The reason of chlorophyll reduction was deterioration of pigments in leaves from enzymatic conversion by chlorophyllase. Chlorophyllase continuously reacts during storage, causing chlorophyll in lettuces content to gradually decrease. However, there was no linear relationship found between the relative content of chlorophyll and root length, as shown in Table 1. To then, chlorophyll content loss was further analyzed. Changes in the loss rate of chlorophyll content with different root lengths is presented in Fig. 3. Gradual risings in the loss rate of chlorophyll content were found at all samples during storage. In the group of 3 cm, the loss rate of chlorophyll content was 27.3% at the end of storage, same as the group of the whole root length. The percentage of the loss amounted was maximum in the five groups. In the groups of 6 cm and 9 cm, the loss rates of chlorophyll content were 23% and 24%. In the group of 0 cm, the percentage of the loss amounted was minimal that was 20%. The reduction in chlorophyll is mainly related to chlorophyllase. After lettuce leaves the nutrient solution, retaining roots may not affect the activity or content of chlorophyllase. Therefore, whether to retain the lettuce roots will not affect the relative content of chlorophyll.Change of chromatic aberration with different root lengths at successive storage was shown in Fig. 4.Overall, gradual rises in chromatic aberrations were recorded throughout the storage in all cases. One of the reasons for the color change of the leaves is enzymatic browning. Generally, browning reaction is assumed to be a direct consequence of the action of oxidizing enzymes polyphenol oxidase  and peroxidase on phenolic substrates. O-quinones are produced by these reactions and can subsequently be converted to brown pigments by non enzyme-catalyzed reactions, which changes leaf color . Therefore, the increasing values of chromatic aberration due to the continuous browning reaction during storage. Fig. 4 showed that chromatic aberrations of the groups of retaining root were smaller than that of the group without root. In the group of 0 cm, the chromatic aberration was 8.7 NBS at the end of storage. It was maximum in the five groups. In the group of 3 cm and 6 cm, the chromatic aberrations were 7.8 NBS and 6.3 NBS, respectively. In the group of the whole root length, it was 6.9 NBS. In the group 9 cm, the chromatic aberration was 6.0 NBS that was minimal in the five groups. Retaining roots helps reduce the change of chromatic aberration. Ali et al. indicated that ascorbic acid  could inhibit PPO activity by reducing the degree of browning. Ascorbate peroxidase  can oxidize AA and inhibits the effects of AA.

The leaves and roots of lettuce have APX and PPO. But the APX activity of lettuce leaf was superior to that of root,hydroponic nft where produce more AA. Therefore, retaining root can increase AA content to inhibit PPO activity, which can reduce the degree of browning. The longer roots were retained, the more the AA will produce, and the greater the degree of browning will reduce. Therefore, the root length can be appropriately extended to reduce the color change of the hydroponic lettuce.Changes in the weight loss rate of lettuces are presented in Fig. 5. The weight loss rate of hydroponic lettuce increased with time increased. Transpiration and respiration of lettuce during storage will be conducted, which mainly leads to moisture loss. Therefore, the transpiration and respiration of lettuce made the rate of weightlessness continue to increase. Variations were found among the effects of different root lengths on the weight loss rate during the storage. In the group of 0 cm and 3 cm, the weight loss rates at the end of storage were all 1.8%, which were maximum in the five groups. In the group of 6 cm and 9 cm, the weight loss rates were 1.68% and 1.26%, respectively. In the group of the whole root length, the weight loss rate was 1.23% that was minimal in the five groups. The relationship between the weight loss rate of hydroponic lettuce and the root length was linear. The weight loss rate decreases as the length of root retention increases. Weight loss of leafy vegetables is mainly caused by moisture loss. Qiu et al.indicated that lettuce mainly absorbs water through roots. Samples in our study were stored in a high-humidity environment. Retaining roots makes lettuces absorb moisture from the high-humidity environment. The longer roots were retained, the more water will be absorbed, and the less weight will be lost. Therefore, longer roots were recommended to be retained during storage to reduce lettuce weight loss. Compared with hydroponic lettuce without root, the hydroponic lettuce which retained root has a better effect for retaining freshness. And it had the best effect of retaining freshness when the root length was 9 cm. Therefore, it was recommended to retained the root length of 9 cm when harvesting hydroponic lettuce. In this study, it was found that influenced indicators in others’ research may not be suitable for this experiment. For example, chlorophyll relative content could not reflect the effect of root length for retaining freshness. Therefore, it was necessary to choose influenced indicators that were suitable for this experiment. The packaging method may be different when harvesting with root. The future research direction is the packaging method of hydroponic lettuce which retained root.Species of lilies were used as ornamental plant for thousands of years. In the genera there are about 110 of wild species. Nevertheless the first hybrids derived from the 19th century. Classifications of lily species were set before several centenaries. DNA technology has helped to identify and distinguish the lily species and also detected their genetic diversity. In Lithuania, just naturally grows wild lily , other species are introduced. Identification of hybrids using DNA analysis was started at 20th century, nine decades. Natures of hybridswere confirmed analyzing DNA of parental forms and their offspring using RAPD method. Plant population genetics study systematic biology and conservation, is a big interest in the genetic diversity in natural populations. Reflecting on the evolutionary history of the species, genetic diversity in natural populations is very useful for those who study plant population genetics, systematic biology and conservation.

Plant species across the wider geographical region can be divided into different ecotypes; this division could be influenced by ecological factors, which are more important for the geographical variation of plants. Therefore, successful management, preservation and reestablishment of sustainable populations of rare, threatened, or endangered species depend on a complete understanding of the species, including levels and structure of genetic variation. In Lithuania, quite a lot various lily  species are introduced. However, not all species of our weather conditions are suitable. That’s why we have to do morphologic and genetic researches to learn out plants resources. It is also important to compare the results with the global genetic results and the plant of origin. In Lithuania there weren’t any lily genetic researches done. Molecular markers are recognized as a good method for the identification of plant species. Accordingly, these markers could be helpful in the breeding aimed at new cultivar development through early detection and screening of plants that have so far escaped cultivation. Also to improve plants taxonomy or in fine cultivars number in collections, genetic diversity of plants was detected using various methods. Such methods as restriction fragment length polymorphism , analysis of chloroplast DNA random amplified polymorphic DNA , simple sequence repeat  and intersimple sequence repeat  have enabled researchers to investigate genetic diversity among various plant species across natural populations. The efficiency of these methods has already been demonstrated in phylogenetic and population genetic studies. Local populations of traditional cultivars provide a valuable resource for plant breeding as well as for the preservation of genetic diversity. The exploration, evaluation, and conservation in situ and ex situ of genetic diversity in natural populations are imperative to guarantee sustainable development. Random amplified polymorphic DNA method has often been used for estimating genetic variation within and among plant populations, cultivars and species, and also was used for determining the hybridism of inter-specific hybrids in the genus Lilium. Recently, the usefulness of inter-simple sequence repeat  markers that amplify the genomic sequence between two simple sequence repeats  using anchored simple sequence repeat  primers has also been reported. To find out recourses of lily in Lithuanian, it is necessary to evaluate the variability using of genetic methods. It is also very important to evaluate and compare the genetic variation between species and wild populations of wild samples. There are some problems with naturally grown wild lily populations and introduced Lilium species, varieties and hybrids. There could be several origin possibilities; they could be sowed out from introduced lilies, hydroponic channel also there could be hybrids. After molecular DNA analysis to choose lily we can more efficiently and faster to make the biggest part of selection work processes. Also there would be a possibility during plant regeneration process to control proportions of variability and stability.This study offered the first detailed analysis of the genetic diversity and population structure for 3 different lily species 1 varieties and 1 hybrid grown in Lithuania based on ISSR molecular markers that have been proven to be valuable for the determination of genetic diversity.

The ISSR-PCR identified relatively high genetic diversity , considerable genetic differentiation among species  and the gene flow  at the species level. Compared with other Lilium species, polymorphism of analyzed groups is higher than that of 13 Lilium species and of 16 interspecific hybrids, and that of the Asiatic hybrid lily-Montreux and Connecticut King, and also that of the Lilium tsingtauence and higher than in the Lilium maculatum var. bukosanense. The effective gene flow per generation  of all analyzed groups is higher than one successful migrant per generation , possibly to overcome the diversifying effect of random drift. Lilium is a long-lived perennial grassy species, which should enable the species to maintain a high level of genetic diversity. Furthermore, its high genetic diversity could come from seedling establishment in the early period. Our observations suggest that events that potentially reduce genetic diversity and increase genetic differentiation among populations such as genetic drift or inbreeding might have not occurred yet with the restricted distribution. Based on Nei’s gene diversity and AMOVA analyses for 3 lily species, 1 varieties and 1 hybrid genetic differentiation among species  and fixation index  also signify a genetic structure. The non-random temporal or spatial distribution of genetic variations of alleles and genotypes is often referred to as the genetic structure of a population. The level and distribution of genetic variability among and within groups can be shaped with a great number of factors including pollen and seed dispersal, successional stages, geographic distribution range, adult density,mating system, colonization history, and natural selection. We hope that the genetic diversity and structure of analyzed five different lily groups reported here offer important information for this endangered species .The Cucurbita genus, of American origin, is one of the most variable genera within the Cucurbitaceae family. The main economic value of the species resides in the consumption of its immature fruits as vegetables, commonly known as summer squashes. Summer squashes of the Zucchini type rank among the highest-valued vegetables worldwide, whereas the “winter squash” types  of Cucurbita pepo and related Cucurbita spp. are food staples and rich sources of fat and vitamins in developing countries. It has various medicinal effects comprising antidiabetic, antihypertensive, antitumor, antimutagenic, immunomodulating, antibacterial, anti-hypercholesterolemic, intestinal antiparasitic, antalgic, and anti inflammation effects, and utilization possibilities of various Cucurbitaceae species have been reported. A wide range of pathogens hamper the cultivation of C. pepo, with more than eight different viruses infecting the crop. Among these viruses, Papaya rings pot virus  and Zucchini yellow mosaic virus  are the most important due to their prevalence and the degree of damage caused, which reduces crop and fruit quality. The control of these viruses is difficult and conventional breeding has not succeeded in producing new varieties with resistance to more than one virus species.