scholarly journals Effect of Trunk Size on the Relationship between Drought Stress and First-Flush Flower Number in Meiwa Kumquat

2019 ◽  
Vol 57 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Naoto IWASAKI ◽  
Shinichiro HIRATSUKA
HortScience ◽  
2012 ◽  
Vol 47 (8) ◽  
pp. 1050-1055 ◽  
Author(s):  
Xiaoya Cai ◽  
Terri Starman ◽  
Genhua Niu ◽  
Charles Hall ◽  
Leonardo Lombardini

A greenhouse study was conducted to evaluate the response of four garden roses (Rosa ×hybrid L.), ‘RADrazz’, ‘Belinda’s Dream’, ‘Old Blush’, and ‘Marie Pavie’, to drought stress. Plants grown in containers were subjected to two watering treatments, well-irrigated [water as needed: ≈35% substrate moisture content (SMC) at re-watering] and cyclic drought stress (withholding irrigation until plants exhibit incipient wilting: ≈10% SMC, then re-watering to field capacity for subsequent dry down). Shoot growth and flower number were reduced in the drought treatment compared with the well-irrigated plants in all cultivars with least reduction in ‘RADrazz’. Drought stress reduced root growth in ‘Belinda’s Dream’ and ‘Marie Pavie’, whereas there was no difference in root growth in ‘RADrazz’ and ‘Old Blush’. Decreased SMC induced reduction in net photosynthetic rate (Pn), stomatal conductance (gS), transpiration rate (E), and midday leaf water potential (ψ). Leaf water use efficiency (WUE) increased as SMC decreased in all cultivars. However, the relationship between these physiological parameters and SMC differed among the cultivars. At SMC between 10% and 20%, ‘RADrazz’ had higher Pn, gS, E, and WUE compared with the other three cultivars. Therefore, ‘RADrazz’ was the most drought-tolerant during container production among the cultivars investigated. With lower gas exchange rates and greater reduction in flower number at low SMC, ‘Marie Pavie’ was less drought-tolerant compared with the other three cultivars.


HortScience ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 292-294 ◽  
Author(s):  
Meriam Karlsson ◽  
Jeffrey Werner

The rate of leaf unfolding for Cyclamen persicum Mill. was determined at 8 to 24 °C. Temperature treatments started 9 weeks from seeding and after 8 weeks all plants were moved to 16 °C. The cultivars Miracle Salmon, Miracle Scarlet, and Miracle White produced leaves at a similar rate. The relationship of (leaves/d) = - 0.01727 - 0.02284 * °C + 0.005238 * (°C)2 - 0.000162 * (°C)3 (R2 = 0.99) best described the leaf unfolding rate in response to temperature. The maximum leaf unfolding rate was estimated to 0.329 leaves/day at 19.1 °C. Flower buds (2 mm diameter) developed within 60 days from the start of temperature treatments except at 8 °C. Thirty-five additional days at 16 °C were required for cyclamen initially grown at 8 °C for 8 weeks to produce flower buds. Despite similar conditions during bud development, flowering was delayed 14 to 18 days for plants initially grown at 24 °C compared to those grown at 12 to 20 °C. Plants initially at 8 °C did not flower within 70 days at 16 °C. Leaf and flower numbers at first open flower increased as initial temperature increased from 12 to 24 °C while dry weight and height only increased to 20 °C. No correlation between leaf unfolding and rate of flowering or flower number was detected. Recommendations for 20 °C during early cyclamen growth can be expected to support rapid rates of leaf unfolding and development, and large flower numbers.


2021 ◽  
Author(s):  
Ming-zhu Jia ◽  
Ling-yun Liu ◽  
Chen Geng ◽  
Chun-peng Song ◽  
Jing Jiang

AbstractIt is known that the transcription factor SPEECHLESS (SPCH) drives entry of epidermal cells into stomatal lineage, and that the activation of subtilisin-like protease SDD1 reduces stomatal density and cluster on the epidermis. However, there is still a big gap in our understanding of the relationship between stomatal development and the establishment of stomatal density and pattern, especially during drought. Interestingly, 1-aminocyclopropane-1-carboxylic acid (ACC) not only promotes stomatal development, but also is involved in the establishment of stomatal density and pattern. ACC generation comes from the activity of ACC synthase (ACS), while ACS activity could be mediated by drought. This work showed that the Arabidopsis SPCH activated ACS2/6 expression and ACC-dependent stomatal generation with an increase of stomatal density and cluster under drought conditions; and the possible mechanisms were that ACC-induced Ca2+ shortage in stomatal lineage reduced the inhibition of the transcription factor GT-2 Like 1 (GTL1) on SDD1 expression. These suggest that ACS2/6-dependent ACC accumulation integrated stomatal development with the establishment of stomatal density and pattern by mediating Ca2+ levels in stomatal lineage cells on the leaf epidermis, and this integration is directly related to the growth or survival of plants under escalated drought stress.HighlightACC synthase ACS2/6 activation integrated stomatal individual development with space setting between stomata by mediating Ca2+ levels in stomatal lineage on the leaf epidermis in response to drought.


2015 ◽  
Vol 60 (4) ◽  
pp. 407-417
Author(s):  
Seyed Mirtaheri ◽  
Farzad Paknejad ◽  
Marieh Behdad

In order to evaluate the relationship between yield and some relevant traits and estimation of the most effective traits on grain yield, a split-plot experiment based on completely randomized block design with four replications was carried out in 2006-2007 in the research field of Islamic Azad University of Karaj. The irrigation schemes scheduled as main plots included the following: (T1) 40% moisture depletion throughout the growing season (control); (T2) 60% moisture depletion throughout the growing season; (T3) 80% moisture depletion throughout the growing season; (T4) no irrigation during the stem elongation stage and continuing with adequate irrigation to the end of the growing season; (T5) no irrigation from the stem elongation stage to the end of the growing season; (T6) no irrigation at flowering and continuing with adequate irrigation to the end of the growing season; (T7) no irrigation from flowering to the end of the growing season; and (T8) no irrigation from the milk stage to the end of the growing season; and 2 wheat cultivars [Marvdasht (V1), Chamran (V2)] as sub-plots. According to the results of simple correlation, the grain yield exhibited the most positive correlation with biomass (0.877), number of infertile spikelets (0.876) and harvest index (0.855). The results of step-wise regression showed that, in the absence of drought stress, biomass and harvest index had respectively the most important effects on the grain yield but both exhibited different results under drought stress. Path analysis results showed that the most important effect on the grain yield in the total tested treatments was related to the biomass, justifying a total of 87% of grain yield variations, 72% of which is the direct effect of this trait on grain yield.


2020 ◽  
Vol 180 ◽  
pp. 174-184
Author(s):  
Shuangcheng Tang ◽  
Zhonghua Jia ◽  
Qing Xu ◽  
Wan Luo ◽  
Zhengqing Shan

2007 ◽  
Vol 55 (3) ◽  
pp. 71-77 ◽  
Author(s):  
L.-H. Kim ◽  
S.-M. Jeong ◽  
S.-O. Ko

Recently the Ministry of Environment in Korea has developed the total maximum daily load program in accordance with the target pollutant and its concentration goal on four major large rivers. Since the program is largely related to regional development, nonpoint source control is both important and topical. Of the various nonpoint sources, highways are stormwater intensive land uses since they are impervious and have high pollutant mass emissions from vehicular activity. The event mean concentration (EMC) is useful in estimating the loadings to receiving water bodies. However, the EMC does not provide information on the time varying changes in pollutant concentration or mass emissions, which are often important for best management practice development, or understanding shock loads. Therefore, in this study a new concept, the dynamic EMC determination method, will be introduced to clearly verify the relationship between EMC and the first flush effect. Three monitoring sites in Daejeon metropolitan city areas were equipped with an automatic rainfall gauge and a flow meter for accumulating the data such as rainfall and runoff flow. The dynamic EMC method was applied to more than 17 events, and the improved first flush criteria were determined on the ranges of storm duration and accumulated rainfall.


2018 ◽  
Vol 9 (24) ◽  
pp. 10-21
Author(s):  
Seyed Javad Talebzadeh1 ◽  
Hashem Hadi ◽  
Reza Amirnia ◽  
Mehdi Tajbakhsh ◽  
Mohammad Rezaei Morad Ali ◽  
...  

2021 ◽  
Author(s):  
Qingmei Guan ◽  
Xuewei Li ◽  
Shuang-Xi Zhou ◽  
Liyuan Lu ◽  
Huan Dang ◽  
...  

SUMOylation is involved in various aspects of plant biology, including drought stress. However, the relationship between SUMOylation and drought stress tolerance is complex; whether SUMOylation has a crosstalk with ubiquitination in response to drought stress remains largely unclear. In this study, we found that both increased and decreased SUMOylation led to increased survival of apple (Malus × domestica) under drought stress: both transgenic MdSUMO2A overexpressing (OE) plants and MdSUMO2 RNAi plants exhibited enhanced drought tolerance. We further confirmed that MdDREB2A is one of the MdSUMO2 targets. Both transgenic MdDREB2A OE and MdDREB2AK192R OE plants (which lacked the key site of SUMOylation by MdSUMO2A) were more drought tolerant than wild-type plants. However, MdDREB2AK192R OE plants had a much higher survival rate than MdDREB2A OE plants. We further showed SUMOylated MdDREB2A was conjugated with ubiquitin by MdRNF4 under drought stress, thereby triggering its protein degradation. In addition, MdRNF4 RNAi plants were more tolerant to drought stress. These results revealed the molecular mechanisms that underlie the relationship of SUMOylation with drought tolerance and provided evidence for the tight control of MdDREB2A accumulation under drought stress mediated by SUMOylation and ubiquitination.


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