内源ＧＡ３和ＡＢＡ的含量具有相似的变化规律．成熟期块茎平均直径较大的紫花白，当块茎直径小于５ｃｍ左右时，其中ＧＡ３的含量大于相应大小的晋薯２号，后期两个品种之间则基本无差异；而ＡＢＡ的含量在两个品种之间则始终无多大差异；因此使ＧＡ３／ＡＢＡ的比值在块茎直径小于５ｃｍ以前紫花白大于晋薯２号。因此我们认为ＧＡ３和ＡＢＡ在块茎开始形成与膨大及成熟的整个生长过程中，对块茎的形成和生长发育具有负反馈调节与协同作用．     

Field performance of potato minitubers with different fresh weights and conventional seed tubers: Multiplication factors and progeny yield variation

Summary Multiplication factors and progeny yield variation in crops from minitubers of five weight classes (ranging from 0.13–0.25 g to 2.00–3.99 g) and conventional seed tubers were studied in field experiments in three years. Multiplication factors were calculated as the number and weight of progeny tubers produced per planted tuber or per unit planted tuber weight. They were lower for the lighter minitubers when calculated per tuber and higher when calculated per weight. Yield variation was described by coefficients of variation for the number and weight of progeny tubers produced. Variation over individual plants of a crop was higher in stands from the lighter minitubers. Variation over plots within a field was sometimes higher for the lighter minitubers, but variation over years was similar for all minituber classes. Variation over plots in progeny tuber weight was higher for minitubers than for conventional tubers.