Search

The objective of this study was to investigate the root growth compensatory effects and cotton yield under drought stress. The results indicate that the root dry weight, boll weight, and cotton yield increased in both the drought-resistant cultivar (CCRI-45) and the drought-sensitive cultivar (CCRI-60). Compensation effects were exhibited under the three-day drought stress treatment at a soil relative water content (SRWC) of 60% and 45% during the seedling stage, and flowering and boll-forming stage over two years. The yield of the drought-resistant cultivar (CCRI-45) was higher than the control, however, following the six-day 45% SRWC drought treatments, the yield of the drought-sensitive cultivar (CCRI-60) was lower than the control. The soluble sugar content, proline content, superoxide dismutase (SOD) activity, and peroxidase (POD) activity of the roots increased under drought stress and then decreased after re-watering, although the values remained higher than those of the controls for a short period. These physiological measures may represent stress reactions and thus may not indicate factors that result in compensation effects. However, catalase (CAT) activity and gibberellic acid (GA) content of the roots decreased under drought stress. After re-watering, the CAT activity and the GA content increased and were significantly higher than those of the controls under the six-day 60% SRWC and 45% SRWC drought treatments. The abscisic acid (ABA) content of the roots increased under drought stress. After re-watering, the ABA content decreased to a lower level under the three and six-day 60% SRWC and 45% SRWC drought treatments than in the controls. According to an analysis of various indicators, the interaction between ABA and GA signals may play an important role in root growth compensatory effects. In summary, the results demonstrate that moderate drought stress is beneficial to root growth and yield. This conclusion is of great significance to improving our understanding of the maximum utilization of limited water resources. [ABSTRACT FROM AUTHOR]

• Condylomata acuminata occurred in the urethra is uncommon. • ALA-PDT combined with wart curettage treatment were effective in intractable urethral CA patient. • Wart curettage treatment before ALA-PDT can improve the therapeutic effect of PDT and reduce side-effects. Condylomata acuminata (CA) is caused by human papillomavirus (HPV). It is one of the most common sexually transmitted diseases (STD). The lesions mainly occur in the external genitalia and perianal areas, rarely involves in urethral and usually localized at the distal 3 cm of the urethral orifice. Because of the special anatomical site, treating urethral CA is challenging and it has high recurrence rate after treatment. 5-aminolevulinic acid photodynamic therapy (ALA-PDT) can successfully treat urethral CA, however, the experience of using ALA-PDT combined with wart curettage to treat intractable urethral CA is still very limited. In here, we reported an intractable urethral CA case with effective remission after receiving combination therapy. Wart curettage combine with ALA-PDT is an expeditious, economical, and well-tolerated treatment method. [ABSTRACT FROM AUTHOR]

Allocation of newly formed biomass towards plant organs is a key determinant of plant performance that is affected by agronomic practices such as plant population density and use of growth regulators. Here we quantified biomass allocation of intercropped cotton ( Gossypium hirsutum ) growing at two population densities (3.0 and 7.5 plants m −2 ) and with or without application of the growth regulator mepiquat chloride (MC) in three consecutive years. The beta growth function was used to quantitatively characterize the dynamics of biomass partitioning. Compared to low density, high density increased daily growth rate and final above-ground dry matter, but decreased allocation to fruits. Application of MC did not affect dry matter accumulation but increased allocation to fruits by 22%. The parameters of the beta growth function have a clear biological interpretation, providing a useful quantitative characterization of the effect of management on dry matter allocation in cotton. The function may also be used to model organ-specific daily assimilate partitioning as a component in models of plant growth and crop production with the consideration of discussed caveats. [ABSTRACT FROM AUTHOR]

Trees are the dominant species in agroforestry systems, profoundly affecting the performance of understory crops. Proximity to trees is a key factor in crop performance, but rather little information is available on the spatial distribution of yield and yield components of crop species under the influence of trees in agroforestry systems. Also, little information is available on how crop density may be exploited to optimize the yield in such systems. Here we studied the performance of cotton in jujube/cotton agroforestry. Field experiments were conducted in 2012 and 2013 in Hetian, Xinjiang, China. Cotton was grown at a row distance of 60 cm in three densities, 13.5, 18.0 and 22.5 plants m −2 in six m wide paths between tree lines in a jujube plantation. Plant density affected both cotton aboveground dry matter and yield significantly. The highest yield was attained at the intermediate density of 18.0 plants m −2 (20.0 plants m −2 corresponding in sole cotton), lower than the optimal density in sole cotton (25.0 plants m −2 ). Yield at the lower density was constrained by the low number of bolls per m 2 as a direct consequence of the low density, whereas at the high plant density yield was constrained by a lower allocation of assimilates to cotton seed and lint, as a consequence of intraspecific and interspecific competitions. There were strong gradients in yield and yield components in relation to the distance from the tree rows. Leaf area and total dry matter of cotton in rows close to the tree lines were reduced, especially in the rows next to the trees. Moreover, biomass allocation to cotton fruits was reduced in these rows. Competitive influences from the trees on cotton performance extended two rows deep in a six-year old jujube stand, and even three rows deep in a seven-year old stand. Shading effects on cotton yield were compensated by increasing plant density as a result of greater boll numbers per unit ground area. Data from this study help guide the design of optimal plant density of cotton in jujube plantations and give insight in the spatial distribution and dynamics of competitive effects in agroforestry systems in general. [ABSTRACT FROM AUTHOR]

One of the key decisions in crop production is the choice of row distance and plant density. The choice of these planting pattern parameters is especially challenging in heterogeneous systems, such as systems containing alternating strips. Here we use functional–structural plant modelling to address the problem of identifying optimal row distances and plant density in a heterogeneous crop system. We compare radiation capture in sole cotton and relay strip cotton, remaining after harvest of wheat from a wheat–cotton relay strip intercrop. We compare light interception in the two systems under different scenarios of row distance and plant density. Light interception calculations with the functional–structural plant model were evaluated using field observations. Light interception by cotton was mainly determined by row distances and to a lesser extent by plant density. Light interception was reduced by the gaps between the strips in strip cotton. Plant density (per unit area of the whole system) providing maximum light interception was lower in relay strip cotton than in normal cotton. Plastic responses of cotton to canopy heterogeneity, accounted for in the model, did not result in full radiation capture in strip cotton. The gaps between the rows in strip cotton allowed light penetration to deeper canopy layers relevant for the reduction of fruit abortion rate. We conclude that relay strip cotton cannot attain the same light interception as sole cotton, due to the gaps between the strips. Increasing plant density was insufficient to bridge the gap. Thus, the maximum light interception in strip cotton is lower than in sole cotton, and is achieved at a lower overall plant density. FSP modelling provided a suitable tool to identify row distance and plant densities providing high light interception in a heterogeneous canopy. [ABSTRACT FROM AUTHOR]

Cotton yield is greatly improved by moderately increasing plant density and modifying the cotton plants to have a compact structure, which is also required by the increasing demand for mechanized harvest. However, in cotton strip intercropped with wheat, only limited knowledge on yield response to plant density and plant growth regulator i.e. mepiquat chloride (MC) exists. Here we quantified MC and plant density effects on cotton yield components and quality in wheat–cotton relay intercropping by three field experiments in 2010–2012 in Anyang, China. Four plant densities and four MC treatments were applied in different times and dosages. Lint yield significantly increased 40.7% when plant density increased from 3.0 to 7.5 plants m −2 , and enhanced 7.9% by applying MC four times compared to MC free control. High densities increased the number of bolls per m 2 but decreased single boll weight. Conversely, applying MC generally slightly decreased number of bolls, with the exception of a significant increase by applying MC four times, and increased boll weight. Lint percentage was decreased by applying MC. The yearly climate significantly impacted the effects of applying MC and plant density. Application of MC did not significantly affect cotton fiber length and micronaire, but increased fiber strength. Applying MC in combination with increasing plant density led to harvestable bolls to be located more at low and middle positions on the plant. The increase of boll weight by applying MC was partly resulted from the optimal distribution of harvestable bolls within the canopy. The results help farmers to optimize plant density and MC application in the intercropped cotton. [ABSTRACT FROM AUTHOR]

Highlights: [•] Plant growth regulator mepiquat chloride (MC) significantly reduced plant height and length of branches. [•] Increasing plant density significantly increased crop light use efficiency, especially during the reproductive phase. [•] At high plant densities, MC improved plant architecture, resulting in a higher light use efficiency and yield. [Copyright &y& Elsevier]