The oriental hybrid lily (Lilium oriental cv. Sorbonne) is an economically important flower noted for its pink petals. Flower quality is determined by plant height, number of flowers per plant, and flower diameter. The commercial value can be increased by improving flower quality through cultural practices such as exogenous application of hormones; however, information on this practice is unavailable for this lily hybrid. In the present study, we soaked lily bulbs for 24 hours in one of four concentrations of abscisic acid (ABA) or one of three concentrations of the ABA biosynthesis inhibitor fluridone before subjecting the bulbs to a cold storage treatment at 4 °C. During cold storage, bulbs were sampled and buds were collected every 10 days for 80 days (that is, lasting eight times). The ABA and gibberellic acid 3 (GA3) contents of buds of treatments that showed a significant difference with the control were measured in a 10-day interval. Greenhouse experiments with different cold storage durations of bulbs that measured height, flower number per plant, and flower diameter were conducted. The interaction of hormone treatments and cold storage duration played nonsignificant roles in parameters of flower quality. Exogenous fluridone application to bulbs at 12 mg·L−1 improved flower quality: height and flower number increased significantly compared with the control, but flower diameter did not change. ABA had no effect on flower quality. Because the fluctuation of endogenous GA3 is more remarkable than ABA after the application of fluridone that led to the improvement of flower quality, it can be inferred that this influence on flower quality is achieved through fluridone’s regulation on the content of endogenous GA3. A low endogenous GA3/ABA ratio was associated with improved flower quality: 12 mg·L−1 fluridone decreased the GA3/ABA ratio in most times of the cold treatment. In addition, cold storage duration affected flower quality; the 50-day cold storage can achieve the highest height, the most flower number, and bigger flower diameter simultaneously. The results of the present study suggest that soaking bulbs in 12 mg·L−1 fluridone before cold treatment followed by 50 days of cold storage before planting will increase plant height and flower number per plant.
Liu Yang, Zhongkui Xie, Zhijiang Wu, Yajun Wang, Zhihong Guo, Yubao Zhang, and Ruoyu Wang
Zhihong Gao, Weibing Zhuang, Liangju Wang, Jing Shao, Xiaoyan Luo, Binhua Cai, and Zhen Zhang
Estimating chilling requirements is crucial for identifying appropriate cultivars for a given site, for timing applications of dormancy-breaking chemical agents, and for predicting consequences of climate change. For temperate-zone fruit species such as japanese apricot, productivity is reduced when chilling requirements are not adequately satisfied. In our study, we obtained chilling and heat requirements for flowering of six japanese apricot cultivars, which spanned the range of flowering times in this species for three successive years. Different methods for determining chilling requirements were evaluated and compared, and correlations among chilling requirements, heat requirements, and flowering date were established. The dynamic model proved to be the best for determining the chilling requirements of japanese apricot. The results showed a range of chilling requirements ranging from 26.3 to 75.7 chill portions and a narrow range of heat requirements, from 1017.7 to 1697.3 growing degree-hours (GDH). A very high correlation (R = 0.9797) between flowering date and chilling requirements and a low correlation (R = 0.4298) between flowering date and heat requirements suggest that flowering date in japanese apricot is mainly a consequence of the chilling requirements of the different genotypes, whereas heat requirements contribute a limited effect to the variation in flowering dates. Chilling requirements and heat requirements were positively related with a low correlation coefficient (R = 0.4211).
Yingchao Lin, Dejun Kong, Zhihong Wang, Yi Chen, Zhixiao Yang, Chun Wu, Hui Yang, and Lili Chen
Tobacco is traditionally an industrial crop that is used for manufacturing cigarettes. However, due to health concerns and global tobacco control movements, alternative uses of tobacco are urgently needed to support tobacco farmers and vendors. Tobacco is also an oilseed crop with an oil yield ranging from 30% to 40 of its dry weight. However, there is still no information on the effects of nitrogen application on tobacco seed yield and seed oil production. The objective of this study was to evaluate the effects of N fertilization (90, 120, 150, and 180 kg·ha−1 N) on the seed yield, oil content, fatty acid composition, and seed germination characteristics of tobacco plants at two locations. The results showed that applying increasing amounts of N to tobacco plants significantly increased their total seed yields and oil content. Nitrogen application also modified the fatty acid composition of the seed oil, as more unsaturated fatty acids were produced under the increasing N application rate treatments than under the control. Moreover, increasing the N application rate generally significantly increased the yields of individual fatty acids as well. Nevertheless, the increased seed oil content and altered fatty acid composition did not affect seed germination traits, as the seed germination potential and rate showed no obvious change among treatments or the control. The height and size of the tobacco plants also increased with the increasing N application rate, which would be beneficial for increasing biomass production for bioenergy. This study shows for the first time the feasibility of increasing the seed and oil yields and modifying the fatty acid composition of tobacco plants by increasing N addition.
Cui-ping Hua, Zhong-kui Xie, Zhi-jiang Wu, Yu-bao Zhang, Zhi-hong Guo, Yang Qiu, Le Wang, and Ya-jun Wang
The autotoxicity of root exudates and the change of rhizosphere soil microbes are two important factors that affect the quality and yield of Lanzhou lily (Lilium davidii var. unicolor). Phthalic acid (PA) is a major autotoxin of the root exudates in Lanzhou lily. In this study, we treated plants with different concentrations of PA from the Lanzhou lily root exudates and then analyzed the effects of autotoxins on fresh weight, shoot height, root length, and Oxygen Radical Absorbance Capacity in root. The diversity of soil fungi in Lanzhou lily soil was analyzed using MiSeq. The results showed that PA induced oxidative stress and oxidative damage of Lanzhou lily roots, improved the level of the membrane lipid peroxidation, reduced the content of antioxidant defense enzyme activity and the nonenzymatic antioxidant, and eventually inhibited the growth of the Lanzhou lily. We found that continuous cropping of Lanzhou lily resulted in an increase in fungal pathogens, such as Fusarium oxysporum in the soil, and reduced the size of plant-beneficial bacteria populations. The results in this study indicate that continuous cropping would damage the regular growth of Lanzhou lily.