One of the major problem in the cultivation of sugar beets is continuous cropping obstacle in China. In order to evaluate the effects of continuous cropping year on the photosynthetic performance, dry matter accumulation, and distribution of sugar beet, this study was conducted in the 2020–2021 crop season at the Agriculture and Forestry Sciences of Ulanqab, Inner Mongolia. A split plot system arrangement with three replications was set up to carry out the field testing. The main plots had five planting years, with the a first cropping of each growing season serving as the control (CK) and four continuous cropping treatments for one, two, three, and four years (designated as C1, C2, C3, and C4, respectively). The subplot consisted of two fertilization treatments designated as 0 kg ha−1 bio-organic fertilization (N) and 6000 kg ha−1 bio-organic fertilization (Y). The findings demonstrated that the continuous cropping impeded sugar beet photosynthesis as well as the accumulation and dispersion of the dry matter in leaf, petiole, and root. The intercellular CO2 concentration (Ci), transpiration rate (Tr), stomatal conductance (Gs), net photosynthetic rate (Pn), and SPAD value were dramatically dropped as the number of continuous cropping years increased under the crop. Compared with CK, the SPAD value, Pn, Ci, Tr, Gs of continuous cropping treatments were significantly reduced by an average of 10.09–48.21%, 14.60–43.19%, 12.00–42.86%, 7.77–43.83%, 9.61–37.68%, respectively. The dry matter accumulation of leaf, petiole, root, and the whole plant were also reduced by 11.86–49.61%, 9.58–44.77%, 17.26–53.76%, and 10.62–49.79%, respectively. With the increasing of continuous cropping year, the growth of sugar beet was significantly inhibited. Study revealed that continuous cropping had an impact on the distribution of dry matter accumulation of sugar beet; it considerably raised the dry matter ratio above ground, lowered the dry matter ratio below ground, and prevented dry matter from moving from aboveground towards root, whitch caused a decline in sugar beet root production and disturbed the root shoot ratio. Compared with CK, the root shoot ratio significantly decreased by 3.62–19.76%. Under continuous cropping stystem, the application of bio-organic fertilizer had an effect on promoting the photosynthesis of sugar beet, and regulating the distribution and transport of dry matter. The effects of bio-organic fertilizer were significantly under continuous cropping for 1–2 years. Compared with C1N and C2N, the Pn, Ci, Tr, Gs of C1Y and C2Y were significantly increased by 12.79–22.50%, 14.76–16.47%, 4.76–13.08%, 8.51–12.70%, and 13.69–18.91%, 12.17–14.60%, 5.71–15.14%, 7.58–15.41%, respectively. Dry matter accumulation of leaf, petiole, root, whole plant were significantly increased by 8.32–16.18%, 10.80–13.33%, 14.93–20.13%, 14.12–15.43%, and 10.65–15.32%, 6.58–15.63%, 15.37–20.94%, 12.68–16.85%, respectively. Nonetheless, the root shoot ratio increased by 4.58–8.56% and 4.52–7.35%. Above all, Under continuous cropping conditions, the application of 6000 kg ha−1 bio-organic fertilizer could effectively promote the photosynthesis of sugar beet, and better regulate the distribution and transport of dry matter of sugar beet. These results can provide scientific basis for bio-organic fertilizer to alleviate the problem of sugar beet continuous cropping.
To explore the light intensity suitable for the growth of purple leaf lettuce seedlings in plant factories and greenhouses, the effects of light intensity of 6000, 12,000, 18,000, 24,000, and 30,000 lx on growth morphology, nutritional quality, photosynthetic pigment, and photosynthetic characteristics of purple leaf lettuce seedlings were studied with ‘Beizisheng 3’ as the experimental material under the condition of white light quality unchanged. The results showed that under a light intensity of 30,000 lx, purple leaf lettuce seedlings grew well, and the biomass, chlorophyll a content, chlorophyll b content, carotenoid content, total chlorophyll, soluble protein content, soluble sugar content, vitamin C content, anthocyanin content, net photosynthetic rate, transpiration rate, and stomatal conductance were the largest, while the nitrate content and intercellular CO2 concentration were the lowest. However, chlorophyll b content, carotenoid content, soluble protein content, and transpiration rate had no significant difference compared with those under 24000 lx light intensity, and the plant height was the highest under 24,000 lx light intensity. Under the condition of white light quality, the most suitable light intensity for the growth of purple leaf lettuce seedlings is 30,000 lx.
研究旨在对2001-2021年呼伦贝尔农垦集团各农牧场的生态净初级生产力(Net ecosystem productivity,NEP)进行评估,为开展农田生态系统的碳源/汇分析提供技术参考.研究基于遥感、气象等数据计算呼伦贝尔农垦集团各农牧场的NEP,并结合Sen趋势线分析法、Hurst指数、变异系数法、偏相关分析法对NEP的变化趋势和气候响应情况进行分析.研究表明:呼伦贝尔农垦集团的年平均NEP为221.1 gC/(m·a),从大兴安岭向两麓递减分布;研究期内NEP主要呈现显著或极显著的增加趋势,但Hurst指数分析表明,大部分农牧场未来NEP的变化与之前呈负相关,即减少趋势;呼伦贝尔农垦集团的NEP与降水呈极显著正相关,而与气温的相关程度不大.建议呼伦贝尔农垦集团加强固碳能力高的耕作方式的推广力度,防止农田生态系统的固碳能力下降,同时加强农业灌溉及人工影响天气能力建设,降低农田干旱灾害的发生风险及影响.
水分、盐碱、温度和重金属等非生物逆境因子胁迫烟草的生长发育,研究发现外源物质在烟草逆境缓解中扮演十分重要的角色.文章归纳了非生物胁迫对烟草生长的不利影响,总结了外源物质缓解非生物胁迫的作用途径,分析了外源物质施用的最佳浓度,指出施用外源物质可能对烟草产生的不利影响,并指出了多种外源物质复配效果优于单一外援物质影响,同时展望了今后烟草非生物逆境研究的前景,以期为挖掘和应用新的外源物质以及阐明其缓解逆境影响的调控机制提供理论依据.
为明确干物质积累、转运与产量性状对密度与行距差异的响应机制,促进棉花品种推广与种植技术革新.以'中棉所641'为试验材料,采用76 cm等行(SP)与(66 cm+10 cm)宽窄行(DP)种植模式,设3个种植密度,分别为Ⅰ:低密度12万株/hm2;Ⅱ:中密度18万株/hm2;Ⅲ:高密度24万株/hm2.应用Logisitic曲线方程,进行数据分析.SP Ⅱ处理棉花△T(生物量快速积累持续期)在2020、2021年分别为54.7 d和55.6 d.其2020、2021年营养器官干物质快速积累持续时间分别为33.3天和38天,最大积累速率均为1.13g/(株·d),高于其他处理.2020、2021年生殖器官干物质快速积累持续时间分别为35.26d、25.79d,最大积累速率均为1.05 g/(株·d).2 a试验数据均显示,SPⅡ处理棉花花前、花后单株干物质转化量最高.2020、2021年SP Ⅱ处理籽棉产量分别为5359.48、5151.00 kg/hm2,单株成铃数均为6.12个.产量对行距差异的响应程度强于密度差异.18万株/hm2等行距种植模式有利于棉花充分利用光热资源,促进干物质积累与转运,提高籽棉产量.
