Osmotic priming of true potato seed: Effects of seed age

Summary The effects on germination and early seedling growth of presowing true potato seed in water or gibberellic acid (GA) at 1500 ppm and of priming in −1.0, −1.25 and −1.5 MPa solutions of KNO₃+K₃PO₄ were studied using 30, 18, 6 and 3/4 month-old seed. The influence of light during presowing on the effectiveness of treatments was also investigated. Overall, priming in the light at −1.0 MPa was the most, and GA the least successful treatment for enhancing emergence and subsequent seedling growth. Though GA increased final emergence from about 20 to 70% in the most recently harvested lot (3/4 mo), the rate and extent of final germination or emergence in this dormant seed was still much lower than that of the nondormant lots (6–30 mo), especially when the latter were primed. For all lots, dry weight per seedling was 40% lower in dormant than in nondormant seed, and 20% higher when seeds were primed at −1.0 MPa than when GA treated. In conclusion, the use of nondormant seed may be a requirement for both effective priming and sowing of potato crops via true seed.     

Seed quality as affected by nitrogen during true potato seed production and moisture conditions during storage

The objective was to investigate the effects of moisture conditions in storage at 21 C (± 3) on true potato seed (TPS) germination and seedling vigor. The influence of supplemental nitrogen (N) during seed production on these effects was also studied. One set of TPS was stored exposed to ambient humid (> 80% RH) air; the other was stored dry (sealed with silica gel). Germination tests were performed at 7, 11, and 14 months of seed storage. Seedling vigor tests were made at 14, 20, and 23 months. The rate of germination was mostly affected by the moisture conditions during storage. Seed stored dry germinated faster than TPS stored in humid ambient air. The rate of germination increased with time in storage and the percentage of germination was always high (≥ 95%) in dry seed produced with high N. Seedling vigor was mostly affected by N treatments during seed production. High-N seed had a much higher rate and percentage of emergence and seedling dry-weight levels than low-N seed, particularly when stored dry. Seedling vigor criteria decreased with time in storage in low-N seed; in high-N seed, the rate of emergence increased and the percentage of emergence was always high (≥ 95%). In conclusion, the TPS should be produced with high N and stored dry for sowing under unfavorable conditions.     

Selection against inbred seedlings in mixtures of inbred and hybrid true potato seed

Summary The effect of selection against weak plants was studied in artificial mixtures of hybrid (S₀), first self-pollinated generation (S₁), and second self-pollinated generation (S₂), true potato seed. Selection of vigorous seedlings in true seed populations raised in flats from mixtures of S₀ (25%), S₁ (50%), and S₂ (25%) seed increased the frequency of hybrids to 71%. In another study, two mixtures of S₀ and S₁ seed (1∶3 and 1∶1) were densely sown in beds to produce seedling tubers. Elimination of weak plants during population thinning and subsequent interplant competition significantly reduced the frequency of inbred plants. The resulting seedling tuber progenies were planted in the field and mean yields from the two mixtures of S₀ and S₁ seed were 96% and 99% of related completely hybrid progenies. The implications of these results for TPS production are discussed.     

利用TPS夏播生产优质实生种薯的研究——夏播TPS生产实生种薯

本文是利用TPS夏播生产优质实生种薯的初步研究结果,它由种著大小试验、实生苗密度试验,夏播TPS生产实生种薯试验三部分组成.这三个试验是在1989~1992年进行的.试验揭示了种薯大小与后代生长发育的关系,认为3g以上的小整薯均可直接播于大田生产实生种薯,土壤肥力和实生苗密度是影响夏播生产实生种薯的主要因素,土壤肥力更重要.实生苗的定植密度应大于120株/m~2.初步证明,利用TPS夏播生产实生种薯是可行的.     

植物生长调节剂对毛萼紫薇种子萌发及幼苗生长的影响

自然条件下毛萼紫薇Lagerstroemia balansae结实率很高,但自然萌发率和成苗率极低。适合的植物生长调节剂处理种子,能够有效打破种子休眠、有效促进幼苗生长。本研究采用TTC染色法测定毛萼紫薇种子的生活力,比较5种植物生长调节剂GA3、TDZ、IAA、6-BA和NAA处理下毛萼紫薇种子的发芽率、发芽势及对幼苗生长的影响。结果表明:(1)毛萼紫薇种子生活力较低;(2)200 mg/L GA3处理的种子发芽势,发芽率较高,幼苗长势良好;其次是0.02 mg/L的TDZ处理,再次是200 mg/L IAA的处理;(3)1~20 mg/L的6-BA和NAA处理对毛萼紫薇种子的萌发无促进作用。上述结果表明:GA3、TDZ、IAA能有效促进毛萼紫薇种子的萌发及幼苗生长。     

特用玉米种子沙引发处理对其萌发及幼苗生理特性的影响

以糯玉米、爆裂玉米和甜玉米3种特用玉米为材料,测定沙引发处理后种子萌发指标、幼苗形态和生理指标的变化。结果表明,沙引发能显著提高糯玉米和甜玉米的种子活力,对3种特用玉米的幼苗生长具有显著的促进作用,但对种子发芽率无显著影响。沙引发处理显著提高了3种类型特用玉米幼苗的过氧化物酶(POD)和超氧化物歧化酶(SOD)活性,显著降低了丙二醛(MDA)含量。沙引发效果受基因型影响,对种子萌发的促进作用表现为糯玉米>甜玉米>爆裂玉米;对幼苗生长的促进作用表现为甜玉米>爆裂玉米>糯玉米。沙引发能够提高幼苗体内抗氧化酶的活性,从而增强幼苗对外界环境的适应能力。     

Rice seedling establishment as affected by cultivar,seed coating with calcium peroxide,sowing depth,and water level

Inconsistent seedling establishment is a constraint to the adoption of direct seeding of lowland rice (Oryza sativa L.) in the tropics. Rice cultivars with superior seedling establishment in flooded soil have been recently identified. The establishment of these tolerant cultivars was compared with a control cultivar with and without calcium peroxide-coated seed under various combinations of water level and sowing depth. Water level had little effect on seedling establishment when seed were sown on the soil surface, but establishment was reduced by raising the water level when seed were sown below the soil surface. Calcium peroxide-coated seed established better than the tolerant cultivars at 13- and 25-mm sowing depths, but their seedlings were shorter and less vigorous than those of tolerant cultivars. Tolerant cultivars and coated seed had longer mesocotyls than controls. Sowing tolerant cultivars beneath a flooded soil surface at less than 13 mm assists achievement of consistent seedling establishment in lowland rice production.     

浸种和外源激素处理对毛马齿苋种子发芽的影响

为提高毛马齿苋种子播种出苗率,分析不同时间浸种以及采用GA3、NAA和6-BA 3种外源激素处理对其种子发芽的影响。结果表明：浸种处理没有提高毛马齿苋种子的发芽势和发芽率的效果;GA3、NAA和6-BA三种激素浸种处理均能提高毛马齿苋种子的发芽势和发芽率;最适宜的浸种浓度分别为GA3 30 mg/L、10～20 mg/L NAA或6-BA 30 mg/L。其中GA3有效浓度范围较宽泛,建议采用,但GA3处理不能解除该种子发芽的需光性。     

不同浓度配比的PEG、二甲基亚砜和水杨酸引发对玉米种子抗寒性的影响

以玉米杂交种创奇518新种子为材料,以不同浓度配比的聚乙二醇（PEG）、二甲基亚砜和水杨酸组合作为引发剂,采用L₉（3⁴）正交试验设计,通过低温种植处理,研究提高玉米种子抗寒性的3种引发剂的最佳浓度配比。结果表明,不同配比引发处理的玉米种子发芽势、发芽率、苗鲜重、活力指数、过氧化物酶（POD）和过氧化氢酶（CAT）活性均表现出明显差异。以浓度为20%的PEG、浓度为0.5%的二甲基亚砜和浓度为0.007%的水杨酸组合处理种子的发芽率、活力指数最高,幼苗长势整齐一致,POD和CAT较对照有明显提高。     

种子吸水速率对玉米种子活力测定的影响

以农大108、先玉335、郑单958和中农大4号为材料,采用划伤种皮及改变发芽时种胚的摆放位置两种处理,测定吸水速率和活力,研究吸水速率对种子活力检测的影响。结果表明,不同玉米品种吸水速率和活力水平不同,两者之间没有明显的相关性。对于同一品种,划伤种皮及种胚朝下处理,吸水速率加快,可显著提高种子的活力指数、幼苗长度等检测值。中农大4号划伤种皮后活力指数提高0.229,苗长增加0.7 cm;郑单958种胚朝下处理,活力指数提高3.563,苗长增加2.95 cm。在进行种子活力检测时,应充分考虑到种皮透性对检测结果的影响,玉米种子采用纸上发芽时,应统一使种子的胚接触发芽纸,检测到的种子活力才更加准确可靠。     

赤霉素、PEG对玉米种子活力的影响

以玉米创奇518陈种子为材料,利用赤霉素（GA₃）、聚乙二醇（PEG）及其复合引发对玉米种子进行处理,研究玉米种子活力的变化。结果表明,不同引发处理间玉米种子的活力指数、发芽势、发芽率及株高均表现出明显的差异。聚乙二醇具有明显提高玉米种子发芽率的作用,赤霉素能够促进植株的生长,提高玉米出苗速度。     

Comparative efficacy of surface drying and re-drying seed priming in rice: changes in emergence, seedling growth and associated metabolic events

In seed priming, seeds are soaked in a solution of low water potential and dried back to their original weight. This study was conducted to evaluate the comparative performance of different seed priming treatments and to investigate whether re-drying is essential or not? Seeds of fine grain aromatic rice (Oryza sativa L.) cultivar Super-Basmati were subjected to hardening, osmohardening with CaCl₂ and KCl (ψ _s ?1.25 MPa) each for 24 h (one cycle), and hydropriming and ascorbate priming (10 mg L^?1) for 48 h. Seeds were primed in two sets. In one set after each treatment, seeds were given three surface washings with distilled water and dried back near to original moisture contents with forced air. In the other case, after surface washings with distilled water, seeds were surface dried using blotting paper and sown immediately. All the priming treatments improved the emergence, seedling growth and reserve metabolism. Use of surface drying was more effective for rice seed invigoration, as evident from earlier and synchronized seedling emergence. Moreover, shoot and root length, seedling dry weight, root score, α-amylase activity, soluble sugars and dehydrogenase activity were also improved, although germination percentage and leaf score were similar from both strategies. Results suggested that surface drying, rather than re-drying close to original weight, was more effective, while among the treatments, osmohardening with CaCl₂ was the most effective. Increasing rice production with judicious use of water is need of the day, and aerobic rice cultivation is an attractive alternative for this purpose. However, poor and erratic stand establishment is one of the major hindrances in its wide scale adoption. In this regard, seed priming techniques are pragmatic approaches to achieve proper stand establishment in the new rice culture. They help in improving seedling density per unit area under optimal and adverse soil conditions and may be opted to improve the performance of aerobic rice.     

马铃薯实生幼苗生长缓慢原因的探讨

本试验通过马铃薯实生幼苗与西红柿、苋菜、黄花烟幼苗形态特征、生理特性相比较,得到如下结论:a.幼苗干物重、叶面积、茎粗等与种子贮藏物质有极显著的相关性,实生种子小是实生幼苗生长缓慢的原因之一。b.实生种子发芽温度以20℃左右为宜,超过25℃发芽将受到抑制。c.实生种子贮藏物质以脂肪为主,脂肪转化为结构物质缓慢,因此实生种子即使在最适发芽条件下也需5～6天才能发芽。d.实生幼苗光合产物在根、茎、叶中分配不合理,分配到茎中较多(高达40%),分配到叶片的比其它作物少,致使叶面积小,光合产物少,这是实生幼苗生长缓慢的又一原因。e.实生幼苗光合产物分配状况是其生理特性决定的,实生幼苗茎中过氧化物酶、蔗糖酶活性高,吲哚乙酸氧化酶活性低,表明茎的代谢旺盛,因而促进了茎的生长;而叶中过氧化物酶、蔗糖酶活性低,吲哚乙酸酶活性高,表明叶片生理代谢弱,致使叶片生长缓慢。f.DTO—33不论是在根系生长、叶面积增长、干物质积累上,还是在匍匐茎产生、膨大方面都比克疫天然籽显出较强的优势。     

Advancing growth vigor of seed potatoes by a haulm application of gibberellic acid and storage temperature regimes

Seed tubers that are planted soon after their harvest give low yields because of dormancy and low growth vigor. In the research reported in this paper, we investigated the advancing effect of a haulm application of gibberellic acid (750 g GA/ha) 6 days before haulm pulling and its interaction with storage temperature regimes on the growth vigor of immaturely harvested seed tubers of three cultivars. The effects on tuber yield were also examined in one experiment. The storage regimes were: 18 C continuously, hot pre-treatments of different duration (different periods at 28 C and subsequently 18 C) and a cold pre-treatment (20 days at 2 C and subsequently 18 C). Both a foliar spray with GA and storage at 28 C enhanced physiological aging of the tubers and greatly advanced the growth vigor, without negative effects on the morphology of the plants. There was a clear interaction between the GA treatment and the storage temperature regime. At early planting, the effect of the treatments on tuber yield were small for Diamant (short dormancy), but strongly positive for Désirée and Draga (long dormancy).     

杂交稻制种田九二○用量与种子中GA_3含量及F_1代产生徒长苗的关系

在杂交稻制种时，为了调节不育系的生长，促进异交结实，提高制种产量，喷施九二①是一项重要措施。近年来，九二①的单位面积施用量有逐年增大的趋势。由此引发出一个颇有争议的问题，即大剂量（明显超过每667m’8～12g的正常用量）的施用九二①会不会引起F；代幼苗产生类似恶菌病的徒长苗？因为近些年来，有些地方的杂交稻中恶苗病徒长苗明显增多，甚至造成严重损失。然而对其产生的原因看法却不一致，一种观点认为”－”，这与杂交稻制种时过量使用九二0有关；另一种观点则认为’‘’，制种田使用九IO后，种子中有赤霉素残留，但不会引…     

多巴胺引发对盐胁迫下水稻种子萌发及幼苗生长的影响

[目的]探讨多巴胺(Dopamine,DA)引发对盐胁迫下水稻种子萌发及幼苗生长的影响.[方法]以新疆自育水稻品种新稻17号为研究对象,分别用0(纯水)、0.1、0.5、1、1.5 mg/L的DA溶液(分别用S0、S0.1、S0.5、S1、S1.5表示)引发种子,采用浓度为100 mmol/L的NaCl溶液模拟盐胁迫,...     

几种化学药剂对杂交籼稻汕优63自然老化种子引发效果研究

用聚乙二醇（PEG）、聚乙烯醇（PVA）、KNO3、PEG＋KNO3、PVA＋KNO3等几种化学药剂对自然老化的杂交籼稻汕优63种子进行引发效果研究,以筛选最佳处理方法。结果表明,从引发效果和经济实用两方面考虑,以0.5%PVA＋1.0%KNO3处理1 d为最佳。经过该处理的汕优63自然老化种子的发芽率显著提高,比对照（63.0%）提高了11.7个百分点,活力指数、发芽势、苗高、苗重也均较对照显著提高,且成本较低。     

干旱胁迫下多效唑包衣对玉米种子萌发及幼苗生长的影响

研究在干旱胁迫下多效唑包衣玉米种子对玉米种子萌发及幼苗生长的影响。结果表明,多效唑包衣能明显提高玉米种子的发芽率、发芽指数及活力指数,其中发芽率高出正常生长的6%,使玉米幼苗变矮,茎粗和根长增加,根冠比极显著提高。测定玉米幼苗的生理生化指标表明,多效唑包衣处理能明显地降低幼苗的脯氨酸含量和丙二醛含量,提高可溶性糖含量和SOD活性,有利于增强玉米幼苗的抗旱能力。     

Thermal time approach to predicting seedling emergence dates of red clover,white clover and lucerne in farm fields

A practical method for predicting seedling emergence dates of red and white clovers, and lucerne is proposed. The germination response at seven different constant temperatures ranging from 5 to 35°C was examined. Germination rate, which is a reciprocal of the duration for 50% germination of seeds, was linearly regressed against temperature to calculate the base temperature and thermal constant of seed germination. The calculated values were 3·9°C and 15·8 degree days for red clover, 4·2°C and 13·6 degree days for white clover, and 2·9°C and 17·7 degree days for lucerne. Using the base temperatures, thermal constants, and the daily mean air temperatures at the study site, the seedling emergence dates of the three forage legumes were predicted. At the same time, in an outdoor pot experiment, seeds of these legumes were sown approximately every 3 weeks and seedling emergence dates were determined. The predicted dates of seedling emergence generally fitted the observed dates. Another prediction was attempted using the base temperatures, thermal constants, and normal daily mean air temperatures recorded over more than 30 years in the study site. This prediction showed that the seedlings of the three forage legumes began to emerge at the beginning of April and could continue to emerge until the beginning of November when their non‐dormant seeds were present in the site, and that when the seeds were sown from mid‐November of one year to late March of the next year, the emergence of seedlings was delayed until the beginning of April.     

杂交水稻种子活力的研究

采用５种方法测定杂交水稻特优６３,汕优６３,协优５７,协优６３和特优５５９等新种子活力,结果表明;不同组合间种子活力存在显著差异,发芽的生理测定一加速老化试验的简化活力指数均与种子田间成苗率存在显著正相关,选用发芽的生理测定结合加速老化试验,综合判定种子活力水平是较为准确的。