MdBT2 regulates nitrogen-mediated cuticular wax biosynthesis via a MdMYB106-MdCER2L1 signalling pathway in apple.

Cuticular waxes play important roles in plant development and the interaction between plants and their environment. Researches on wax biosynthetic pathways have been reported in several plant species. Also, wax formation is closely related to environmental condition.

[Effects of large-grained activated humic acid fertilizer on soil aggregates and organic carbon in apple orchard soil].

The new large-grained activated humic acid fertilizer (LAF) can significantly reduce the amount of chemical fertilizer application and stable fruit yield. Understanding its impacts on soil aggregates and organic carbon is an important basis for revealing its role in driving soil structure of apple orchard. There were four LAF treatments: LAF (full fertilization, fertilization period and mass ratio (the same below), germination stage: fruit expansion stage: maturity stage=3:4:3), LAF (full fertilization, germination stage: fruit expansion stage: maturity stage=2:3:5), LAF (fertilizer application reduction by 1/4, germination stage: fruit expansion stage: maturity stage=2:3:5), LAF (fertilizer application reduction by 1/3, germination stage: fruit expansion stage: maturity stage=2:3:5); with no fertilization as control (CK).

[Effects of different integration of water and fertilizer modes on the absorption and utilization of nitrogen fertilizer and fruit yield and quality of apple trees].

We examined nitrogen use efficiency of N-urea of 15-year-old 'Gala' apple trees by broadcast fertilization (T), nitrogen fertilization with drip irrigation (T) and nitrogen fertilization with subsurface irrigation (T), to further improve the water and fertilizer integration technology for apple orchard and to improve nitrogen utilization efficiency. The results showed that leaf area, chlorophyll, and leaf nitrogen content of leaves were significantly higher in T treatment than those in T and T treatments. Soil mineral nitrogen content (20-40 cm) in each period followed the order of T>T>T, while that in 0-20 cm followed an order of T>T>T.

[Effects of potassium levels on translocation of C-photoassimilates to fruit in 'Fuji' apple during fruit expanding period].

A field experiment was carried out in a six-year old 'Fuji'3/M26/Malus hupehensis Rehd. apple with the C tracer method to examine the changes of chlorophyll fluorescence parameters, photosynthetic characteristics of leaf, sugar transporter gene expression, C assimilation capability and the characteristics of translocation and distribution of C-photoassimilates to fruit under different levels of potassium addition (KO 0, 0.5%, 1.

[Effects of NaWO on N absorption and utilization,C accumulation of apple seedling, and fruit quality].

Pot culture and field experiments were carried out with one-year-old apple rootstock M9T337 seedlings and five-year-old 'Yanfu3'/SH6/M. hupehensis Rehd. as test materials respectively.

[Effects of potassium supply on the growth, photosynthesis and N and C absorption and utilization of M9T337 seedling].

Hydroponic experiment was carried out on M9T337 seedlings using N and C isotope tracer technology to study the effects of different potassium supply levels (K, K, K, K and K were equivalent to 0, 3, 6, 9 and 12 mmol·L, respectively) on the growth, photosynthetic characteristics and N and C absorption and utilization of M9T337 seedlings. The results showed that dry mass, root length, root surface area, number of tips and root activity of M9T337 seedlings under the K level were significantly higher than those under other levels. The net photosynthetic rate (P) of leaves increased at low K concentration and then decreased with the increases of potassium supply level, and reached the maximum value at K treatment (15.

[Effects of exogenous ABA on translocation of photosynthate to fruit of Fuji apple during late stage of fruit rapid-swelling.].

To clarify the effects and underlying mechanism of ABA on sugar accumulation in apple fruits, C trace technique was used to examined the effects of different ABA levels (0, 50, 100 and 150 mg·L) and fluoridone (ABA biosynthesis inhibitor) on translocation of photosynthate to fruit during late stage of fruit rapid-swelling in five-year-old 'Yanfu3'/M26/Malus hupehensis Rehd. The results showed that the activities of related enzyme in sugar metabolism, the relative expression of sucrose transporter gene MdSUT1, MdSUT2.2 and sorbitol transporter gene MdSOT3 tended to increase first and then decrease with increasing ABA concentration, with a peak in 100 mg·LABA treatment.

[Effects of nitrogen application levels on translocation and distribution of C-photosynthate and N to fruit from leaves of apple tree].

A field experiment was carried out in a six-year old 'Fuji3'/M26/Malus hupehensis Rehd. apple with N and C labeled tracers, to understand C assimilation capability and the characteristics of translocation and distribution of C-photosynthate and N to fruit under different nitrogen application levels (urea 0%, 0.6%, 1.

[Effects of split combined application of organic-inorganic fertilizers on plant growth, N absorption, utilization and loss of Gala apple tree].

Fifteen-year-old 'Gala'/M. hupehensis Rehd. trees and N trace technique were used to explore the effects of split combined application of organic-inorganic fertilizers on plant growth, N absorption, utilization and loss.

Dynamics of growth and nitrogen accumulation and utilization of young apple trees.

Taking 6-year-old Yanfu3/SH6/Malus hupehensis Rehd. as the test material, the dynamics of plant growth and nitrogen (N) accumulation under seven periods from germination stage to fruit maturity stage were examined by destructive analysis. The absorption, utilization, and distribution of fertilizer N were studied by N isotope tracer technique to clarify the N accumulation dynamics of apple trees and the maximum efficiency period of fertilizer N, and to provide theoretical basis for scientific application of N fertilizer.

[Effects of different phosphorus application rates on growth, N-urea absorption, and utilization characteristics of pear rootstocks].

Three kinds of potted one-year-old pear rootstocks (Pyrus calleryana, P. pashia, and P. xerophila) and N trace technique were used to examine the effects of different phosphorus application rates (P, P, P, P and P equivalent to 0, 50, 100, 150 and 200 kg·hm PO, respectively) on plant growth and the characteristics of N-urea absorption and utilization.

[Nitrogen application technology in dwarfed apple trees.].

N trace technique was used to explore the characteristics of N-urea absorption, utilization, loss and fruit quality of eight-year-old 'Yanfu3'/M26/Malus hupehensis Rehd. seedlings. There were three different nitrogen fertilization treatments: one-time nitrogen application in spring (1), two times nitrogen application (2), the intensive technique of nitrogen application with several times application and reduction in amount (3).

[Effects of controlled-release nitrogen fertilizer and bag-controlled release fertilizer on utilization of N-urea in 'Orin' apple and its accumulation in soil].

Taking a six-year old 'Orin' apple tree plantation ('Orin'/SH6/ Malus micromalus Makino) as test material, the effects of common urea treatment (CU), bag-controlled release ferti-lizers treatment (BCRF) and controlled-release nitrogen fertilizer treatment (CRNF) on N-urea absorption, utilization, loss and accumulation dynamics of nitrogen content in 0-80 cm soil layer were investigated by N labeled tracer method. The results showed that compared with CU treatment, both CRNF and BCRF treatments increased the inorganic nitrogen content in soil at the late stage of apple growth, the leaf SPAD value, leaf nitrogen content, net photosynthetic rate and N derived from fertilizer (Ndff value) of different organs at fruit maturity stage, with CRNF showing stronger effects than BCRF. The amount of N residue in 0-40 cm soil layer showed a decreasing trend in different phenological stages.

[Effects of different fulvic acid application rates on fruit yield, quality and fate of N-urea in 'Red General' apple].

To explore the effects of different fulvic acid application rates on N-urea absorption, utilization, residue amount, loss and fruit yield and quality, fifteen-year-old 'Red General'/ Malus micromalus Makino was selected as experiment material by using the N-labeled tracer technique. Five treatments were established: single urea (CK), combination of urea and fulvic acid with varied rates (NF, NF, NF and NF represented 75, 150, 300 and 450 kg·hm fulvic acid application rates, respectively). The main results were as follows: the N derived from fertilizer (Ndff) in root, one-year-old branch and leaf were displayed with an order of NF>NF>NF>NF>CK at the fruit maturity stage, and significant difference was observed in Ndff value among the five treatments.

[Effects of different potassium levels on growth and NO uptake and utilization of Malus hupehensis seedlings].

In order to explore the effects of potassium fertilizer on the absorption and utilization of nitrogen fertilizer, and provide theoretical basis for scientific fertilization in apple orchard, Malus hupehensis seedlings were used to study the effects of different potassium levels (K, K, K, K, K, K, and K equivalent to 0, 2, 4, 6, 8, 10, and 12 mmol·L K, respectively) on growth and NO uptake and utilization using the track technology of N and non-damage microtest technique. The results showed that root vigor, nitrate reductase activity and root morphological index of seedlings in K treatment were significantly higher than those in the other treatments. The N derived from fertilizer (Ndff) in different organs of M.

[Effects of different nitrogen application rates on N-urea absorption, utilization, loss and fruit yield and quality of dwarf apple].

Seven-year-old 'Yanfu3'/M/M. hupehensis Rehd. seedlings and N trace technique were used to explore the characteristics of N-urea absorption, utilization, loss and fruit yield and quality under different nitrogen application rates (N, N and N).

[Effects of nitrogen-supply levels on leaf senescence and characteristics of distribution and utilization of C and N in Fuji 3 apple grafted on different stocks].

Two-year-old potted Fuji 3 apple trees on different rootstocks [Fuji 3/M. micromalus Makin (joe), Fuji 3/M7 (semi-dwarf) and Fuji 3/M26/M. micromalus Makin (dwarf)] were used to study leaf morphology and photosynthesis and the characteristics of distribution and utilization of C and N at different nitrogen supply levels (0N, 25%N and 100%N, the N content in 100% N treatment was the same as that in Hoagland complete nutrient solution) under sand culture condition.

[Fate of fertilizer nitrogen and soil nitrogen pool budget of Fuji apple from germination stage to new shoot growing stage].

N trace technique were used to explore the fertilizer nitrogen (N) absorption and utilization, soil residue and soil nitrogen pool budget under different nitrogen fertilization levels (0, 50, 100, 150, 200, 250 kg·hm) for five-year-old 'Yanfu 3'/SH6/M. hupehensis Rehd. from germination stage to new shoot growing stage.

[Effects of nitrate nitrogen supply on the growth, photosynthetic characteristics and N absorption, utilization of Malus hupehensis seedlings].

To explore the effects of different nitrate nitrogen levels (N, N, N, N and N were equivalent to 0, 2.5, 5, 10, 20 mmol·LNO -N, respectively) on the growth, photosynthetic characteristics and N absorption, utilization and distribution, Malus hupehensis seedlings were grown in cultural liquid Hoagland by using the N-labeled tracer method. The results showed that the leaf chlorophyll content, leaf area and dry mass in different organs were the highest in N treatment.

Improving the Accuracy of the Hyperspectral Model for Apple Canopy Water Content Prediction using the Equidistant Sampling Method.

The influence of the equidistant sampling method was explored in a hyperspectral model for the accurate prediction of the water content of apple tree canopy. The relationship between spectral reflectance and water content was explored using the sample partition methods of equidistant sampling and random sampling, and a stepwise regression model of the apple canopy water content was established. The results showed that the random sampling model was Y = 0.

[Response of water status indicators in apple saplings to drought stress under shelter from rain.].

The main tree water status indicators which sensitively responded to drought stress and related to tree water balance were investigated in treatment of progressive decrease of soil water potential under shelter from rain. The results showed that stem maximum daily shrinkage (MDS) and midday stem water potential (Ψ) were most sensitive to drought stress among all the water status indicators. MDS not only significantly responded to reference crop evapotranspiration (ET), but also was sensitive to soil drought stress.

[Hyperspectral Estimation of Apple Tree Canopy LAI Based on SVM and RF Regression].

Leaf area index (LAI) is the dynamic index of crop population size. Hyperspectral technology can be used to estimate apple canopy LAI rapidly and nondestructively. It can be provide a reference for monitoring the tree growing and yield estimation.

[Research progress of cover crop in Chinese orchard].

Grass growing in orchard is implemented in most fruit cultivation advanced countries, but only China carries out grass weeding. To effectively resolve the puzzle on harmful or beneficial effect on fruit production imparted by grass growing, and promote grass growing management in orchard in China, more and more domestic research was reported in recent years. Combined the results of our research and domestic related research, we reviewed the latest research progress about the effect of growing grass on soil, microclimate, fruit tree diseases and insect pests, tree growth and fruit quali- ty, etc.